Is eating several small meals a day is superior to a few large meals a day?
Despite being a highly impractical meal pattern for many people, this is by far the most common diet myth around; not only in the fitness community, but also in the mass media. As a consequence, it’s also the hardest diet myth to kill, as it’s being perpetually kept alive and repeated ad infinitum by the supplement industry, nutritionists that can’t put the research into proper context and people that just keeps repeating what the others are saying. Let’s look at what the actual studies can tell us about this topic.
Meal frequency and TEF
You’ve probably heard that eating smalls meals throughout the day ‘stokes the metabolic fire’ or is the ideal way to eat in order to control cravings and blood sugar; as consequence, this should also be the ideal way to eat for fat burning purposes. This belief is partly based on a gross and blatantly incorrect interpretation of research concerning TEF (Thermic Effect of Food).
Besides body weight, activity patterns and genetics, TEF is part of the equation that determines your metabolic rate for each given day. Paradoxically, ingesting energy costs energy and TEF is the increase in metabolic rate above basal conditions due to the cost of processing food for storage and use (ref). Simply put, every time you eat, the body expends a certain percentage of energy just to process the food you just ate. TEF varies between the macronutrients; protein is given a value of 20-25%, carbs 5% and fat 2-3% (ref). In a mixed diet, TEF is usually estimated to 10% of the calorie intake.
So, every time you eat, TEF comes into play and your metabolic rate increases in response to the meal you just ate. The problem here is that the research has been presented in such a way that it has lead people to believe that the net effect of TEF of several small meals would be greater than that of a few, large meals.
You see, TEF is directly proportional to the calories contained in the meal you just ate (ref). Assuming a diet of 2400 calories, with the same macronutrient composition, eating six small meals of 400 calories or three big meals of 800 calories, TEF will be exactly the same at the end of the day. The only thing that will differ between each meal pattern is the pattern of the spikes; six small meals will equal six small spikes in metabolic rates, while three big meals will equal three big spikes.
So, while eating several small meals a day will per definition ‘keep the metabolic furnace burning’, three big meals will ‘keep the metabolic furnace blasting’.
How about fat burning? As researchers have found, substrate metabolism is largely dictated by the meal you just ate and the macronutrient composition of your diet - how you split your meals have no consequence for the amount of fat oxidized at the end of the day (ref). Simply put, if you eat six small meals throughout the day, you will store and burn less fat between the meals compared to three meals a day, while you will store and burn more fat with three meals a day. Substrate metabolism will be different, but the net effect will be the same on either meal pattern.
Note that I say ‘store’, because fat storage and fat burning is an ongoing process – with six small meals you will store less AND burn less, and with three meals a day you will store more AND burn more. This is important to remember, as it can and has been twisted into ‘you will store more fat with three meals a day’. Sure, if you measure fat storage on a meal per meal basis, which is insane, but on the other hand you will burn more fat in between the meals. Whether you store or lose body fat at the end of the day is a consequence of intake minus expenditure; not meal frequency.
In conclusion, different meal splits have no effect on metabolic rate or fat metabolism.
I must admit that I’m a bit amazed at how people keep missing the boat when it comes to meal frequency and TEF. This myth is also prevalent in the minds of many professionals, which is even more confusing. The research is there, right in front of your eyes if you know where to look, and there’s been several large scale, meticulously controlled and well designed studies on the topic of meal frequency and TEF. And still, people keep believing that several small meals a day will increase your energy expenditure beyond what fewer, large meals will do.
Then again, the powers that be, in this case the supplement industry, loves the fact that the myth is being kept alive. What do people eat when they are being told that they should eat six meals a day? Well, it sure isn’t six home cooked meals. Rather, people are downing meal replacement products, protein shakes and bars in between the main meals. This is a billion dollar industry that is partly being kept alive by erroneous beliefs. Bodybuilding and fitness magazines usually have no interest in presenting accurate information about the topic, as they derive a large part of their financing from supplement ads. In fact, many magazine writers have a vested interest in keeping the myth alive as well, themselves being owners of supplement companies that make millions out of selling protein powders and meal replacement bars.
Is a high frequency meal plan ever warranted? Sure, if your energy expenditure is extremely high, it would probably be a lot more comfortable to consume your calories in several meals rather than a few very large ones. The 300 lbs off-season bodybuilder or endurance athlete that needs 5-6000 calories a day to maintain body weight would be better advised eating 6 meals of 1000 calories rather than 3 meals with 2000 calories. Some other instances, such as some teenagers having a hard time putting on weight, would also warrant a high frequency meal plan simply because it would be hard getting all the calories in three meals.
However, these cases represent a minority of people. Getting enough calories in few meals doesn’t seem to be a problem for the great majority, and going by the feedback the 16-8 system has been getting, it’s definitely a more comfortable way to eat for many people.
Studies cited for this excerpt (in no particular order)
Denzer CM - The effect of resistance exercise on the thermic effect of food - International Journal of Sport Nutrition and Exercise Metabolism
Bellisle F et al. Meal frequency and energy balance. Br J Nutr. 1997 Apr;77 Suppl 1:S57-70.
Westerterp KR et al. Influence of the feeding frequency on nutrient utilization in man: consequences for energy metabolism. Eur J Clin Nutr. 1991 Mar;45(3):161-9
Taylor MA , Garrow JS. Compared with nibbling, neither gorging nor a morning fast affect short-term energy balance in obese patients ina chamber calorimeter. Int J Obes Relat Metab Disord. 2001 Apr;25(4):519-28.
Jones PJ et al. Meal frequency influences circulating hormone levels but not lipogenesis rates in humans. Metabolism. 1995 Feb;44(2):218-23.