A new study published earlier this month found that taking a calcium supplement could increase your risk of developing polyps in your colon—especially if you have had polyps in the past. Calcium supplements are among the most commonly recommended—and taken—nutritional supplements.
Although adequate calcium intake throughout life (and especially during childhood and adolescence) can reduce the risk of osteoporosis later in life, the benefits of calcium supplementation in midlife and beyond appear to be modest, at best. And a growing body of evidence suggests that calcium supplements may increase the risk of other problems, such as kidney stones, heart disease, and now colon polyps.
In this latest study, researchers recruited 2,000 people who had previously been diagnosed with polyps and divided them into four groups. One group took a supplement providing 1,200 mg of calcium per day—a pretty standard dosage. A second group took 1,000 IU of vitamin D. A third group took both calcium and vitamin D. A fourth group took a placebo.
The researchers probably hoped that those taking the calcium would have a lower incidence of polyps. This would have been in line with the results of a meta-analysis published in 2016, which found that taking 1,200 to 2,000 mg of calcium per day led to a modest decrease in the incidence of colon polyps. However, this was not what they saw. Wait for it...
The Link Between Calcium and Colon Polyps
Five years into the study, no significant difference was seen between the groups. But fortunately, the study did not end there. Ten years into the study, the groups taking calcium were three times more likely to develop additional colon polyps than the group taking the placebo. There was no link between calcium intake from foods and an increased risk of colon polyps.
It’s important to point out that polyps are not cancerous—but they can eventually turn into cancer if they are not removed. This is why those screening colonoscopies are so important. Catching and removing these relatively benign polyps before they can become malignant can save your life. And because the patients in this study were being closely followed, none of them developed colon cancer.
But even if it doesn’t lead to cancer, taking a supplement that increases the occurrence of colon polyps may lead to unnecessary medical costs and risks due to more frequent screening and removal of the polyps. I speak from personal experience here.
Here's Where It Gets Personal
When I went for my first screening colonoscopy a couple of years ago, the doctor found a large polyp which required two additional procedures to completely remove. Instead of returning after five or ten years for my next screening, I now have to have annual rechecks. Although my initial procedure was at an outpatient endoscopy center, I now have to do these in a hospital, which costs both me and my insurance company about five times as much as the endoscopy center. And, of course, every time they put me under, there’s a risk that something could go wrong. While the likelihood of injury or infection is pretty low, having to have this procedure every year instead of every decade obviously increases my risk substantially.
Of course, I’m super grateful that this was caught early and I take every opportunity to encourage people not to put off their screenings. I’ll take the inconvenience and expense of frequent colonoscopies over chemotherapy and surgery any day. But if taking calcium supplements increases the number of people who require this more intensive follow up, that’s a pretty big price to pay. Especially if it’s not actually doing that much to prevent fractures or osteoporosis.
Let's Get Our Calcium from Foods, Not Pills
None of the harmful effects observed with calcium supplements have been seen in people who get their calcium from foods. And even if your diet falls short of the recommended intake, you can probably fill the gap with a much smaller dose than people usually take.
Doubling up on your calcium will not make your bones twice as strong. But it may increase your risk of other health problems.
The total recommended intake for calcium is 1,000 to 1,300 mg, depending on your age. Most calcium supplements (and most of the research on calcium supplementation) are designed to provide 1,000 to 2,000 mg of supplemental calcium per day. But this is almost always overkill.
According to the National Health and Nutrition Examination Survey (NHANES), the average American takes in over 1,000 mg calcium per day from foods alone. Even those who are falling below the recommended intake could meet the recommended intake by taking just 250 mg supplemental calcium. So why are we all taking so much? Doubling up on your calcium will not make your bones twice as strong. But it may increase your risk of other health problems.
It Takes More Than Calcium
Finally, remember that calcium is only one of many nutrients needed for strong bones. Vitamin D helps your body absorb and use calcium but strong bones also require a host of other vitamins, minerals, essential fatty acids, and even protein. Leafy greens and other fruits and vegetables, legumes, nuts, seeds, whole grains, fish, and lean meats all contribute important bone-building nutrients. For more, see my previous episode on Diet for Healthy Bones.
And don’t forget about “vitamin X,” or Exercise, which not only increases the health of your bones but helps improve muscle strength and balance and preserves your overall vitality as you age. For more tips on how to get fit and strong at any age, be sure to check out the Get Fit Guy Podcast.
Veggie burgers have been around for decades. And as the popularity of plant-based and flexitarian diets has grown, there are more and better options in this category than ever. You probably wouldn’t ever have mistaken one of these for actual beef. But if you’re looking for something meatless to put on a hamburger bun, there are plenty of choices.
There’s a new meatless burger on the market that claims to look, cook, taste, and chew so much like actual ground beef that you might not be able to tell the difference. Having sampled it this week, I have to say that this claim is actually not far off the mark.
The Impossible Burger is made from wheat, soy, and potato protein, and coconut oil. The makers have done an admirable job configuring those ingredients into something that looks and acts remarkably like raw ground beef. You can even choose whether you want to cook it well done or still pink in the center.
