Do frequent meals increase your metabolism? You've probably heard it before - in order to lose bodyfat, you need to eat every few hours to increase your metabolism and augment fat loss. But how true and valid is this statement? Let's discuss.
The answer is no. Whilst eating regularly through the day can help stabilise blood sugar levels and prevent binging, breaking your caloric intake into divided meals during the day has NO impact on metabolic rate.
There are 5 main factors that affect your overall energy expenditure throughout the course of 24 hours (24EE):
1. Your Basal Metabolic Rate (BMR): the calories you expend at rest to keep your heart beating, lungs breathing etc.
2. The Thermic effect of the food you eat (TEF): the calories your body utilises to digest, assimilate and breakdown food
3. Exercise thermogenesis (Eex): the calories
4. Non-exercise activity thermogenesis (NEAT): the calories expended from unexpected movement
5. Cold thermogenesis (CT): the calories you spend when exposed to colder temperatures
This can be equated as following:
24EE = BMR + TEF + Eex + NEAT + CT
By maintaining the caloric intake, increasing your meal number will not directly affect Eex, NEAT and CT. This leaves us with BMR and TEF to evaluate the effect of meal numbers on metabolic rate.
Other than exercise, the main driver of caloric expenditure in a day is your fat-free mass (your total body mass without the fat - muscles, organs, skins, bones etc). The larger your fat-free mass, the higher the calories you burn at rest (BMR). This essentially means the majority of energy expended over a 24 hour period is determined by your BMR, so meal frequency would not increase your metabolism. This has been shown in numerous scientific journals such as Munsters & Saris (2012) and Heilbronn et al., (2005).
Next, let's address the thermic effect of food. It is true that digesting a meal raises your EE (energy expenditure) slightly. However, eating 3 meals at 600 calories will cause the same thermic effect as eating 6 meals of 300 calories. Again, literature from Taylor & Garrow (2001) shows it's the total amount of food consumed that determines the amount of calories expended for food processing and assimilation.
To wrap up, eating more frequently during the day DOES NOT increase metabolism. It can certainly balance blood sugar levels, decrease the risk of binging, make eating large quantities of food easier and reduce lethargy from large meals, but breaking your foods down into 6 meals a day will not raise metabolic function or increase fat oxidation.