Nutrition

May 20, 2011


How Many Meals a Day Should You Eat?

I recently wrote about the lack of scientific support for the theory that you should reduce carbs at night . In the same spirit (and by popular request), I thought I’d take the time to tackle another common nutritional theory. Namely, the claim that eating small, frequent meals stokes your metabolism.

I’m sure you’ve heard this one before. Bodybuilders and nutritionists have long preached that spacing out food consumption over five to six small meals a day is optimal for losing body fat. For years I too adhered to this belief. A wealth of emerging research, however, changed my viewpoint.


The strategy to eat small, frequent meals is based on the belief that when you go without eating for more than a few hours, your body senses deprivation and shifts into a “starvation mode.” Part of the starvation response is to decrease resting energy expenditure. In effect, the body slows down its metabolic rate to conserve energy. It’s a logical theory but alas it doesn’t seem to translate into practice, at least in the short-term (i.e. over about a 24 hour period or so). As such, the vast majority of studies examining metabolic rate have failed to show a clear advantage for increasing meal frequency.

On a similar note, the thought that frequent eating enhances the thermic effect of food (TEF)–a measure of the energy expended during digestion–is also flawed. A simple example should make this readily apparent. Let’s say you eat an 1800 calorie diet that averages a 10% TEF. If you space out meals equally so that you eat six times a day, the TEF would look like this:

Meal 1: 300 x .10 = 30
Meal 2: 300 x .10 = 30
Meal 3: 300 x .10 = 30
Meal 4: 300 x .10 = 30
Meal 5: 300 x .10 = 30
Meal 6: 300 x .10 = 30

Add up the numbers and total expenditure through the TEF will be 180 calories. Now let’s look at the same scenario except eating three times a day rather than six:

Meal 1: 600 x .10 = 60
Meal 2: 600 x .10 = 60
Meal 3: 600 x .10 = 60

Do the math and you’ll see it’s the same 180 calories expended through the TEF. This holds true regardless of how many times a day you eat.

Okay, so perhaps you want to focus on the benefits of more frequent meals on appetite. This is supposedly related to the effect of eating frequency on hormones. For one, it is claimed that large meals cause insulin spikes, which switch on various mechanisms that increase fat storage. The spikes then lead to a crash, where there is a tendency toward hypoglycemia (low blood sugar). Hunger pangs ensue and you invariably end up binging out. For another, an absence of frequent food is thought to increase the secretion of a gut hormone called ghrelin. Ghrelin is referred to as the “hunger hormone.” It exerts its effects by slowing down fat utilization and increasing appetite. Without consistent food consumption, ghrelin levels supposedly remain elevated for extended periods of time, increasing the urge to eat.

Frequent meals are purported to counteract these negative effects on hormones. Blood sugar is supposedly better regulated and, because there is an almost constant flow of food into the stomach, the hunger-inducing effects of ghrelin are suppressed, reducing the urge to binge out. Sounds logical, right? Sorry, another instance where logic and reality don’t mesh. Recent studies by Leidy et al. (1, 2) found no difference in appetite in those who consume six meals compared to three. Interesting, the researchers actually showed an increased satiety when the three-meal-a-day group followed a higher protein diet! On the other hand, consuming fewer than three meals a day does seem to have a negative effect on appetite (3), suggesting that this may be the minimum number of daily meals that need to be consumed from an appetite-control standpoint.

But what about body fat? Surely eating more frequently has to increase fat loss by some mechanism. Not! Provided calories are controlled, fat loss is similar between three-meals-a-day versus six-meals-a-day (4) A recent review paper (5) actually found that intermittent fasting–where people abstain from eating for upwards of 24 hours at a time–was equally as effective as caloric restriction in promoting weight loss. Read this again. The fasted subjects didn’t eat for an entire day at a time and still lost weight to a similar degree as those who ate daily meals. Apparently the starvation response is a lot more complex than some will have you believe.

A recent position statement by the International Society of Sports Nutrition covered the subject of meal frequency in detail. I’d highly recommend that you check out Alan Aragon’s critique of this paper for an in depth analysis.

In sum, current evidence doesn’t support the contention that eating more frequently enhances fat loss. Provided you eat a minimum of three meals a day, there does not seem to be any difference if frequency is increased beyond this number. Now this doesn’t mean that eating more frequent meals is a bad thing. I actually prefer a “grazing” schedule and have found it to be an effective eating strategy for my lifestyle. This is a personal choice that works for me. Others might find eating three times a day to be more appropriate.

The most important important factor here seems to be maintaining a regimented eating program–those who keep to a schedule see better results than those who don’t. It also should be pointed out that the majority of research studies have evaluated overweight subjects. Might more frequent meals help to strip away that last pound or two of body fat in otherwise lean individuals? As they say, further research is needed…

Stay Fit!

Brad

1) Leidy HJ, Tang M, Armstrong CL, Martin CB, Campbell WW. The effects of consuming frequent, higher protein meals on appetite and satiety during weight loss in overweight/obese men. Obesity (Silver Spring). 2011 Apr;19(4):818-24. PMID:

2) Leidy HJ, Armstrong CL, Tang M, Mattes RD, Campbell WW. The influence of higher protein intake and greater eating frequency on appetite control in overweight and obese men. Obesity (Silver Spring). 2010 Sep;18(9):1725-32.

3) Leidy HJ, Campbell WW. The effect of eating frequency on appetite control and food intake: brief synopsis of controlled feeding studies. J Nutr. 2011 Jan;141(1):154-7.

4) Cameron JD, Cyr MJ, Doucet E. Increased meal frequency does not promote greater weight loss in subjects who were prescribed an 8-week equi-energetic energy-restricted diet. Br J Nutr. 2010 Apr;103(8):1098-101.