But the magic ingredient that is responsible for its beefy taste and appearance is heme, an iron-containing molecule that is abundant in animal tissue. While all animal foods contain heme iron, red meat is much higher in heme iron than chicken or fish, and that’s what provides much of the color and flavor that we associate with red meat. Because it’s so well absorbed, heme iron is terrific at treating and preventing iron deficiency and anemia.
Plants tend to contain the much-less-absorbable nonheme form of iron. But the clever folks at Impossible Foods have figured out how to get yeast to produce a plant-based source of heme iron that’s identical to the heme in red meat.
Heme iron may be a double-edged sword, however. Athough it’s very bioavailable, it’s also a highly reactive molecule which, in excessive amounts, could lead to cell damage. Studies have found that those who eat the most red meat have higher risks of colon cancer and other diseases compared to people who eat other types of meat or no meat at all. One of the working theories points to high intakes of heme iron as the culprit.
So, ironically, if you’re avoiding red meat because of its association with increased cancer risk, it’s possible that this meatless burger may present similar concerns. Keep in mind, however, that these worrisome associations between red meat and cancer are seen in those who eat red meat once or twice a day. Those who eat red meat just once a week have approximately the same risk as those who never eat meat.
Nutritionally speaking, the Impossible Burger has been formulated to approximate the nutritional profile of 80% lean ground beef—for better or worse. It contains a similar amount of protein and calories. It’s a bit lower in total fat but actually significantly higher in saturated fat. That's because unlike beef, which contains a mixture of saturated and unsaturated fats, coconut oil is virtually all saturated. So, if you avoid beef burgers in an effort to moderate your saturated fat intake, you might be better off with a turkey or bison burger.
Compared with cattle farming, the Impossible Burger uses far less land, water, and produces less greenhouse gas emissions.
If your main motivation in avoiding beef is out of concern for the welfare of the cows or perhaps the impact of cattle farming on the environment or climate—but you love the taste of red meat—then this might be a great solution for you. Compared with cattle farming, the Impossible Burger uses far less land, water, and produces less greenhouse gas emissions.
As you can see, there are a lot of different reasons that people choose to avoid meat or red meat. I don’t think this will be the ideal alternative for everyone. If you’re sensitive to soy or wheat, for example, this is not for you. And if you find the taste, texture, and appearance of meat disgusting, this is definitely not for you. But it is a pretty impressive feat of culinary engineering. We seem to be getting closer to being able to produce meat without any animals. Whether this ends up being an upgrade for us nutritionally we’ll have to evaluate on a case-by-case basis.
Curious? Right now, the Impossible Burger is only available in restaurants, not in retail or direct to consumers. You can check the company’s website to see if there’s a restaurant in your area. If you try it, I’d love to hear what you thought! And if you’re not interested in trying it, for whatever reason, I’d like to hear from you, too!
Share your thoughts below or on the Nutrition Diva Facebook page.
Hai-Ting asks: “What exactly is water weight? It’s a phrase that gets thrown around a lot. I would love to know what we are talking about. How and why do we gain and lose so much water?”
If you are in the habit of getting on the scale every morning (a practice which is linked with healthier body weights over the long-term) you’ve probably noticed that your weight can vary wildly from day to day—in ways that sometimes seem unfair. “How could I have gained two pounds overnight? I had a salad for lunch and skipped dessert at dinner. I should weigh two pounds less!”
It’s tempting to think whatever we did or didn’t eat yesterday should show up the next day on the scale. But it doesn’t work that way. As Dan Ariely pointed out in our recent interview, it takes a lot longer for dietary changes to result in fat loss (or gain). If you gain or lose three or four pounds overnight, most of that is probably due to water weight.
Where is Water Weight Stored
Our bodies contain a lot of water, but we’re not just giant water balloons. Water is held in a variety of places in the body. Some of these don’t change very much from day to day. Our bones, for example, are about 30% water but that stays relatively constant.
Other compartments, such as our stomachs and bladders, can hold relatively large amounts of water, but only on a very temporary basis. And here’s the thing: Water is heavy. A pint of water (or, for that matter, beer) weighs about one pound.
The amount of fluid in your stomach and bladder have a profound effect on your body weight at any given moment.
If you were to weigh yourself, drink 16 ounces of fluids and immediately weigh yourself again, you’d have “gained” one pound in about 15 seconds. A couple of hours later, a lot of that water will be collected in your bladder. Weigh yourself before and after visiting the bathroom and you can enjoy the thrill of “losing” up to a pound in 15 seconds.
Obviously, the amount of fluid in your stomach and bladder have a fairly profound (yet meaningless) effect on your body weight at any given moment. But that’s not the only thing we’re talking about when we mention water weight.
In between the stomach and the bladder, things get a bit more complex. As it passes through the small intestines, the water we consume is absorbed into the bloodstream and distributed throughout the body’s organs and tissues, where it is used for all kinds of things, everything from lubricating our membranes to metabolizing nutrients to maintaining electrolyte balance. All of these activities affect the amount of water retained in our bodies.
