Looks like the old saying, “You are what you eat,” needs a bit of a redo. In fact, it seems that you are what you eat and when you eat. New studies are showing why so many have trouble derailing their late night cravings and subsequent eating and what that actually does to weight loss efforts. However, going cold turkey to try to get back on track isn’t the key.
How to avoid weight gain from late night eating
“For years, we said a calorie is a calorie no matter when you consume it,” says dietitian Joy Dubost, a spokeswoman for the Academy of Nutrition and Dietetics. “I don’t know if we can say that anymore, based on the emerging research. The timing of a meal may potentially have an impact.”
Studies tend to show that when food is consumed late at night — anywhere from after dinner to outside a person’s typical sleep/wake cycle — the body is more likely to store those calories as fat and gain weight rather than burn it as energy, says Kelly Allison of the University of Pennsylvania School of Medicine’s Center for Weight and Eating Disorders.
“The studies suggest that eating out of our normal rhythm, like late at night, may prompt weight gain” and higher levels of blood sugar, which can raise the risk of chronic disease, Allison says.
Not enough research on what prompts weight gain has been done, Allison says, to determine whether timing is as important as — or even more important than — the types or amounts of food often consumed at night. People tend to choose more highly palatable items — sweet and salty foods, which tend to be more caloric — when they’re tired and have restrained themselves all day, Allison adds. And night-shift workers tend to overestimate how many calories they need to stay awake while on duty.
The main meal
Two recent studies have shed new light on the potential impact of timing. In a study of 420 overweight or obese people published in 2013, those who ate their major meal after 3 p.m. lost less weight during a 20-week weight-loss program than those who ate that main meal before 3 p.m. — even when the amount they ate, slept and exercised was the same.
In a subsequent small study of healthy women published this year, Garaulet and her team showed that when participants ate lunch after 4:30 p.m., they burned fewer calories while resting and digesting their food than they did when they ate at 1 p.m. — even though the calories consumed and level of activity was the same.
What’s more, when the participants ate late, they couldn’t metabolize, or burn off, carbohydrates as well as when they ate earlier. They also had decreased glucose tolerance, which can lead to diabetes. (The two-week study did not track whether the women gained or lost weight.)
Dining like kings
Most Americans spurn the adage to “eat breakfast like a king, lunch like a prince and dinner like a pauper.” U.S. adults consume 17 percent of their day’s calories at breakfast, 24 percent at lunch and 34 percent at dinner, according to the USDA’s “What we eat in America” survey.
It may be the pace of work life, which leaves room for little more than a quick breakfast and lunch during the typical weekday.
But circadian rhythms — the internal body clock that regulates sleep and other cycles based on light and darkness — may also be a factor. In a small study published in 2013, a group of non-obese adults stayed in a dimly lit area for 13 days, got plenty of sleep and consumed identical meals at even intervals throughout 24-hour periods. Despite that regularity, they still reported being substantially hungrier at 8 p.m., than they were at 8 a.m. They also had more cravings for sweet, salty and starchy foods in the evening.
The Oregon Institute’s Shea, who co-authored this study, suggests that evolution may be at work. For our primal ancestors when food was scarce, he hypothesizes, “one of the most [evolutionarily] efficient things to do in the evening was to eat. That’s when the body can store energy as fat and glycogen, so that you’re ready for what might happen the next day without having to immediately replenish calories by eating.”
Hormones may also be driving us to eat late, says Pamela Peeke, an assistant professor of medicine at the University of Maryland School of Medicine.
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