When should you eat?

Try to imagine we’ve incorporated a clock somehow.

There is no real conventional wisdom when it comes to nutrition. “Everything in moderation” and “eat healthy” seem commonsensical but then… what do either of those mean? Even sugar/hydrogenated oils/deep fried foods/preservative-laden candy bars in moderation? …And what does healthy mean? Is it a strict diet of raw food or something more like the Paleo plan or is it cutting carbs/red meat/animal products/gluten/refined white sugars? Is it a lot of protein or less than a lot? Is it lowfat dairy or no dairy or as much dairy as you please?

Our point is that every week we’re inundated with new information about what we should and shouldn’t put in our mouths (often, the information contradicts the last round of edicts). While the big trend in dieting right now is fasting–wait for all the incoming fasting books in a bookstore near you–current “conventional wisdom” involves the usual slew of Shape magazine-approved snacks like Greek yogurt and raw almonds and lean protein with vegetables, etc etc etc.

A new study, however, has found a compelling correlation between when you eat and how much weight you lose. Although parents and the like have been instructing us not to eat late for most of our lives–and we often feel the shittiest after 2 AM burritos and drunk snacking–researchers from Brigham and Women’s Hospital in collaboration with Tufts University and the University of Murcia have found that what time you eat may make a bigger difference to your diet than we previously thought…

Of 420 subjects, researchers tracked a surprising difference in weight loss. First, though, here’s how they were the same. Per ABC:

All the subjects ate and burned off about the same number of calories. They all followed a Mediterranean-style diet consisting of lean proteins, fruits and vegetables and healthy fats such as olive oil, and consumed about 40 percent of their daily calories at lunch. They all slept approximately the same number of hours each night and, when tested, their appetite and hunger hormone levels were comparable. Even their genetics were similar.

And here’s how they were different:

[S]tarting around week five, weight loss for dieters who ate their main meal after 3 p.m. began to stall and remained sluggish for the duration of the study. In the end, they lost 22 percent less weight than dieters who ate the bulk of their calories earlier in the day.

Granted, there may have been some lifestyle differences in there too (“late-in-the-day eaters did tend to be breakfast-skippers, and they showed a higher level of insulin resistance”) but apparently that’s not enough to explain away the substantial difference in weight loss.

The researchers posit that eating late can screw with the body’s internal clock, which may have consequences. Metabolism-shaped consequences. And more:

Frank Sheer, one of the study’s coauthors and an assistant professor of medicine at Harvard Medical School, explained it this way:

“The circadian system is made up of a master clock in the brain and peripheral clocks in most cells throughout the body. Normally, the master clock synchronizes all peripheral clocks, similar to the conductor of an orchestra. When meal timing is abnormal this leads to de-synchronization between these different clocks, resulting in a cacophony.”


Unfortunately, there are some obvious social hurdles eating this way presents: no dinner with the family after a day of work? No dining out with friends? Is this even possible for parents?

Still, “don’t eat the bulk of your calories late” feels like a remarkably sane piece of advice, especially compared to the avalanche of diet information we’re buried under daily.