Water is a major component of perspiration, for example. Heavy sweating can cause us to lose a lot of water weight in a relatively short period of time. Run a few miles on a hot day and jump on the scale before rehydrating and you’ll see how much water you’ve lost. (You probably won’t, however, see how much fat you burned.)
Water is also involved in lots of different chemical reactions. Some reactions—such as converting carbohydrates into glycogen—require water. Others—such as breaking down proteins—release water.
Sudden changes in the protein or carbohydrate content of your diet can either lock up or mobilize relatively large amounts of water.
How Diet Affects Water Weight
If you dramatically reduce the amount of carbohydrates you are eating, your body will be forced to dip into the glycogen stored in your muscles and liver for energy. As the glycogen is used for energy, a lot of water is released into the bloodstream and routed to the kidneys for elimination. Obviously, this has nothing to do with fat loss but it does give low-carb dieters a big sense of accomplishment during the first few days of their diet.
Even if you don’t go low carb, suddenly reducing your calorie intake will also force the body to use its glycogen stores and result in some water loss. The effect is just not quite as dramatic as it is with a low carb diet.
This effect is also completely reversible. As soon as you start eating more calories or carbohydrates, your body will use some of those carbs plus some water to restock its depleted glycogen energy stores, leading to an increase in water weight.
But these sorts of changes in water weight don’t represent changes in your fat stores. That’s going to have more to do with how many calories you take in and burn over the long term, not how many of them are from carbohydrates.
Although it takes a lot longer to lose fat than it does to lose water, there is a pretty big consolation prize: The resulting changes in your body size (and how your jeans fit) are much more durable. Having a piece of bread with dinner won't undo them by morning.
How Kidneys Regulate Water Retention
Eventually, all the water in your body passes through the kidneys, which regulate how much water is either retained or eliminated in order to maintain the right amount of fluids and concentration of electrolytes. This process is directed by hormones released by the pituitary and adrenal glands.
Reducing your sodium intake (or, paradoxically, increasing water intake) can help reduce water retention.
Any health condition that affects the kidneys or the glands that secrete these hormones can cause this delicate balancing system to go awry—causing excess water retention. Less alarming but still frustrating is the temporary water retention that many women experience before their period, due to fluctuations in hormone levels.
What Foods and Nutrients Reduce Water Retention
There's not too much we can do about our hormones. But there are a few dietary factors that we can control. Eating a lot of salt, for example, can cause the kidneys to keep more water in circulation in order to dilute the extra sodium. Reducing your sodium intake (or, paradoxically, increasing water intake) can help reduce water retention.
It may also be useful to increase your intake of green vegetables. In addition to being high in water, they are also good sources of magnesium and potassium, which may help relieve water retention. In particular, dandelion greens and asparagus are known to have diuretic properties.
As tempting as it might be, I don’t recommend using diuretic supplements or teas to get rid of water weight, except as directed by a health practitioner. Overdoing it with diuretics can lead to dehydration and electrolyte imbalances, which can be potentially serious.
The Quick and Dirty on Water Weight
Water weight can come and go for a variety of reasons, but most are temporary and not related to long-term changes in body fat. Don’t get too freaked out (or impressed) by big swings on the scale. A moving average calculator can help smooth out those meaningless ups and downs and reveal what’s really going on with your weight.
Amanda recently asked me to comment on a study showing that eating five or more eggs a week could triple your risk of developing Type 2 diabetes. This study was highlighted in an online video posted by an MD who is also a well-known proponent of a vegan diet.
Although this particular commentator always cites published research to support his points, he can be very selective about the studies that he highlights. He tends to cherry pick those that support his point of view and ignore those that don’t. To be fair, this is something we are all somewhat liable to do.
Upon closer inspection, this study did not actually find that people who ate a lot of eggs were more likely to develop diabetes. Rather, it showed that people who had been diagnosed with diabetes reported eating more eggs than those who hadn’t. It’s a subtle difference, but an important one.
Interestingly, this study didn’t collect information about other aspects of their diet, just eggs. They didn’t ask, for example, how much bread, pasta, potatoes, soda, meat, fried foods, sweets, or vegetables they consumed. You have to wonder whether there might have been some other aspect of their diets that might have played a role.
But this is not the only study to look at the link between egg consumption and diabetes risk. So, what do the others say?
Is There a Link Between Eggs and Diabetes?
Other studies have also found a positive correlation between egg consumption and diabetes risk. But in every other study I found, those who ate the most eggs had a 20%-50% increase in relative risk. The 300% increase highlighted in the doctor’s video appears to be an outlier, to say the least. But that’s not the end of the story.
If you already know that you either do or don’t want to eat eggs and you’re simply looking for a research study to support your point of view, you can choose the study that confirms your conclusion. But, if you’re trying to decide whether or not eggs are a good choice based on the research, you’re likely to feel a little frustrated.
With so much conflicting data, what are we supposed to conclude? That’s where meta-analyses come in particularly handy. By pooling the results of lots of different studies on the same question, we can improve the statistical power of smaller studies, compensate for design flaws, and clarify inconsistent results.
