Digesting the food you eat can raise your metabolism; this is called the thermic effect of food.
Increasing meal frequency was believed to help further raise your metabolism by elevating your thermogenesis more often. However, studies showed that this thermic effect was small and insignificant and eating frequently didn’t really help in weight loss. Even on a calorie-controlled diet, eating frequently didn’t appear to favorably change body composition either. So why do nutritionists advise on frequent eating?
Reason #1. Maintain Your Weight
You don’t eat anything during the day, you get home and have a feast dinner… Can you relate? When you don’t eat during the day or only have one meal, you get more hungry, leading to overeating on your meals. Overeating contributes not only to poor digestion which is the major cause of heartburn but also weight gain. Studies showed that those who skipped meals during the day tend to gain belly fat on the long run.
Eating every 2 to 3 hours will control your hunger and portion sizes, keeping you away from those high calorie meals.. and therefore maintaining your weight!
Reason #2. Keep Your Health in Check
Skipping meals have been positively associated with dyslipidemia (abnormal blood lipid levels), high blood pressure and diabetes; while eating frequently was shown to positively affect blood markers of health (like triglycerides and LDL cholesterol, the bad cholesterol). Keeping blood markers of health in check is important for reducing disease risk.
Also, eating frequently positively effect certain hormones involved in weight loss (like insulin that regulates blood sugar and fat storage). When you eat small meals every 2 to 3 hours, your blood sugar levels stay steady avoiding spikes in insulin.
Reason #3. Preserve Your Muscle Mass
Eating frequently helps you preserve your muscle mass if you exercise regularly AND you are on caloric deficit to lose body fat; but this is true only if your protein levels are adequate.
A study tracked 2 groups of boxers consuming the same amount of calories (1200kcal) over a period of 2 weeks. One group had 2 meals of 600 kcal and the other group had 6 meals of 200 kcal. Results showed that both groups lost the same amount of weight; but those who ate twice daily lost more muscles and less fat than those eating 6 times per day.
La Bounty, Paul M., et al. “International Society of Sports Nutrition position stand: meal frequency.” J Int Soc Sports Nutr 8.4 (2011).