How many meals a day should you eat?

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In response to a recent reader e-mail:

My question is the following: is it better to eat three meals per day or is it better to eat several small meals throughout the day? I am currently weight training a few times per weeks and I am also trying to lose some weight. Ideally, I want to lose some fat while also gaining some muscle.

This debate has bounced back and forth since at least the 1960s (when some key papers were published in Lancet and the American Journal of Clinical Nutrition). The latest take comes in a study by researchers at the University of Ottawa that will appear in a forthcoming issue of the British Journal of Nutrition. The basic idea is that eating more frequently might keep you feeling more full, possibly by preventing big swings in the gut hormones that influence hunger:

Increased feeding frequency has often been proposed to convey favourable effects on body weight, adiposity and energy intake, but controversy persists. It has been hypothesised that the favourable effect of increased meal frequency (MF) could emanate from a more sustained release of gastrointestinal hormones; however, more studies are needed to confirm this postulation.

In this study, they put 16 obese volunteers on diets with identical caloric deficits for eight weeks. Half of them ate three meals a day, while the other half at three meals plus three snacks. The results: no difference. Or, in science-ese:

The premise underlying the present study was that increasing MF would lead to better short-term appetite regulation and increased dietary compliance; furthermore, it was hypothesised that these predicted beneficial effects of increased MF could have resulted from more favourable gut peptide profiles, potentially leading to greater weight loss. Under the conditions described in the present study, all three hypotheses were rejected.

Now, only a fool would think that, after nearly half a century of conflicting results, the newest study must be the truest. This is just one more data point. But it suggests to me that there isn’t compelling evidence either way — so the choice is up to you. Personally, I snack.

(Thanks to Jim for the question, and to this NYT article for the pointer.)