In 2016, pooled data from 12 studies involving almost a quarter of a million subjects found virtually no relationship between egg consumption and diabetes risk. A second meta-analysis published just last year involving half a million subjects also found no relationship.
Should You Stop Eating Eggs?
There are lots of reasons that you might not want to consume eggs or animal products—and I’m not here to talk you out of them. But let’s say you do enjoy eggs, yet you’re also worried about developing Type 2 diabetes. The real question for you is whether avoiding eggs now will lower your risk in the future.
There are 3 other steps you can take that, in my opinion, will make a much bigger difference.
Unfortunately, that’s a question that hasn’t been researched. However, if reducing the risk of Type 2 diabetes is your primary goal, here are three other steps you can take that, in my opinion, will make a much bigger difference.
If you’re overweight, lose weight. Reducing your body weight by as little as 5% can significantly reduce your risk of diabetes, even if you are still overweight. (See: How to Lose Weight Without Dieting)
If you’re sedentary, get moving. Exercise can help improve your blood sugar metabolism and can also help you lose weight.
Reduce your consumption of added sugars and other refined carbohydrates, as these foods can contribute to high blood sugar and insulin resistance. See also: What is High Glucose?
This has been one of the worst flu seasons in a decade—and there are plenty of nasty coughs and colds going around as well. Is there anything you can do—nutrition wise—to bolster your defenses?
Does Red Wine Protect Against the Flu?
For example, you may have seen the story that went viral last week claiming that drinking wine can keep you from getting the flu. Alas, this was another example of headline writers run amok. In fact, after I posted their original headline (“Drinking wine will stop you from getting flu”) as a particularly egregious example, the UK’s Independent updated their headline to one that’s slightly less untrue. (“Drinking tea and wine could keep flu at bay”). But only slightly.
Guess what the study in question did not involve? Wine. That’s right. No wine was harmed (or even consumed) in the course of this particular study. No tea, either, for that matter. The researchers were testing the effects of resveratrol, a compound found in wine but also in tea, grape juice, and peanuts. The experiments were being done on mice. And the resveratrol did not keep the mice from getting the flu, because all of the unfortunate mice in this study already had the flu. But the resveratrol did seem to help the mice fight off the infection.
But should you come down with the flu, drinking wine is not recommended. For one thing, you’d probably die of alcohol poisoning long before you got to the amount of resveratrol tested in these studies. Meanwhile, drinking alcoholic beverages will dehydrate you, which is going to make you feel worse, not better. If you want to increase your resveratrol, drink tea or grape juice or eat peanuts. It may not help, but it probably won’t hurt.
Can Vitamin D Protect Against the Flu?
Taking a vitamin D supplement could offer modest protection against the flu. Examining studies involving more than 10,000 people, researchers found that taking a vitamin D supplement reduced cold and flu infections by about ten percent. Among those who were low in vitamin D, however, taking a supplement reduced infection by a much more encouraging 50%.
Vitamin D is inexpensive, exceedingly safe, and has other benefits such as helping build strong bones. And low vitamin D levels are extremely common, especially during winter—otherwise known as flu season. Although it’s not a magic bullet, I’d say a vitamin D supplement is a no-brainer.
Can Probiotics Protect Against the Flu?
Probiotic foods and supplements might also offer a bit of extra protection. A review of about a dozen studies found that probiotic supplements could cut your risk of cold and flu almost in half and trim a few days off your recovery to boot. The caveat here is that the available studies aren’t of the best quality. Also, they weren’t all testing the same probiotic. There are thousands of strains of friendly bacteria out there, and they don’t all have the same benefits. Some might be better at protecting against infection than others.
This is why my strategy is to eat a variety of probiotic foods, including yogurt, kefir, miso, and fermented vegetables. The more different probiotic foods you consume, the wider the variety of microbes and the better your chances of getting the right ones. In fact, some studies suggest that the diversity of your gut population may be more important than which specific bug you have on board.
But once you’ve stocked the pond, you need to be sure to feed the fish (as it were). And that’s why it’s important to eat plenty of prebiotic foods as well. Those include legumes, nuts, whole grains, and other sources of fiber that provide sustenance for those friendly bacteria.
The Most Important Way to Protect Yourself
Whenever flu season comes around, I get lots of questions about which foods and nutrients will help build up our immune response. But I think we often focus too much on bolstering our immune system and not enough on reducing the number of bugs our immune systems will need to protect us from.
By far, the most effective strategy for reducing your risk of getting sick is to limit contact with sick people. This is easier said than done. Unfortunately, a lot of people continue to go to work and school, attend social events, concerts, and movies, and board planes, even when they aren't feeling well. If you are getting sick, you can do your boss, clients, customers, students, teachers, friends, and neighbors a huge favor by staying out of public—especially during the first three or four days of your illness, when you are likely to be most contagious.
My strategy is to eat a variety of probiotic foods, including yogurt, kefir, miso, and fermented vegetables.