5) Varady KA. Intermittent versus daily calorie restriction: which diet regimen is more effective for weight loss? Obes Rev. 2011 Mar 17.


11 Comments

  1. Thank you for clearing this up! I have been hearing conflicting stories for a long time now and finally decided on an eating schedule that simply worked best for me. Some days that is three meals a day and sometimes it is six depending on what is in store for that day. From what you wrote it sounds like this is fine, too. But I always had that nagging feeling in my mind wondering if I could be doing better. No more!

    Comment by Elizabeth — May 20, 2011 @ 12:08 pm

  2. Hi Brad. I’d always read in those muscle mags that a big reason for 5-6 protein-rich meals a day was to ensure a steady stream of amino acids to help repair and build muscle.

    People I’ve talked to told me they didn’t “get big” or “start seeing a difference” until they started adding a lot more protein to their diet via many small meals rather than 3. And, indirectly, more meals = more muscle = greater calorie needs = fat loss (when not overconsuming calories).

    Does this make sense?

    Comment by Kathleen — May 21, 2011 @ 10:14 am

  3. Hey Kathleen:

    I know there are anecdotal claims of greater muscle gains with increased feeding frequency, but this is generally not supported by research. Alan Aragon did a nice job in the critique I mentioned evaluating the evidence on this topic. Now this subject is clouded somewhat by comparisons. It does seem that one meal a day is insufficient to optimize anabolism, and a case can be made that at least three meals a day is necessary to accomplish this task. I would give the caveat that the majority of research has been performed on sedentary obese subjects, so the application to those who are participating in intense resistance training is questionable.

    Brad

    Comment by Brad — May 21, 2011 @ 10:29 am

  4. Hey Brad. Thanks for this article and providing the research. For the past year or so, I’ve been doing the small meals (5 meals) about every 3 hours. I found that when I don’t (or if it goes into 4 hours), I start getting hungry. I’m pretty active (workout about 4-5 times a week & workouts include cardio and weight training.

    Could you please elaborate on the “grazing” approach? I understand what that means when one thinks about livestock (like cows, etc), however, could you give a practical example? I’m having a hard time visualizing it. 🙂

    Thanks so much.

    Comment by JC — May 21, 2011 @ 4:09 pm

  5. Hey JC:

    I should have mentioned that another limitation of research is that results are pooled to come up with averages. Some people may have greater satiety with more frequent meals, which is likely at least partly a function of genetics. Moreover, when you eat in a regimented fashion, your body tends to adapt to that regimen. Thus, if you eat five small meals a day on a regular basis, your body will get hungry if you miss a meal. I am the same way–if I go more than several hours without food, I start craving food.

    “Grazing” is simply a catchall phrase for eating smaller, frequent meals. I generally consume 5 meals a day spaced out every three hours or so.

    Brad

    Comment by Brad — May 22, 2011 @ 6:57 am

  6. Hi Brad. Thanks for answering my questions. Great! That means I am a grazer, too! 🙂 I am going to take a moment to review that study link you included b/c I may be wrong and I’m certainly not a scientist, but I notice on days that I’m not active (I usually take a break on Saturdays and/or Sundays), I don’t need the 5 -6 frequent meals because I’m not burning as many calories–on some days, but on other days (probably based on what you just said) I’ve been “grazing” for over a year and my system is use to it.

    Also, I’m wondering if this study was done on sedentary and/or deconditioned subjects.

    Comment by JC — May 23, 2011 @ 10:24 am

  7. Could you please clarify this:
    “The fasted subjects didn’t eat for entire days at a time and still lost weight to a similar degree as those who ate daily meals.”
    I see a big difference between losing fat and losing muscle. For example I want to go from 160 pounds at 25% bodyfat to 140 pounds at more like 14% bodyfat.
    I don’t want to just “lose weight” and wind up 145 pounds and 25% bodyfat.
    In these studies where they measure losing weight — are they just going for a number on the scale or are they measuring fat loss?
    And how significant is this question (as in I suspect that under a program of diet and exercise I probably won’t lose ALL fat but I also probably won’t lose ALL muscle, but rather some combination — but how much can I influence the percentages)?

    Comment by Eric — May 24, 2011 @ 12:39 pm

  8. Hi Eric:

    The statement should have said: “…didn’t eat for *an entire day* at a time..” I made the correction in the article–thanks for pointing this out.

    The interesting thing about the intermittent fasting studies is that several have actually shown *better* retentions in lean mass. Now I should state that the methodology used to determine body comp was not ideal (they used BIA, which is much less accurate than DEXA), but nevertheless it is an interesting finding. I would also state the studies were not performed on those performing resistance training, and I would venture to guess that such a strategy would be suboptimal for those who lift. My general suggestion, as I noted in the article, would be to consume a minimum of 3 meals a day. More studies are needed to see if more frequent meals might be better in lean individuals who are involved in intense resistance training.

    Brad

    Comment by Brad — May 24, 2011 @ 4:48 pm

  9. Nice one , Brad! If there was really an increase in metabolism with TEF there would have been an term to multiply the number of times of meals in the metabolic equations.

    I didn’t see this post on facebook so I missed this one until I checked your blog.

    Comment by Anoop — May 25, 2011 @ 11:44 pm

  10. Thanks Anoop. Good point about TEF–there is no multiplier for feeding frequency!

    Brad

    Comment by Brad — May 26, 2011 @ 6:53 am

  11. […] How many meals a day should you eat? – Brad Schoenfeld […]

    Pingback by How many meals should you eat in contest prep? - Andrea Valdez — May 11, 2015 @ 3:07 pm

RSS feed for comments on this post.

Sorry, the comment form is closed at this time.