Is it really important to eat six meals a day instead of three larger ones? Does it make a difference in terms of weight loss?
One common myth is that smaller meals somehow “fire up” your metabolism compared to eating fewer (larger) meals. Not true–here’s one study that was done comparing big meals to small meals:
A study was conducted to investigate whether there is a diurnal pattern of nutrient utilization in man and how this is affected by meal frequency to explain possible consequences of meal frequency for body weight regulation. When the daily energy intake is consumed in a small number of large meals, there is an increased chance to become overweight, possibly by an elevated lipogenesis (fat synthesis and accumulation) or storage of energy after the meal. Thirteen subjects, two males and eleven females, were fed to energy balance in two meals per day (gorging pattern) and seven meals per day (nibbling pattern) over 2-day intervals. On the second day on each feeding regimen, the diurnal pattern of nutrient utilization was calculated from simultaneous measurements of oxygen consumption, carbon dioxide production and urinary nitrogen excretion over 3 h intervals in a respiration chamber. A gorging pattern of energy intake resulted in a stronger diurnal periodicity of nutrient utilization, compared to a nibbling pattern. However, there were no consequences for the total 24 h energy expenditure (24 h EE) of the two feeding patterns (5.57 +/- 0.16 kJ/min for the gorging pattern; 5.44 +/- 0.18 kJ/min for the nibbling pattern). Concerning the periodicity of nutrient utilization, protein oxidation during the day did not change between the two feeding patterns. In the gorging pattern, carbohydrate oxidation was significantly elevated during the interval following the first meal (ie from 1200 h to 1500 h, P less than 0.01) and the second meal (ie from 1800 h to 2100 h, P less than 0.05). The decreased rate of carbohydrate oxidation observed during the fasting period (from rising in the morning until the first meal at 1200 h), was compensated by an increased fat oxidation from 0900 to 1200 h to cover energy needs. In the nibbling pattern, carbohydrate and fat oxidation remained relatively constant during the active hours of the day.1
There are several similar studies out there, and all of them stating the same thing: what really matters is overall calorie balance–how many calories you eat vs how many you use. There is no metabolic advantage to eating several smaller meals instead of a few larger ones.
So, are there any advantages to eating smaller meals? Maybe.
The effectiveness of most diets come down to compliance. In other words, some will find it easier to stick to a diet if they are eating more frequently. Imagine I’m restricting my caloric intake to 2,000 calories a day. Eating five 400 calorie meals/snacks may be easier than eating two 1,000 calorie meals.
But the potential disadvantage here is the hassle of preparing this many meals/snacks per day. This may make frequent, small meals impractical for some.
The second theoretical advantage would be a possible reduction in stomach size. Studies suggest the stomach expands according to our eating habits. Binge eaters, for example, have a greater gastric capacity than those who do not binge eat:
One function of the stomach is as a reservoir for food; hence, the stomach’s capacity may limit the amount of food ingested. A stomach with a large capacity has been associated with bigger test meals. We compared the stomach capacity of three groups of women: normal (n=10), obese (n=11), and bulimic (n=10). Following an overnight fast, gastric capacity was estimated by filling a gastric balloon with water at 100 ml/min, with pauses for measuring intragastric pressure. One estimate was based on the maximum volume the subject could tolerate as indicated by a maximal rating of abdominal discomfort. Another estimate was based on the volume required to produce a given rise of intragastric pressure, 5 cm H(2)O. A third related measure was based on a maximal rating of fullness. Based on these estimates, the gastric capacity of the bulimics was the largest, with the obese subjects intermediate. We then separated the obese subjects according to whether they reported binge eating (n=6) or not (n=5). The gastric capacity of the binge-eating subset was similar to the bulimics, and the nonbinge-eating subset was similar to the normals. Thus, gastric capacity appears more related to binge eating behavior than to body weight.2
Those who binged on larger meals have a greater gastric capacity. I wonder if smaller meals could help “retrain” the stomach to feel full with less food. It’s just a guess, but perhaps it is one worth considering.
Conclusion:
There is no metabolic advantage to eating smaller, frequent meals, so don’t panic if you can’t eat six times a day (as some trainers may prescribe). You should be able to reach your weight loss goals using other strategies. I’ve found intermittent fasting to be more practical for me, but everyone is different. Just remember the most important factor is an overall negative calorie balance.
References:
1. Eur J Clin Nutr. 1991 Mar;45(3):161-9. Influence of the feeding frequency on nutrient utilization in man: consequences for energy metabolism.
2. Physiol Behav.2001 Nov-Dec;74(4-5):743-6. Gastric capacity in normal, obese, and bulimic women.
