QUESTION; I was wondering if there is any evidence as to whether the traditional three meals per day is better than, for example, one or two meals per day. Or is it better to eat several meals per day? If you are not hungry and wanting to lose weight, is there any drawback to skipping a meal (assuming that you don't overdo on the next meal)?
There is really little to any well-done credible science to support the theory that there is a difference between eating 3-5 meals per day, 1-2 meals per day or just consuming regular small snacks all day. Likewise, the time of day that you consume your food, does not matter either.
While you often here of the advantages of several small meals over less larger meals, as long as total calories are restricted, there is not really a big difference and some recent studies in animals have shown that less frequent meals may have some advantages. There are studies being done where the animal are fed every other day (EOD) or once a day.
Years ago, they said it helped lower cholesterol levels, triglycerides, blood sugar, insulin, etc. However, most science organizations today will no longer make these claims, as there was and is little if any evidence to support them.
The claims that eating frequently keeps your metabolism raised is false as the increase in metabolism to digest food is only around 10% of the total calories ingested. So if you consume 300 calories, you may "burn" 30 more than if you did not consume anything, but you end up with a net gain of 270 calories. Taking in a net 270 calories to raise your metabolism by 30 calories, would not be beneficial in regard to energy balance.
One of the problems with eating less frequent meals is that we live in a society where food is inexpensive, calorie dense and everywhere. Therefore, skipping meals and saying "no" to the food around us, can be difficult. In addition, some people find that if they eat less often they have trouble controlling the amounts they eat when they do eat.
In today's unhealthy culture, there may be some psychological and sociological advantage to frequent small meals of healthy foods. For many, this may be an important issue as they may find small frequent meals gives them better "control.”
Remember, many people see this lifestyle as one that takes a lot of discipline and effort. To then add in reducing meal frequency, is to add in more discipline and effort which may make success more difficult while not adding in any additional benefit.
So, in the end, because there is really little evidence anywhere that any of these minor details will matter, what does matter is to do which ever one helps you with the best compliance & adherence over time. :)
However, for those interested in the discussion....
In this very recent study (1), more frequent meals was associated with better long term weight loss maintenance. And, this is from one of the longest ongoing databases of long-term successful weight loss and maintenance.
The study concluded, "Eating frequency, particularly in regard to a pattern of three meals and two snacks per day, may be important in weight loss maintenance."
In the second one below (2), reduced meal frequency had a negative effect on blood sugars and, most surprising, this was done in healthy, non-overweight subjects while keeping caloric intake the same between groups.
Of course, the reason for this may be simply that if the same amount of food is being consumed much less often, the meals are going to be of a much greater size and volume to accommodate the same amount of calories. This can impact gastric volume and emptying, which in-turn can influence blood glucose and insulin levels. Now, to be fair, in this study, they used one meal a day, so this potential impact would have been greatly accentuated and may not be reflective of a more rational reduced meal frequency.
So, the real benefit to reduced meal frequency may be just the overall reduction in calories and not just the reduction in the frequency of the meals.
I see this so often in patients.
They follow one diet for a while and lose some weight and then plateau and get frustrated. So, as a result, they start following a new diet that has a different set of rules, often related to meal frequency (or some other related or similar rules) and they suddenly start doing better and so think it is due to the change in meal frequency (or other rules). However, the real change that happened, which they often do not see, is that by following these new rules, they reduced their overall caloric intake.
I have seen this happen time and time again in both those who move to more frequent meals (ie, from 2-3 meals/day to 4-6 meals/day) and in those who move to less frequent meals (from 4-6 meals/day to 2-3 meals/day). Now, the real irony in all of this is that those who go to a more frequent meal pattern are thoroughly convinced that more frequent meals is the key issue and those going to a less frequent meal pattern are thoroughly convinced that less frequent meals is the key issue. :)
However, some people just can't maintain a meal plan with fewer meals and some just can't maintain a meal plan with more frequent meals. I am one of the latter, and so, I keep a more limited meal plan but would not insist on that for someone who felt more comfortable with more frequent meals as long as the overall dietary and nutritional pattern is the same.
To continue, there was a second paper published on these same subjects (which was a double cross over design, so a very well done study) and the found significant increases in total cholesterol, LDL cholesterol and in blood pressure, compared to when they ate more frequent meals. These findings were published in the April 2007 issue of the American Journal of Clinical Nutrition. However, remember, this was from one very large meal per day with the exact same calories as the more frequent meals.
This older study (3) found that "Although there was no difference in change of body weight by food restriction between the two groups, the decrease in lean body mass (LBM) was significantly greater in the 2M [meals per day] group than in the 6M [meals per day] group.
A more recent study showed (4) this exact same effect in mice
And from the recent position part of the International Society of Sports Nutrition position (5)
"Admittedly, research to date examining the physiological effects of meal frequency in humans is somewhat limited. More specifically, data that has specifically examined the impact of meal frequency on body composition, training adaptations, and performance in physically active individuals and athletes is scant. Until more research is available in the physically active and athletic populations, definitive conclusions cannot be made. However, within the confines of the current scientific literature, we assert that:
1. Increasing meal frequency does not appear to favorably change body composition in sedentary populations.
2. If protein levels are adequate, increasing meal frequency during periods of hypoenergetic dieting may preserve lean body mass in athletic populations.
3. Increased meal frequency appears to have a positive effect on various blood markers of health, particularly LDL cholesterol, total cholesterol, and insulin.
4. Increased meal frequency does not appear to significantly enhance diet induced thermogenesis, total energy expenditure or resting metabolic rate.
5. Increasing meal frequency appears to help decrease hunger and improve appetite control."
This most recent study found a slight advantage to men with a more frequent meal pattern but not for women. (6)
So, as I said above, in the end, the most important issue is to follow the guidelines of healthy eating which include:
- Center your plate and your diet around minimally processed plant foods.
- Enjoy foods as close to "as grown in nature" with minimal processing that does not detract
from the nutritional value &/or add in any harmful components.
- Follow the principles of calorie density.
- Avoid/minimize the use of added salts, oils/fats and sugars.
- Choose a variety of food in each of the recommended food groups.
Whether someone does this in 3 meals vs 5 meals vs 1 meal, may be less important than their total calorie intake and overall food choices and would be a fine detail that would be up to the individual based on which method helps them incorporate these more important principles.
Some people just can't maintain a meal plan with fewer meals and some just can't maintain a meal plan with more frequent meals. I am one of the latter, and so, I keep a more limited meal plan but would not insist on that for someone who felt more comfortable with more frequent meals as long as the overall dietary and nutritional pattern is the same.
(1) Eating Frequency Is Higher in Weight Loss Maintainers and Normal-Weight Individuals than in Overweight Individuals. Journal of the American Dietetic Association. Volume 111, Issue 11 , Pages 1730-1734, November 2011.
2) Impact of reduced meal frequency without caloric restriction on glucose regulation in healthy, normal-weight middle-aged men and women. Metabolism. 2007 Dec;56(12):1729-34.
3) Effects of meal frequency on body composition during weight control in boxers. Scand J Med Sci Sports. 1996 Oct;6(5):265-72.
(4) Obesity (Silver Spring). 2010 Mar;18(3):456-62. Epub 2009 Oct 1.
Mild calorie restriction induces fat accumulation in female C57BL/6J mice.
(5) International Society of Sports Nutrition position stand: meal frequency. J Int Soc Sports Nutr. 2011 Mar 16;8:4.
6) Daily eating frequency and cardiometabolic risk factors in young Australian adults: cross-sectional analyses. Br J Nutr. 2012 Sep;108(6):1086-94. Epub 2011 Dec 16.