Nutritional Pearls: When Should You Eat Your Main Meal?
Suzanne is a 33-year-old overweight woman who has recently begun working to maintain a reduced-calorie diet. At her most recent checkup, she asks if the number of meals she eats each day, or limiting food after a specific time of day, could help her to lose more weight.
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Answer: If your patients are working on their weight with a reduced-calorie diet and it fits into their lifestyle, it might be worth trying to have their main meal at lunch, then have a lighter dinner.
Many of my patients are still very concerned about when and how often they should eat. "Should I not eat after a certain time?" they want to know. "Will eating 5 or 6 times a day help me lose weight?" It's fair to say that there's not a lot of good research to answer either question: A 2011 overview of the existing research concluded that eating more frequently might help with glucose spikes, but the overall research into eating more often was contradictory. For years now, my standard answer for the question of how late one should be eating has been that if you're having a late-night snack, there's a good chance you're eating additional calories you may not need.
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Other research has been more interesting. A study published in 2014 showed that for women who were working on losing weight, consuming half their daily calories at breakfast rather than at dinner meant they lost more weight than those who ate half their daily calories at dinner.1
Today's article builds upon that earlier work: 69 healthy but clinically overweight women were assigned reduced-calorie diets designed for them to lose between 0.5 and 1 kg per week for the 12-week duration of the study. They were encouraged to increase their level of physical activity slowly up to 60 minutes per day of brisk walking 5 days per week, met regularly with dietitians and weight-loss counselors, and kept food diaries for 4 days of every week.2
The women were randomly assigned to 1 of 2 groups: a lunch meal group, in which they consumed 50% of their daily calories at lunch, 20% at dinner, and the rest as breakfast and snacks, or a dinner meal group, in which 50% of their calories were consumed at the dinner meal and 20% at lunch time.
After the 12 weeks of the study, the results were quite similar to the previous study on breakfast. Those who ate their main meal at dinner time lost an average of 4.3 kg (about 9.5 lb), while those who at their main meal at lunch lost about 5.7 kg (about 12.7 lb). Those who ate half the day's calories at lunch time lost a third more weight than those who ate the larger dinner.
It's interesting to note that the lunch meal group improved their insulin resistance more than those in the dinner meal group. Otherwise, the difference in results between the 2 groups were not particularly significant: their waist circumference, total cholesterol, and high-density lipoprotein cholesterol all improved about as much as one would expect from the overall weight loss.
What’s the “Take-Home”?
The authors caution that this study was performed in women who were already motivated to join a weight-loss program, and those women received intensive counseling and daily telephone contact from dietitians. Further, this does not look at how well the women maintained their reduced weight and if that was affected by whether they continued to eat their main meal at the time assigned. If your patients are working on their weight with a reduced-calorie diet, however, and it fits into their lifestyle, it might be worth trying to have their main meal at lunch, with a lighter dinner.
Jakubowicz D, Barnea M, Wainstein J, Froy O. High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women. Obesity. 2013;21(12):2504-2512.
Madjd A, Taylor MA, Delavari A, Malekzadeh R, Macdonald IA, Farshchi HR. Beneficial effect of high energy intake at lunch rather than dinner on weight loss in healthy obese women in a weight-loss program: a randomized clinical trial. Am J Clin Nutr. 2016;104(4):982-989.