If someone in your household gets sick, there’s only so much you can do to keep your distance. But at least you have the advantage of knowing that they are sick. Try to avoid sharing cups, glasses, and even hand towels and dish towels. Keep a canister of disinfecting wipes on the counter in the kitchen and bathroom and wipe down surfaces regularly until everyone is feeling better.
How Employers Could Help Reduce Flu
Employers, teachers, and pastors could help reduce the rate of flu infection by actively encouraging people not to drag themselves to work, school, or church when they are sick. You are not a hero for showing up to the meeting and infecting everyone there. I also wish businesses with strict cancellation policies would consider a more lenient policy during active flu season, so that people aren’t showing up sick for their appointments in order to avoid forfeiting their fees. I realize that this clemency could be abused. But I think having employees and customers show up sick ultimately costs businesses way more than having a couple of healthy people calling in sick.
Unfortunately, not everyone sees it this way. And a good percentage of the people you will come into contact with this week are going to be sick. Flu and cold viruses travel through the air, so if you notice someone coughing or sneezing, try to keep your distance. If they are not polite (or aware) enough to cover their coughs and sneezes properly (that is, NOT with their hands), then try to cover your nose and mouth with a scarf or tissue.
Germs can also be transferred from contaminated surfaces to your nose, mouth, and eyes via your hands. Hand sanitizing gels are better than nothing but, believe it or not, careful hand-washing is the best way to decontaminate your hands—so take advantage of every opportunity. And take heart. The flu season usually begins to abate in early spring, which is just a few weeks away.
When we think about taking nutrients into our bodies, we usually think about swallowing them, in the form of pills, powders, or that radical format known as food. For that matter, when we talk about nutrient absorption, we’re usually talking about the absorption of nutrients from the digestive system into the bloodstream.
But a handful of companies are trying to change the way we think about nutritional supplementation. Instead of swallowing a handful of pills and worrying about whether or not they are being absorbed, why not bypass the digestive tract altogether and apply them directly to your skin?
Nicotine, estrogen, testosterone, and certain pain medications can all be delivered through the skin through medicinal patches, gels, or creams. Why not vitamins and minerals?
Are Nutrient Patches the Future?
The US military, for example, is working on a skin patch that could deliver nutrients and other compounds to soldiers “during periods of high-intensity conflict,” when getting adequate nutrition from food might be challenging. Scientists working on the project don’t expect to have anything ready for field testing for another ten years or so.
But you don’t have to wait for those fusty old scientists to dot every i and cross every t. There are companies who will take your money RIGHT NOW for patches, gels, and bath salts containing magnesium, vitamin D, CoQ10, and various other herbs and nutrients that claim to alleviate nutrient deficiencies, boost your energy, and (of course) help you lose weight.
However, I’m skeptical that any of these substances will actually end up in your bloodstream. And you should be too.
Your Skin is Tougher Than You Think
The skin is actually designed to be a fairly impenetrable barrier. And good thing, too. Imagine for just a moment if everything that touched your skin ended up in your bloodstream!
Lotions and cosmetic potions often tout their vitamin-drenched formulas. And while these nutrients may (or, then again, may not) have cosmetic effects on the surface of the skin, very little if any of those nutrients are penetrating beyond the skin’s surprisingly tough outer layers.
That’s why we can slather our skin with mineral-based sunscreens all summer long without developing a zinc overload! Studies have shown that the topical application of zinc-containing sunscreens has minimal if any impact on the amount of zinc in your blood.
For that matter, studies have found that magnesium is not very effectively absorbed through the skin, either. That doesn’t seem to hurt the sales of topical magnesium products claiming to be a more effective way to absorb magnesium. Buyer beware.
In order to be absorbed through your skin and into your bloodstream, a compound needs to have at least two things going for it. It needs to be lipophilic, or fat-soluble. And it needs to be very, very small. A lot of the compounds found in commercially-marketed transdermal patches are neither.
Of course, there are ways to get around these limitations. You can break a large molecule down into nanoparticles, or encase it in a substance that diffuses more easily into the lipid layer of the skin. You can use tiny little needles to poke tiny little holes in the skin, which allows the substance to penetrate into the deeper tissues. You can use chemicals to alter the surface of the skin and make it more porous. You can even use electrical stimulation to open the pores, or a technique known as microdialysis.
Some vitamin patch productes include disclaimers like: “This product has not been tested for safety or efficacy.”
All of these are strategies that are currently in use or being developed by pharmaceutical companies and the military. However, you can be pretty sure that $2 vitamin D patch doesn’t include any of those features. Perhaps that’s why the product website includes the disclaimer, “This product has not been tested for safety or efficacy.”
No, seriously. It actually says that.
Similarly, I very highly doubt that much if any of the green tea extract or garcinia cambogia embedded in their weight loss patch is actually going to end up in your bloodstream. Then again, even if it did, it probably wouldn’t result in noticeable weight loss.
On the plus side, sellers of trasndermal patches point out that they completely avoid the problem of nausea or stomach upset that pills can sometimes cause. They sure do! You could also avoid stomach upset by dissolving your supplements in water and using it to water your plants—a nutrition strategy which would be about as effective as an over the counter vitamin patch.
