It has long been thought that calories are calories, but when it comes to losing weight, it doesn’t matter what time of the day they are consumed.
However, recent research has challenged this notion, suggesting that the timing of calorie intake and how the calories are distributed throughout the day can influence weight loss effectiveness. .
These findings suggest that meal timing that is out of sync with the body’s circadian rhythm (the 24-hour cycle that governs calorie burning, digestion, nutrient metabolism, and other bodily processes) is in a way that exceeds the number of calories consumed each day. suggesting that it may contribute to weight gain. .
Now, two rigorously controlled trials, both published this month in Cell Metabolism. It supports the theory that proper timing and distribution of daily calories can benefit weight loss.
Here’s what you need to know about the latest research and how the findings apply.
A large breakfast can reduce hunger
A study conducted by researchers at the University of Aberdeen in the UK investigated whether eating more breakfast and less dinner helped you lose weight.
Thirty overweight or obese participants were assigned to one of two diets. They consumed most of their daily calories at breakfast (45%), less at lunch (35%), and least at dinner (20%). In the other group, at breakfast he ate 20% of his daily calories, 35% at lunch, and 45% at dinner.
After 4 weeks, the groups were switched to continue on the opposite diet.
Calories (1,700 per day), meal composition (protein, carbohydrate, fat, etc.), and meal frequency were consistent for both diets. The only difference was the calorie load at breakfast or dinner.
Researchers provided all food and drink. Participants’ daily energy expenditure, resting metabolism, appetite, and weight loss were measured throughout the study.
Both diets produced similar weight loss after 4 weeks (7 pounds). There was also no difference in daily calorie burn or resting metabolism between the two groups.
Calorie distribution affected appetite control. Eating more breakfast made me feel significantly less hungry and more full during the day compared to eating more dinner.
These findings contradict previous studies that suggested eating a large breakfast and a light dinner increased calorie expenditure.
Instead, they suggest that eating the largest meal of the day in the morning reduces appetite and reduces caloric intake, which may contribute to weight loss over time. doing.
Eating late increases hunger and reduces calorie burn
Previous studies have shown that eating late increases the risk of obesity and reduces weight loss success. These results could not be explained by differences in calorie intake or physical activity.
In a second study, researchers at Brigham and Women’s Hospital in Boston attempted to determine how delaying eating might affect the risk of obesity.
In a laboratory experiment, 16 healthy overweight or obese adults completed two 6-day dietary protocols. An early eating protocol with meals at 8:00 am, noon, and 4:00 pm, and a late eating protocol that schedules the exact same meal at 4:00 noon.pm and 8 pm
Physical activity, posture, sleep, and light exposure were strictly controlled.
Researchers measured perceived hunger and appetite, levels of appetite-regulating hormones, and calorie burn. They also looked at gene activity in adipose tissue.
Late eaters were twice as likely to report hunger during the day than fast eaters. Levels of leptin, a hormone that signals satiety, decreased with the slow-eating protocol compared to the fast-eating protocol.
When participants ate later, they burned an average of 60 fewer calories per day than when they ate earlier. Among slow eaters, adipose tissue gene activity showed changes indicative of increased fat storage and decreased fat burning.
The researchers noted that the increased appetite observed with slow eating could be even more pronounced in a real-world setting where people can eat as often as they like.
limitation, impact
Both studies were small and short-lived. For example, it is not known whether the observed effects of slow eating persist over time.
And whether the decreased appetite associated with eating more breakfast leads to lower caloric intake, or whether this effect depends on the timing of dinner, remains to be demonstrated.
Still, these findings are intriguing and might make you pause to skip breakfast or eat dinner late.
If you are on a timed meal, you may be urged to change your meal window from evening to morning or afternoon.
Toronto-based private practice dietician Leslie Beck is Medcan’s Director of Food and Nutrition. follow her on her twitter @LeslieBeckRD
