My weekly health class assignment was to write a report on a controversial health topic. I chose meal frequency (is it necessary to eat every 3 hours for fat loss or not?) ….I referenced my resources and can provide a bibliography if you care to see 😉
Give it a read and tell me what you think! ❤ Cierra
By Cierra Vermeulen
Is it REALLY Necessary to Eat Every Couple Hours for Fat Loss and Muscle Retention?
If you have read any magazine or book on dieting to lose weight in the past several years, you probably have read statements like this: “You must eat often throughout the day to stoke your metabolic fire”, or “Eat smaller meals more often to control your appetite”, and “Fasting will make your body freak out and go into starvation mode!” ….Commonly the advice given will be to eat about 6 small meals a day ( none over 300 calories! ), and these meals should be evenly spread about 3 hours apart. Why?
The reasons given are usually that eating so often, in small amounts, will help keep your blood sugar stable, keep you mentally sharp, increase your metabolism, keep you from binging, prevent your body from consuming your muscles for fuel (catabolism), and of course, if you are a breakfast skipper you will without a doubt get fat. An article from Shape magazine about 10 Ways to Increase Your Metabolism urges readers never to skip meals, saying “Eat six small meals a day to avoid blood-sugar spikes and minimize urges to binge. Try to schedule meals at the same time each day. If you feed yourself well throughout the day, you’ll learn to understand when your body truly needs food. You can’t starve yourself and expect to make good choices at the next meal.” This all sounds perfectly reasonable. Let’s dig a little deeper!
So first, let’s address the idea that eating often lights up your metabolic fire. When you eat, your metabolic rate does increase for a couple hours. This is because your body actually uses energy, to break down the energy in food. This is the Thermic Effect of Food (TEF). The amount of energy expended is proportionate to the amount of calories and nutrients in a meal. This is important. If you are to take 3 meal plans, one eating 3 meals, one eating 6, and one eating 9, and each of these meal plans has the person eating the same total amount of calories and macronutrients, the bigger meals would have a big boost in metabolic rate that would slow down again closer to the next meal, and the small, 9 times per day meals would have a very weak, but steady boost in metabolic rate, and the 6 times per day plan would fall in the middle. But at the end of the day when all the nutrients have been absorbed by the body, there will be no difference in TEF. The energy expended would be identical for each meal plan. Here is a more mathematical breakdown of how this works from a research review done by Lyle McDonald of bodyrecomposition.com: “While TEF differs for the different nutrients, on average it constitutes about 10% of a typical mixed diet (this varies between nutrients and slight differences may be seen with extreme variations in macronutrient intake). So every time you eat, your metabolic rate goes up a little bit due to TEF. Aha! Eat more frequently and metabolic rate goes up more, right? Because you’re stimulating TEF more often. Well, no. Here’s why:
Say we have two people, both eating the same 3000 calories per day from identical macronutrients. One eats 6 meals of 500 calories/meal while the other eats 3 meals of 1000 calories/meal and we’ll assume a TEF of 10%. So the first will have a TEF of 50 calories (10% of 500) 6 times/day. The second will have a TEF of 100 calories (10% of 1000 calories) 3 times/day. Well, 6X50 = 300 calories/day and 3X100 = 300 calories/day. There’s no difference.”
Lyle’s comments were made from his readings of the study “Bellisle F et. al. Meal frequency and energy balance. Br J Nutr. (1997) 77 (Suppl 1):S57-70.” From the Abstract of this study comes this conclusion: “More importantly, studies using whole-body calorimetry and doubly-labelled water to assess total 24 h energy expenditure find no difference between nibbling and gorging. Finally, with the exception of a single study, there is no evidence that weight loss on hypoenergetic regimens is altered by meal frequency. We conclude that any effects of meal pattern on the regulation of body weight are likely to be mediated through effects on the food intake side of the energy balance equation.” In simpler terms, they concluded that it’s the number of calories consumed, not the frequency they are eaten in the day, that effects weight loss. How could this myth have become so widespread? Possibly many dieticians simply repeat what they have always heard, or perhaps misunderstand TEF, because though it does technically raise your metabolism, they may have missed the critical part that it raises proportionately to the amount of calories consumed.