Transdermal nutrition may indeed be the wave of the future! But I'm afraid the future is not yet here.
A lot of people believe that eating more frequently boosts your metabolism. I debunked this in the first year of the Nutrition Diva podcast, which was (can you believe it?) ten years ago. The research that I reviewed back in 2008 for my episode on Metabolism Myths simply didn’t support the notion that you could burn more calories simply by dividing your daily intake into smaller, more frequent meals.
But our understanding of human nutrition is constantly evolving and it’s always worth revisiting those stances in light of newer evidence. In The Abs Diet, author David Zinczenko claims that eating six meals a day will help you reveal that six-pack you’d like to flaunt. (Due to inflation, we now strive for an eight pack, but back then, an abdominal six-pack was considered sufficient.)
“You have to eat more if you want to lose more,” he writes, “[And] there’s science to support the fact that more meals work.” He then describes two specific studies to prove that eating more frequently will help you burn more fat.
What's the Proof for Six Meals a Day?
One of these studies, dating from 2000, involved nationally-ranked, 15-year-old gymnasts and 26-year-old runners, all of whom were female. The study didn’t look at how often the women ate. Instead, it was looking at the difference between calories consumed and calories burned on an hourly basis. And they found that the athletes who replaced the calories they burned more quickly had less body fat than those who waited longer.
Remember: these are world class athletes. Their body fat percentages were all very low to be begin with. So the change in body fat was the difference between “very low” and “very very low.”
What this study really shows is that when you are training at the level of a world class athlete, you don’t want to delay your post-workout recovery meals. I’m really not sure, though, how relevant this is to Zinczenko’s audience.
The other study he cites, from 1996, involved 12 boxers who were put on extremely low calorie diets (just 1200 calories a day) for two weeks. Boxers will often crash diet before events in order to qualify for certain weight classes. In this study, six of the boxers divided their 1200 calories into two meals and the other six ate the same number of calories divided into six meals. Both groups lost a bunch of weight and, not surprisingly, a significant amount of lean muscle. That’s what happens when you lose weight too quickly. But the loss of muscle was a bit less in the group who ate more frequently.
What this study really shows is that when you are crash dieting, you’ll lose less muscle if you eat more frequently. But if your goal is a six pack (or any multiple thereof), you don’t want to be losing muscle. You want to be losing fat. Crash dieting is not recommended. So, again, I’m not sure this study is all that relevant to the claim or the audience.
How Does It Work for Real People?
But these are not the only studies out there to look at the relationship between meal frequency and weight loss or body composition. And some of the other studies I found might be a bit more applicable to you and me, and to most of those who are reading The Abs Diet.
In 2017, researchers analyzed data on more than 50,000 adults. This was data from the Adventist Health Study and involves a population that tends to be healthier than average. But they are not elite athletes. These subjects are also what we call “free living.” That means their meals were not being provided by researchers and they were not living in a research lab. They were living in their homes, working at their jobs, cooking their own food, and so on. Kind of like you and me. The researchers found that the people who ate more than three times a day weighed more than those who ate less frequently.
This isn’t that surprising. Other research has shown that those who eat the most frequently tend to consume the most calories. (Unfortunately, when people embrace this idea of eating six small meals a day, they often overlook the “small” part of the equation.)
We can also find some studies which seem to support the idea that eating more frequently might help with weight loss. For example, eating more frequently has been shown to improve appetite control and this may help people avoid overeating. But this is not the same thing as revving up your fat-burning metabolism. It’s just a way of managing your behavior.
There's a Study to Support Every Conclusion
Here's the thing about nutrition research—especially the kind that involves humans. No matter what question you are asking, there are usually multiple studies with conflicting results. That means that if you start with a certain conviction or point of view, you can almost always find at least one study to back you up. You can stop as soon as you find a study that says what you want it to. Or, you can look at all the studies and see where the consensus lies.
People who ate more than 3 times a day weighed more than those who ate less frequently.
In 2011, the International Society of Sports Nutrition published a position paper in which they reviewed all the relevant research on this question. They agreed that for elite athletes who are on restricted calorie diets, eating more frequently can help preserve muscle mass. However, they also concluded that more frequent meals will not affect body composition in more sedentary populations, and that increasing meal frequency will not help anyone burn more calories.
A few years later, in 2014, Professor Ashima Kant looked at 16 different studies on meal frequency and published her analysis in the journal Advances in Nutrition.
“Frequent eating is associated with higher energy intake, yet beliefs about the possible beneficial effect of higher eating frequency for managing body weight persist,” she writes. “Overall, the [...] findings [...] suggest that beliefs about the role of higher eating frequency in adult weight management are not supported by evidence.”
Will Eating More Frequently Help You Lose Weight?
Over the last ten years (and more), I’ve taken a lot of stances on various aspects of nutrition, informed by the available research. Sometimes, newer research prompts me to change my position. But in this case, I’m sticking with what I said ten years ago.
