Does Eating Late Make You Fat?

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On a typical day as a dietitian in a busy clinic, I will hear the following comment at least twice before lunchtime “I’m trying not to eat after 7pm, because I know that eating late makes you gain weight!” I never quite know what to make of this declaration. Are these folks nighttime bingers, eating large amounts of junk food out of boredom or exhaustion, or do they believe that having a sensible dinner after 7pm will, no matter the calories, turn directly into fat? I have attempted to dispute the fact that eating your biggest meal of the day (dinner for most people), when healthy and not excessive, has no bearing on whether or not someone will gain weight. I also make sure my patients know the importance of fueling their bodies throughout the day, and that skipping meals is not the answer to weight loss. According to all the research I had read, weight loss depends on the total number of calories you eat versus the amount that you expend, as long as your caloric intake is balanced and low-glycemic. Well, a new study has come out to question this long-held belief that when you eat the bulk of your day’s calories doesn’t matter. I first heard about this new study in one of my favorite blogs – the Well Blog from the New York Times. The study was first published in the The International Journal of Obesity. In this 20-week study, researchers put 420 men and women on a similar meal plan designed for weight loss. All of them ate the same total number of calories, but half the group ate the biggest meal of the day before 3pm, and half the group ate theirs after 3pm. At the end of the study, the late eaters lost significantly less weight and showed lower insulin sensitivity, which is a precursor to type 2 diabetes. This study helps shed light on a mysterious trend that I have been witnessing – that my most obese patients, many of them with type 2 diabetes, are notorious meal-skippers. They skip breakfast, and sometimes even lunch, and then eat a very large dinner. I’ve been puzzled as to the seeming correlation between skipping meals and eating late with obesity and diabetes, and now I know it may not be coincidental. I find this new research exciting – we’re finding out more and more that the equation for weight balance isn’t the old “calories in/calories out” rule. When do you eat your biggest meal? Do you have a certain meal cutoff time that works for you? Christine Weiss MS, RD is a dietitian and Bastyr University graduate who counsels people dealing with food allergies, diabetes and digestive issues. She enjoys working with Zing Bars to raise awareness about healthy living through online media. She can be found at Eating It Up online.