Take It In: Control weight with meal timing, exercise

Mar 25, 2020 by Carol Bareuther

Take It In: by Carol Bareuther

Eat breakfast like a king, lunch like a prince and dinner like a pauper. Add moderate exercise to this age-old wisdom and you’ve got the prescription for weight loss or weight maintenance without necessarily following a special diet. These are the results and take-home recommendations of two recent studies.

In the first, Australian researchers writing in the January 2020 issue of Exercises and Sports Sciences Review looked at the effect of what they termed time-restricted eating, or TRE. This means eating over 8 to 10 hours a day so that the other 14 to 16 hours of the day you’re, in effect, fasting. What led the researchers to look at the idea of TRE was the realization that our ancestors’ biological clock, including when they ate, was set by natural factors like sunrise and sunset. The rise and fall of various hormones in our bodies operates much the same way today. 

However, our lifestyle is very different. We can keep lights on any hour of the day, and we have round-the-clock access to food. Add in not getting enough sleep or exercise to today’s lifestyle, and these are all key culprits causing the current obesity epidemic. 

When the Australian researchers reviewed previous studies, they found that a limited eating “window” of less than 10 hours a day helped in weight control. Specifically, in one study, overweight subjects lost 3% of their body weight by eating 20% fewer calories by eating over 10 hours rather than 14. An example of 10 hours is having breakfast at 8 a.m., dinner just before 6 p.m. and lunch somewhere in the middle. 

Researchers noted that the TRE success could be because what we eat often corresponds to time of day. In other words, perhaps these subjects weren’t having that big bowl of ice cream, bag of chips, or box of cookies while watching TV at night because they didn’t eat after a certain time. They did note that eating earlier in the day proved more beneficial than a 10-hour span running later, such as noon to 10 p.m. 

A bonus in this research is that subjects maintained their weight loss for a year, yet they didn’t change what or how much they ate. This makes the idea of TRE a practical, even painless, method of long-term weight control. 

The second study found that adding exercise wasn’t only a way to burn calories, but to help curb appetite and make it easier to stick to a calorie-reduced diet. Specifically, U.S. researchers writing in the March 2020 issue of the Journal of Health Psychology found that when study participants engaged in an hour of moderate physical activity, the odds of overeating or “going off their diet” dropped from 12% to 5%. This they ascribed to the appetite suppressing effect of exercise. 

Interestingly, the researchers noted that moderate exercise was better at decreasing appetite and overeating than vigorous activity. That means, a brisk walk, game of doubles tennis or bike ride at less than 10 mph might be better exercise for appetite control than swift running, swimming laps or aerobic dancing.

Taken together, these two studies suggest that limiting eating to 10 hours and adding moderate exercise to your day can be potent, yet rather painless, ways to reach or maintain a healthy weight. Of course, while neither study directly addressed diet, eating nutrient-rich foods is always a plus. This means plenty of fruits and vegetables, whole grains, low-fat dairy foods, and lean proteins from meat, poultry, fish, nuts, seeds and beans. 

Carol Bareuther is a registered dietitian and freelance health and nutrition writer. Comments are welcome below.