If eating smaller more frequent meals helps you manage your appetite better and allows you to make better choices, go for it. But eating more frequently—in and of itself—is unlikely to have a measurable effect on your metabolism or abdominal fat. And if you do favor more frequent meals, be careful that eating more frequently doesn’t lead you to eat more than you need.
Questions? Comments? Post them below or on the Nutrition Diva Facebook page.
Some popular diet trends recommend eliminating all forms of oil from your diet—including oils that are often promoted as healthful, such as olive oil. Is an oil-free diet healthier?
Nutrition Diva listener Joy recently asked about this in a Facebook discussion. “What do you think about the idea that oil is unhealthy and should be avoided?,” she wrote. “I've noticed that some plant-based recipe blogs I like highlight their oil-free recipes. And a doctor told me I should work on eliminating ALL oil (not fats, just oil) from my diet. If you haven't done a podcast on this topic, please think about covering it!”
Your wish is my command, Joy. Let’s take a closer look at some of the arguments against oil.
Is Oil Unhealthy Because it is Processed?
Oils are generally extracted from whole foods. Olive oil is pressed from whole olives, corn oil is pressed from corn, and so on. In the process of extracting the fat, valuable nutrients (such as fiber) are left behind. Oil is also much more calorie dense than the whole foods it is pressed from.
This is similar to arguments I’ve made against fruit juice. When we squeeze an orange, we remove the fiber and end up with a more concentrated source of sugar and calories. We can also drink a glass of juice much more quickly than we can eat an orange, and this can lead to overconsumption.
Olive oil is most commonly used to dress a salad or roast vegetables. Does adding oil to your salad add calories? You bet. Does it make those vegetables less nutritious? Not at all. In fact, adding oil to your salad helps you absorb more of the nutrients in those vegetables. And if it makes those vegetables more appealing and palatable, so that you eat more of them (and less of other things), it’s a win all the way around.
This seems to be the case for Cheryl, who posted, “Since I stopped limiting my olive oil years ago, I've eaten way more vegetables—because they taste great with oil and not as great without it.”
As for valuable nutrients being left behind, many of the most beneficial nutrients in olives, nuts, seeds, and avocados—such as omega-3 fatty acids, phytosterols, vitamin E, and polyphenols—are fat soluble. These nutrients are not only present in the oil, but they are often in more concentrated amounts than you’d get from eating the whole foods.
Can Consuming Oil Lead to Weight Gain?
One website promoting oil-free diets claims that “Oil...has more calories per gram than any other food...and without any fiber or water in it, oil lacks the bulk to convey to your senses how many calories you have eaten; this virtually guarantees you will consume more calories at the meal than you need.”
It’s absolutely true that oil is a concentrated source of calories but I don’t buy the argument that including oil in your diet will inevitably lead you to consume too many calories and gain weight.
The Mediterranean diet provides another counterargument to the claim that including oil in your diet will lead you to gain weight. This dietary pattern gets a large portion of its calories from fat, in general, and olive oil, in particular. And yet those who follow a Mediterranean diet pattern are less likely to be overweight than those who follow a standard American diet, which is somewhat lower in fat. (It’s also lower in vegetables.)
Whether or not oil is healthful or unhealthful depends a lot on the company it keeps. Eating a lot of potato chips, french fries, cakes, cookies, and other pastries could definitely lead to excessive calorie consumption. But the oil is not what makes these foods problematic. They also contain high amounts of salt, sugar, and/or refined white flour.
Olive and avocado oil are both high in heart healthy monounsaturated fats and polyphenols.
If you are minimizing your intake of fried foods, refined grains and added sugars, I’m not that worried about how much olive oil you’re consuming.
Some Oils are Healthier Than Others
Although I don't think there's a good argument for eliminating all oil from your diet, some oils are definitely healthier than others.
Olive and avocado oil are both high in heart healthy monounsaturated fats and polyphenols.
Coconut oil is very stable at high temperatures, so it’s a good choice for high heat cooking.
Canola and walnut oil are both good sources of omega-3 fats.
One of the sillier arguments I saw against oils is that "they may also lead to increased bleeding through thinning of the blood;" This blood-thinning action, which helps to lower the risk of blood clots and stroke, is one of the reasons that omega-3 fats lower the risk of heart disease.
Vegetable oils pressed from corn, soy, and sunflower seeds are perhaps the least healthful choices. These oils are very high in polyunsaturated fats, which can create harmful compounds when heated. They are also quite high in omega-6 fats, which can prevent those healthy omega-3s from doing their job.
Which Oils Should You Use or Avoid?
Because different oils offer different advantages, I use a variety of different oils. Olive oil is my primary cooking oil. I use coconut oil if I’m stir-frying at high temperatures. I might also choose coconut, walnut, toasted sesame, or another specialty oil for the specific flavor it contributes. On the other end of the spectrum, I keep a bottle of canola oil around for those times when I need a very neutral flavor. I generally do not use corn, soy, or other vegetable oils.
Joe writes: “I just came across some steaks in the freezer and parts of them look as if they’ve already been cooked. They were definitely raw when I put them in there! Is that what they call “freezer burn”? Are these steaks still safe to eat?”
