The Exchange

Commentary and Observations from
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Do Meal Times Affect Weight Control?

Do Meal Times Affect Weight Control?

In 2009, researchers at Northwestern University conducted a study on mice and timed feeding, later publishing their research in Obesity. For 6 weeks mice were fed a high-fat diet during a 12-hour dark phase, when they were normally active, or during a 12-hour light phase, when they were normally resting. Feeding was unrestricted during these 12-hour periods and both groups of mice had similar activity levels and calorie consumption. Results indicated that the mice who ate when they should be sleeping had an average 48% gain to their body weight, compared to a 20% increase in the mice who ate the high-fat diet during their normal waking hours.

Since that time, additional studies have looked at time of eating and weight control in humans. Counseling obese patients over the years, we talked about total calories consumed in a 24-hour period, though there was never a discussion about time of eating. Now there is new evidence that the timing of calorie consumption might matter. Eating the majority of our calories in the morning rather than at night may lead to improved body weight, hormone regulation, blood sugar and cholesterol levels as well as healthier sleep patterns. In one study, big breakfast eaters had more than twice the amount of weight loss compared to the big dinner eaters. The breakfast eaters also had improvements in triglyceride and cholesterol levels, and better insulin levels throughout the day. Additionally, the research subjects assigned to the bigger breakfast had fewer dropouts, suggesting that eating your biggest meal in the morning may be a more sustainable habit.

Additional analyses and studies support the time of day eating and weight control theory. In another study, participants were given an identical meal one week apart with the only difference being the timing of the meal (one in the morning and one in the evening). Again, the morning eaters came out ahead with improvements in blood glucose levels and a slight boost in metabolic rate. Other research reveals that sleep patterns are better among study subjects who eat the majority of their calories in the mornings rather than in the evening.

This may be something to consider when counseling patients on behaviors likely contributing to obesity.

  • Contie V. Timing of meal may affect weight gain. Accessed August 5, 2019.
  • Jakubowicz D, Barnea M, Wainstein J, Froy O. High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women. Accessed August 5, 2019.
  • Bo S, Fadda M, Castiglione A, et al. Is the timing of caloric intake associated with variation in diet-induced thermogenesis and in the metabolic pattern? A randomized cross-over Accessed August 5, 2019.
  • Raynor HA, Li F, Cardoso C. Daily pattern of energy distribution and weight loss. Accessed August 5, 2019.

Filed under: Preventive Medicine, Public Health

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