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Meal timing affects glucose tolerance and overall health
Last reviewed: 02.07.2025
Although many have always claimed that a light and early dinner is healthier, a study conducted by the Open Education University of Catalonia (UOC) and Columbia University has provided scientific evidence to support this claim.
According to a study published in the journal Nutrition & Diabetes, consuming more than 45% of your daily calories after 5 p.m. is associated with elevated blood glucose levels, which can be harmful to health, regardless of weight or body fat content.
Main results of the study
The study was conducted at Columbia University Irving Medical Center in New York City and led by Dr Diana Diaz Rizzolo, a research fellow in the UOC Faculty of Health Sciences.
"Maintaining high glucose levels over long periods of time can lead to an increased risk of developing type 2 diabetes, increased cardiovascular risks due to blood vessel damage, and chronic inflammation that worsens cardiometabolic damage," Diaz Rizzolo said.
Previously, it was believed that the main result of eating late was weight gain. This was associated with the fact that in the evening people more often choose high-calorie and ultra-processed foods, since the hormones that regulate hunger and satiety change when eating at night.
However, the importance of this study is that it demonstrates that meal timing itself can negatively impact glucose metabolism, independent of calorie intake and body weight.
Late versus early eaters
The study involved 26 people aged 50 to 70 who were overweight or obese and had prediabetes or type 2 diabetes. Glucose tolerance levels were compared between the two groups:
- Early eaters who consumed most of their calories before evening.
- Late eaters who consumed 45% or more of their daily calories after 5:00 p.m.
Both groups consumed the same amount of calories and the same food, but at different times of day. Participants used a mobile app to record their meals in real time.
Key findings:
- Late eaters had worse glucose tolerance, regardless of their weight and diet composition.
- They also consumed more carbohydrates and fat in the evening.
Why does this happen?
Diaz Rizzolo explained that the body's ability to metabolize glucose is limited at night. This is due to:
- decreased insulin secretion;
- decreased sensitivity of cells to insulin due to circadian rhythms, which are regulated by a biological clock synchronized with the day-night cycle.
The Importance of Proper Meal Timing
The study highlighted the importance of meal timing for health.
"Until now, personal nutrition decisions have been based on two main questions: how much we eat and what we choose. This study introduces a new factor in cardiometabolic health: when we eat," Diaz Rizzolo said.
Recommendations:
- Main meals should be planned during the daytime.
- The greatest caloric intake should be at breakfast and lunch, not at tea and dinner.
- You should avoid eating ultra-processed foods, fast foods and foods rich in carbohydrates, especially in the evening.
Conclusion
The study demonstrates that late dinners may negatively affect glucose metabolism and increase the risk of cardiovascular disease. Early and balanced meals become an important component of preventing metabolic disorders and maintaining health.