Of course, it matters what you eat. Nutrition is an essential part of the “get lean” and healthy equation. But what about meal frequency – how often you eat? Fitness trainers sometimes tell clients to eat smaller meals throughout the day, every 2 to 3 hours, to help with fat loss and improve body composition. But what does science say about the issue? Should you eat more meals to improve body composition – or does it matter?
Do More Frequent Meals Boost Metabolism?
Your resting metabolic rate is the rate at which your body burns energy when you’re not actively exercising and you haven’t just eaten a meal. It corresponds to calories you burn when you’re simply resting. This component of your metabolism makes up 60% of the calories you burn each day. Another component of your metabolism is the energy you expend during exercise. Finally, there’s the thermic effect of food, corresponding to the additional calories you burn after eating a meal or snack. Your body has to expend extra energy to digest, process, and metabolize what you eat. This normally accounts for only a small part of your total energy expenditure, about 10%.
The idea behind frequent meals being favorable for fat loss and body composition comes from the additional spike in the metabolic rate you get each time you eat. If you eat every few hours, your metabolism increases more often throughout the day due to the thermic effect of food. So, it should add up to more calories burned, right? Unfortunately, this doesn’t necessarily hold up in practice.
A group of researchers analyzed a variety of studies that looked at meal frequency and energy expenditure over 24 hours. What they found was 24-hour energy expenditure was similar regardless of whether participants ate one meal a day or 10 times a day when they consumed a similar number of calories. While it’s true that you get a brief spike in energy expenditure after a meal, a small meal gives rise to a small increase in the metabolic rate while a larger meal elicits a bigger one. So, there’s actually no real difference in total energy expenditure with small, frequent meals versus larger ones. What’s more important, in terms of the thermic effect of food is the number of calories you eat.
Impact on Body Composition
While eating more frequent meals might not boost 24-hour energy expenditure, can it lead to greater weight loss by other mechanisms such as increased activity level or decreased appetite? Some observational studies show an inverse link between meal frequency and the likelihood of being overweight, but observational studies are fraught with problems, including under-reporting of food intake.
When you look at the majority of controlled, experimental studies, meal frequency, even when calories are held constant, has no impact on body composition in overweight and normal weight individuals. One exception may be the preservation of lean body mass in athletes. Some studies show that eating more frequent meals reduces the loss of lean body mass when athletes adopt a low-calorie diet. There’s also some evidence that more frequent meals boost fat loss in athletes. So, greater meal frequency could potentially have a positive impact on body composition among physically active people but not sedentary individuals.
Effects of Meal Frequency on Appetite
What about appetite? That’s where you might expect meal frequency to have the greatest benefit and it does, based on several studies. In one study involving lean, healthy males, eating more frequent meals led to greater satiety and appetite control. Another study showed individuals who ate a single meal a day experienced more hunger than those who ate a similar number of calories spread over three daily meals. The majority of evidence suggests that under conditions of calorie restriction to lose weight, eating more frequently helps with appetite control.
Is Eating More Frequently Better for Your Health?
Some experts tout the health benefits of intermittent fasting, eating meals within a narrow time frame of 8 to 12 hours and fasting the rest of the time. While this may have health benefits, meal frequency studies show improved markers such as insulin sensitivity, total cholesterol, and LDL-cholesterol. Some studies also show fasting improves insulin sensitivity in men but not women. Short-term fasts may also reduce oxidative stress and the ability of cells to repair.
The Bottom Line
Meal frequency doesn’t have a significant impact on body composition in sedentary people when you control for total calorie intake and it doesn’t increase 24-hour energy expenditure, based on the majority of studies. Where it may be helpful is if you’re restricting calories to lose weight and you’re also strength training. Eating more frequent meals, in this case, may help you retain more lean body mass as you reduce calorie consumption. It may also help with appetite control when you’re trying to lose weight. Also intriguing are studies showing eating more frequently enhances health markers, like cholesterol and reduces insulin levels. Yet, there’s also some evidence that intermittent fasting improves some health markers as well.
All in all, the best approach is to focus on the quality of the calories you eat and be mindful of portion sizes. It’s less important when or how often you eat each meal or snack. If you have problems with appetite control, eating more frequently may help you avoid cravings that could lead to munching on the wrong foods. Regardless, be sure to include a source of protein with every meal or snack for added satiety. As far as frequency goes, find out what works for you based on your schedule. Be sure that you eat a small protein and carb meal after a workout to help your body refuel. Don’t get too caught up in how many times to eat each day – it won’t have a huge impact on your weight or body composition.
References:
Br J Nutr. 2010 Apr;103(8):1098-101. doi: 10.1017/S0007114509992984. Epub 2009 Nov 30.
Nutr Rev. 2009 Jul;67(7):379-90. doi: 10.1111/j.1753-4887.2009.00204.x
Journal of the International Society of Sports Nutrition20118:4. DOI: 10.1186/1550-2783-8-4.
Br J Nutr. 2008, 99 (6): 1316-21. 10.1017/S0007114507877646.
Mol Cell Endocrinol. 2015 Dec 15;418 Pt 2:153-72. doi: 10.1016/j.mce.2015.09.014. Epub 2015 Sep 16.
Authority Nutrition. “10 Evidence-Based Health Benefits of Intermittent Fasting”
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