Yup, it sounds like you’ve got some freezer-burned steaks on your hands, Joe. And yes, they’re still perfectly safe to eat—assuming, of course, that they were safe when you put them in the freezer and that you haven’t had any power outages that caused things to thaw.
But the parts that look cooked probably won’t taste very good once those steaks have been thawed and then cooked for real. I’d suggest thawing the steaks and cutting the burned parts away before cooking them.
But steaks don’t grow on trees. So, let’s be sure this doesn’t happen again.
What is Freezer Burn?
On the face of it, freezer burn seems sort of mysterious. How can raw food get cooked by sitting in the freezer? Despite appearances, however, Joe’s steaks have not been partially cooked. To explain what’s going on here, I turned to Sabrina Stierwalt, host of the Everyday Einstein podcast. Can you explain the science behind freezer burn?
Everyday Einstein: Freezer burn is the dehydration or removal of water from our frozen foods. When the water molecules in food are frozen into ice crystals, those ice crystals will leave the food’s surface in favor of the dry freezer air if the food is exposed to air. The ice leaves via a process called sublimation—the molecules go directly from a solid (the ice) to a gas (water vapor). So if you missed a spot in your saran wrap coverage or you didn’t get that lid on the ice cream all the way, those foods will be more vulnerable to freezer burn.
Fluctuating temperatures in your freezer can also lead to freezer burn in even the best wrapped foods. Warmer temperatures will cause the ice crystals to melt, and if that water drips off the surface of the food, dehydration takes place.
Nutrition Diva: So, obviously, having a package with a lot of air in it (or packaging that doesn’t keep the air OUT) might increase the risk of freezer burn. But does the water content of foods come into play? Vegetables are very high in water, for example, but meat is relatively low in water. Are foods that are high in water more or less susceptible?
Everyday Einstein: If a food has a higher water content, it has more water to lose before freezer burn makes it inedible. So, a frozen lasagna is going to be more vulnerable than frozen soup—especially if it’s not well wrapped. Similarly, because meat has a lower water content than vegetables, it’s more likely to get freezer burned. Given enough time, the ice crystals will eventually find their way out. So, different foods will have different freezer shelf lives.
By minimizing contact with air, we can minimize freezer burn.
How to Prevent Freezer Burn
Now that we understand what causes freezer burn, we can take steps to prevent it.
Wrap foods tightly. By minimizing contact with air, we can minimize the dehydration and oxidation that leads to freezer burn. If you’re storing foods in containers (as opposed to wrapping them in something), match the size of the container to the contents so that you don’t have a lot of air in the container. Remember to leave a little extra room for the contents to expand slightly when they freeze.
Freezing is not forever. The longer foods are in the freezer, the greater the risk of freezer burn, so don’t leave foods in the freezer for too long. Write the date on the package when you put it in the freezer and keep track of your inventory. Try to eat foods within three or four months of freezing them.
Make sure the freezer stays cold. If temperatures are fluctuating above 0 degrees F (-18 degress C) it can speed the movement of water out of the food and into the air in the freezer. Keep a thermometer in the freezer so you can check the internal temperature of the freezer. If it’s too high, you can adjust the setting on your freezer or refrigerator. Try to open and shut the freezer as quickly as possible to minimize fluctuations.
My thanks again to Sabrina Stierwalt of the Everyday Einstein podcast for stopping by. If you have a question for Sabrina about science or a question for me about nutrition, post them below.
You can also reach me through the Nutrition Diva Facebook page but as you probably know, Facebook has recently made some big changes to what is showing up in your newsfeed. If you want to continue to see the nutrition tips, research, links, videos, recipes and Q&A that I post on Facebook, you can edit your Newsfeed Preferences to tell Facebook to include that in your feed. (Here's a quick video with details).
Our theme all this month is Healthy Habits and this week I spoke with behavioral economist and author Dan Ariely. He’s written several books including his 2008 bestseller Predictably Irrational: The Hidden Forces That Shape Our Decisions and his more recent title Dollars and Sense: How We Misthink Money and How to Spend Smarter. Dan Ariely teaches at Duke University and he’s the founder of the Center for Advanced Hindsight. (Get it?)
Dan has spent his career trying to understand (and explain to the rest of us) why we make choices that are clearly not in our best interest. Things like buying lottery tickets and selling stocks when they lose value and, of course, eating things that we know are going to keep us from looking and feeling the way we want to.
And, in fact, his latest project is one that focuses on helping people lose weight and get healthier. It's a bathroom scale called Shapa and the interesting thing about this scale is that it doesn’t tell you what you weigh. Instead, it simply tells you whether your weight is trending up, down, or staying the same. (This is very similar to the approach that we use in our sustainable weight loss program. In fact, the name of thatprogram is Weightless!)
When trying to develop healthy habits, we should focus on rewarding the behavior instead of the outcome.
In a pilot study, Dan's group recruited volunteers who either weighed themselves every morning on a conventional scale or on the Shapa scale. While the group who used the regular scale gained a bit of weight over the course of the study, the group that used the Shapa scale lost about 1% of their body weight each month.