Does Timing of Calories Matter?

overhead view of person eating breakfast

If you’re trying to lose weight or prevent weight gain, does it matter what time of day you eat the majority of your calories? Past and present research suggests that it does.

Should Breakfast Be Your Heaviest Meal?

For many of us, breakfast and lunch, if eaten at all, are the lightest meals of the day. But it wasn’t always that way. Before we moved to a more sedentary lifestyle, breakfasts were designed to provide substantial fuel and nutrition for a more physically active day.

There is a famous line by American nutritionist Adelle Davis (1904 – 1974): “Eat breakfast like a king, lunch like a prince, and dinner like a pauper.” In other words, make dinner your lightest meal instead of your heaviest.

And there is a lot of scientific evidence to back this up. Studies have shown that people who eat the majority of their calories earlier in the day tend to lose more weight—and do so faster--than those who save their calories for the evening or night. This may be because eating more food earlier gives you time to burn those calories as you naturally expend energy throughout the day, but other studies have shown changes in levels of the appetite hormones, leptin and ghrelin, that also play a role.

Meal Timing Found to Make a Difference

In one Mediterranean study that looked at over 400 participants who followed a 20-week weight-loss intervention, researchers looked at when subjects ate lunch.

They found that 51% of participants were “early eaters,” eating lunch before 3:00 p.m.; and 49% were “late eaters,” eating lunch (the main meal of the day in this Mediterranean population) after 3 p.m.

The researchers found that the group of late lunch eaters loss less weight, and took longer to lose weight, during the 20 weeks of weight-loss treatment than did those who ate lunch (and, thus, the majority of their daily calories) earlier.

In another study, scientists assessed several metabolism-related variables in 32 women who were studied under two lunch-eating conditions: one group ate lunch at 1:00 p.m. while the other group ate lunch at 4:30 p.m. The study authors found that eating late resulted in “decreased resting-energy expenditure,” which may be thought of as a lower basal metabolic rate (i.e., not able to burn as many calories at rest).

Interestingly, these study authors also found that eating late was associated with decreased glucose tolerance (a condition that in the long run leads to pre-diabetes and diabetes). The authors concluded that the results may show that meal timing matters when it comes to “metabolic health.”

It is important to note that these studies were performed in a Mediterranean population, where lunch is the main meal of the day and thus constitutes the majority of daily calories. This would thus be similar to eating a typical American dinner, which is eaten later in the day and also is usually the most calorie-laden meal of the day.

Looks as though it may be time to change that!


Garaulet M, Gomez-Abellan P, Alburquerque-Bejar JJ, et al. Timing of food intake predicts weight loss effectiveness. International Journal of Obesity 2013;37:604-611.

Garaulet M, Gomez-Abelian P. Timing of food intake and obesity: a novel association. Physiol Behav 2014;134:44-50.

Bandin C et al. Meal timing affects glucose tolerance, substrate oxidation and circadian-related variables: A randomized, crossover trial. Int J Obes 2015.

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