Doctor’s Tip: Overweight? When you eat matters

Dr. Greg Feinsinger
Doctor’s Tip
Dr. Greg Feinsinger.

Michael Greger, M.D. is one of the most respected people in the field of nutrition. He has the nonprofit, and wrote the popular book “How Not to Die.” In December he came out with a second book: “How Not to Diet.”

There’s no question that what we eat, how much we eat, and how much we exercise play major roles in determining our weight. But did you know that when we eat also plays a role? The Academy of Nutrition and Dietetics says: “Potentially consuming more energy earlier in the day, rather than later in the day, can assist with weight management.”

There are now many well-done human studies showing that skipping breakfast is associated with being overweight, in spite of the fact that in general breakfast-skippers eat fewer calories per day than do breakfast-eaters. Here’s an interesting study: U.S. Army researchers had two groups of people eat one meal a day — one group ate only breakfast and the other group only dinner. Both groups ate the same number of calories and neither group was allowed to exercise. The breakfast-only group lost two pounds more per week than did the dinner-only group.

In another study, done by Israeli researchers, overweight and obese women were randomized into one of two groups, each of which got the same number of calories per day. One group was given a 700- calorie breakfast, a 500-calorie lunch, and a 200-calorie dinner. The other group was given a 200-calorie breakfast, a 500-calorie lunch, and a 700-calorie dinner. The group that got the biggest breakfast lost twice as much weight as the other group.

We used to think the phenomenon of breakfast-skippers gaining weight was due to their metabolism slowing down, but now we know that’s not the case. It turns out that the relatively new science of chronobiology — the study of our bodies’ natural rhythms — contains the explanation.

It’s complicated, but here’s the simplified explanation of how this works: It takes about 50 percent more calories to digest food you eat in the morning than the same amount of food later in the day. As Dr. Greger explains, when we eat in the morning “our bodies are using up energy to string together glucose molecules into chains of glycogen in our muscles, which are then broken back down into glucose to use as energy later in the day. That extra assembly/disassembly step takes energy” burning up more calories. Calories eaten later in the day result a different metabolic process, which uses fewer calories, leaving more calories to be stored as fat.

There is a saying from The Blue Zones — five populations in the world where people live particularly long and disease-free lives: “Eat breakfast like a king, lunch like a prince, and dinner like a pauper.” Now we know this is not just an “old wives’ tale,” but has scientific validity.

The standard American diet — high in animal fat, refined food and oil — has lots of calories per nutrient (known as high caloric density). If you want to attain and maintain ideal body weight, the most effective approach is to eat a diet with the most nutrients per calorie possible (fruit, vegetables, unprocessed grains). But it’s also important to eat the majority of your calories early in the day.

Greg Feinsinger, M.D. is a retired family physician who has a nonprofit: Prevention and Treatment of Disease Through Nutrition. He gives a free presentation at 7 p.m. the first Monday of the month at the Third Street Center in Carbondale; is available by appointment for free consultations (379-5718); and conducts a shop-with-a-doc session at 10 a.m. the first Saturday of the month at Carbondale City Market.

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