Metabolism: This role is played by the time of eating

“Eat like a king in the morning, like a nobleman at lunchtime and like a beggar in the evening.” Many people will probably still have these words in their ears when it comes to the three main meals. But whether there is really anything to the proverb is a controversial debate in science.

For a long time, it was questionable whether the time of day had any influence at all. “It used to be assumed that a calorie is a calorie and that it makes no difference when it is consumed,” says Olga Ramich, head of the Molecular Nutritional Medicine research group at the German Institute for Human Nutrition Potsdam-Rehbrücke (DIfE).

Assumption: Time of day does not affect energy metabolism

And indeed, there are studies that confirm this at first glance: just recently, a team from the Scottish University of Aberdeen reported that, at least in terms of energy metabolism, it makes no difference whether you consume the majority of your daily calories in the morning or in the evening.

However, the overweight subjects did notice a benefit of a large breakfast, co-author Alexandra Johnstone said in a statement: “Participants reported that on the days they ate a larger breakfast, they had better control over their appetite and felt more motivated to eat.” felt full for the rest of the day.”

Breakfast: Better satiety throughout the day

For Olga Ramich, this observed feeling of satiety is interesting: “There is no direct regulation of the metabolism through the temporal distribution of calories, but there is a positive effect on behavior.” triggered metabolic reaction.

“For example, my research group conducted studies in which we compared the effects of the same meal in the morning and in the afternoon,” says Ramich. “We found that the blood sugar rises much more after a late meal than in the morning.” The body is also better able to metabolize carbohydrates in the morning.

Differences in blood sugar and insulin levels

This observation fits with a study by the University of Lübeck. In this, 16 normal-weight men received a low-calorie breakfast and a high-calorie dinner in the first phase and vice versa in the second phase. As the research team observed, the rise in blood sugar and insulin levels was significantly reduced after breakfast compared to dinner. The scientists concluded that the human energy turnover is generally higher in the morning than in the evening.

Work like this is particularly interesting for the so-called chrono-nutrition. This field of research examines the connection between the biological clock and food intake, which has often been neglected in the past. But it is precisely this connection that is extremely important, says Ramich from DIfE: “Everything is time-dependent: the circadian clock determines both metabolic processes and our behavior.

Internal clock determines metabolic processes and behavior

A distinction is made between two so-called chronotypes: while larks have energy in the morning and tend to go to bed earlier, owls stay awake longer and find it difficult to get going early in the day. Owls in particular would tend to skip breakfast. According to some studies, they also consume more fast food, coffee and alcohol, as Olga Ramich explains.

Part of this unhealthy behavior is believed to be due to the fact that social rhythm often works against owls’ biological rhythms. “People like that in particular should pay attention to a healthy diet, fixed meal times and breakfast,” emphasizes Ramich, referring to studies that show that skipping the morning meal increases the risk of cardiovascular disease, nutrient deficiencies, obesity and type 2 diabetes elevated. “Owls are often not hungry in the morning, but even they are recommended to get used to eating at least a little something for breakfast.”

Overall, according to nutritionist Ramich, the saying “breakfast like a king” is probably correct. Nevertheless, the total amount of calories for the day should be taken into account when eating a hearty breakfast: “Of course, it is not only important when you eat, but also what you eat and how much you eat. And that should be balanced and healthy, especially for breakfast.”