Another possible reason the myth of “eating often raises metabolism” has lasted so long is that researchers have found, by observing the diet patterns of thousands of people, that those who eat more frequently tend to weigh less than those who eat less frequently. However, since these studies were not calorie-controlled and were done on normal people who aren’t paying a lot of attention to what/when/how much they eat, there is a big problem with these studies. Correlation does not equal causation, just because there is a correlation between low meal frequencies and high body weights, does not mean that the low meal frequency is responsible for the high body weights. Likely the people in these studies who eat less frequently are the types who have bad eating patterns, skipping breakfast but having a pastry at the office, skimping on food all day, and then gorging at dinner. This kind of person is unlikely to be very concerned with health and a good diet than people who eat more frequently (regular meal schedule). It also could be that these higher body weight people who eat less are actually eating less because they are skipping meals as a diet strategy. Those who are overweight are more likely to be on a diet. All in all, in the general population, the connection between low meal frequency and high body weight is based on patterns of behavior, not metabolic rate.
Ok, so now one part of the myth has been covered. Let’s move to the next….You need to eat small meals often to keep your blood sugar steady. That way you don’t get hunger pains, your energy will remain stable all day, and you will be mentally sharp and aware. However, our bodies are amazing and very good at keeping the important things in line. Think about our past, when the world was more primal. During long periods of fasting, our bodies had to be able to function when getting food was the most critical. Our bodies know that maintaining blood sugar is super important and have ways of keeping it in a healthy range even when in extreme conditions. Even after fasting for 23 hours, and then running for 90 minutes at 70% of maximum oxygen consumption, our blood glucose levels would remain at a normal concentration level. This is the results found in the study “Metabolic responses to exercise after fasting.” (Dohm GL, Beeker RT, Israel RG, Tapscott EB.)
It would take 3 days, or 84 hours of fasting to reach low enough blood sugar levels to affect your mental state, according to Martin Berkhan at Leangains.com, in his analysis of the study “Importance of blood glucose concentration in regulating lipolysis during fasting in humans.” (Klein S, Holland OB, Wolfe RR.)
As far as blood sugar and hunger goes, blood sugar is a short-term mechanism used to regulate hunger, because it is true that when your blood sugar is in a low (er) range, you feel hunger. This is mostly effected by your habitual meal patterns, regulated by the hormone ghrelin, along with other hormones. Your blood sugar follows the meal pattern that you are used to. This explains why people are able to adapt to regular periods of fasting without ill effect. In effect, there is no need to eat often to “maintain” blood sugar levels, since they maintain themselves without much help, and will adapt to whatever meal pattern you choose.
What about that often used argument for why you must eat often…that if you fast or skip a meal your body will panic and go into starvation mode? This one actually may surprise you! Starvation mode was necessary for survival in times of famine, and by no means does skipping a meal cause your body to think there is a famine. Starvation mode was used to allow us to live longer during tough times, so we could find something to eat! In fact, the earliest shown evidence for a lowered metabolic rate was after 60 hours of fasting, when one study showed a -8% reduction in resting metabolic rate. Other studies have not shown a reduction until after 72-96 hours have passed. (Berkhan M., Leangains.com) Even more surprising is this: in short term fasts of 36-48 hours, studies have shown an increase in metabolic rate of 3.6 to 10%. (Berkhan M, Leangains.com, citing studies by Mansell Pl, et al, and Zauner C, et al.) From a survival perspective, your body is releasing the hormones adrenaline and noradrenaline, both of which quicken our minds and make us more active. This would help people survive in their hunt for food so they could finally eat. But after the 60-96 hour window of time, the body would realize at
this point those hormones do more harm than good and would then switch over into starvation mode to conserve energy. ( Berkhan M., Leangains.com)
What should one take from all of this information? In my opinion, the point of knowing all this is to realize that “common knowledge” in the fitness and health industry is not always correct, and is often a lot of myths that come from vastly oversimplified scientific studies and concepts. For some people, eating 5 or 6 small meals a day works great for weight loss, and they are ok with all of the prep work and time that must be taken to eat every couple hours. For them, that is great, and they should do what works for them. My goal is to help those people who don’t like to pack coolers full of mini meals, people who don’t feel satisfied by itsy-bitsy servings, instead of feeling satisfied, they feel tantalized, which is not good on a weight loss program. Many people benefit from an “intermittent fasting” style of dieting, which is easy to implement and is often more convenient for those who actually go to work and don’t have time for 6 meals a day. Others may prefer a traditional 3 meal a day approach. There are many ways that can work, and people need to be aware of that and find the approach that works best for them.