When You Eat Is Why You're Fat
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By Ariel Schwartz
At this point, it's practically conventional wisdom: If you skip breakfast, you're going to have trouble losing weight, probably because you overeat later in the day (the Mayo Clinic offers a handful of other reasons why). A new study in the International Journal of Obesity takes the notion of timing and weight loss even further, claiming that when you eat meals throughout the day affects how easily you drop pounds.
The study, performed by researchers from Brigham and Women's Hospital, the University of Murcia, and Tufts University, split 420 overweight participants into groups of early and late eaters. All of the participants followed a weight-loss diet, but half had lunch before 3 p.m., and half had lunch afterwards. It's culturally important that the study focused on lunch; all the participants lived in Spain, where it's the main meal of the day (and where 40% of the day's calories are eaten).
Even though diet, energy intake, estimated energy expenditure, appetite hormone levels, and sleep duration were basically the same for all participants, the people who ate late lunches lost less weight--and lost it at a slower rate, too. The participants dropped weight at the same pace for the first five weeks of the 20-week study, but after that, those eating later saw their weight loss sputter to a halt. By the end of the study, they had lost 22% less weight than the earlier eaters.
The study summary points out that the later eaters often skipped breakfast and had higher insulin resistance, but not enough to explain the dramatic results.
And so, the authors conclude, "Eating late may influence the success of weight-loss therapy. Novel therapeutic strategies should incorporate not only the caloric intake and macronutrient distribution--as is classically done--but also the timing of food." In many parts of the world where dinner is the main meal of the day, eating earlier isn't so easy. But for anyone serious about weight loss, it's worth considering how timing might affect you.
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Copyright 2013 by Fast Company. Reprinted with permission.
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7 Comments
Add CommentPlease tell me that the participants were assigned RANDOMLY to the early and late eating groups! The comment about late eaters skipping breakfast makes me think that the participants were split according to existing behavior which carries with it the likelihood that other, uncontrolled, behaviors may be correlated with their preferred lunch time. Does no one remember the infamous coffee-cancer study that failed to control for smoking?
Reply | Report Abuse | Link to thisAlas from what I've read about this research (couldn't get access to the original, alas) the 420 participants were split based upon their preferred timing of lunch (i.e. before 3pm or after 3pm).
Reply | Report Abuse | Link to thisAgreed on your point that there may well be confounding variables at work here, although a 22% differential in weight loss is significant.
I have not eaten breakfast in decades. In fact I usually end up with issues later in the day with stomach pain if I do eat before 10. Usually I just eat once a day and guess what, I lose weight. I eat more than once, I will gain it.
Reply | Report Abuse | Link to thisIt has nothing to do with time of day or anything else other than eating too much in general, eating factory processed foods not that I am a vegen at all, meat mostly for me, however a previous SA article had evidence that processed foods have calories more efficiently than say a carrot. I dont remember the exact numbers but the processed foods get closer to 100% of being digested by the body, where a carrot mught be closer to 60% or something like that. The point being what you eat and the amount of it is the biggest effect. The only way to ensure weight loss or control is to not eat more than your body uses. If you are lazy, then dont suck down 3000 calories a day, if you want to eat 3000 calories a day, better be in the gym or something to burn the calories. The body is designed to store energy. Take in too much, especially carbs and sugars, the body will turn that into fat cells by design. Think of ancestors living hand to mouth off the land. In the summer all of the high calorie sugars and available, gorge on that stuff so the body can store some of it because the long frozen winter is likely to be mostly meat.
This article is ridiculous with its claim of time of day and the cause is because people eat more when they finally do eat. It has nothing to do with the time of day and everything to do with lack of discipline.
Another good article for "People" magazine, but what's it doing in "Scientific American"?
Reply | Report Abuse | Link to thisUnscientific American, how did a reasonable ""Eating late may influence the success of weight-loss therapy." basic conclusion turn into the misleading title "When You Eat Is Why You're Fat"?
Reply | Report Abuse | Link to thisAbout half of all of the titles of articles--and usually the contents--that show up in my SciAm widget/tool on my Google home page are now salacious, misleading, sensationalistic, or are just plain wrong.
I started reading Scientific American in 1966 and the decline has been very noticeable.
--Tim May
Bravo! Couldn't agree with you more! Those third variables may not make for sexy reading, but a lot of us scientific lay people still want to hear about the rigor that did (or perhaps did not) go into these kinds of studies.
Reply | Report Abuse | Link to thisWow, I respond to the first comment about a seeming lack of rigor in quant research (or reporting on quant research), and then I find a a reader blasting the article based on a sample size of 1.
Reply | Report Abuse | Link to thisPriddseren, just because it works for you doesn't mean that's the norm. That's why we use quantitative measurement in these kinds of studies - the quantity of measurements taken is as important as the quality of the measurements taken.
Your metabolism may be atypical. Your vegan diet certainly is (i.e. most people aren't vegan). A thousand other factors unique to you may impact your weight gain or loss. This is why we base our knowledge on studies of groups rather than on studies of individuals.