Biologists from the University of Aberdeen have shown that the timing of the main meal does not affect a person’s metabolism, but a hearty breakfast can contribute to easier weight loss. Results published In Cell Metabolism.
The authors included healthy people who were overweight or obese – 16 men and 14 women. Each participant was randomly assigned to eat the majority of their morning or evening calories for four weeks. The diet was low in calories, with a balance of 30% protein, 35% carbohydrates and 35% fat. After four weeks, each participant took a week off and then returned to the diet, but if the main meal was before morning, now it is evening and vice versa. Thus, each participant was their own control group.
The total daily energy expenditure of the subjects was measured using the dual water labeling method. Energy expenditure and overall weight loss were similar for both groups. Participants lost an average of just over 3kg in each of the four-week periods.
Participants reported that on days when they had a hearty breakfast, their appetite was better controlled and they felt full for the rest of the day. While the circadian rhythm doesn’t affect weight loss, a hearty breakfast can help people lose weight in real life rather than in research settings.