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Shifting your meal intake to the morning helps curb your genetic predisposition to obesity
Last reviewed: 09.08.2025
">A team of scientists from the University of California, San Diego, led by Professor Daniela Anderson, published in Obesity the results of a three-year study showing that shifting the main caloric intake of the diet to earlier hours of the day can significantly mitigate the high polygenic risk of obesity.
Design and participants
The study included 1,102 overweight or obese adults (BMI 27–40 kg/m²) who completed a weight loss program. After completing the active phase, the participants kept a food diary and monitored their meal times. Based on DNA analysis, each participant was assigned a polygenic risk score (PGS), an indicator combining more than 500 single-nucleotide polymorphisms associated with BMI and body fat.
The cohort was divided into two groups based on the median PGS: “low risk” and “high risk.” Then, for three years after the diet, weight loss maintenance was recorded and the midpoint was calculated — the average time between the first and last meal of the day.
Main findings
Maintaining Weight Loss
In the low PGS group, there was no significant difference in outcomes between "early" (midpoint before 3:00 PM) and "late eaters."
In the high PGS group, early eaters retained an average of 22% of the weight they lost, while late eaters retained only 16% (30% difference, p < 0.01).
The influence of every hour
Regardless of PGS, each hour delay in midpoint increased the risk of regaining lost weight by 7% after three years (HR = 1.07; 95% CI 1.03–1.11; p < 0.001).
Metabolic markers
Among the "late eaters" with high PGS, higher HOMA-IR (an index of insulin resistance) and postprandial hyperglycemia were observed, whereas "early eaters" demonstrated better glycemic control.
Mechanisms of action
The authors explain the effect by synchronizing nutrition with circadian rhythms:
- Early calories enter active phase metabolism, when enzymes for utilizing glucose and lipids work more efficiently.
- Late meals coincide with the waning biological day, which leads to an imbalance in insulin and ghrelin secretion and promotes lipogenesis.
Practical recommendations
- Plan your main meals (breakfast and lunch) before 3:00 p.m., especially if you have a family history of obesity.
- Control your midpoint: aim for the average time between your first and last meal to be 2:00–3:00 PM
- Don't change the calorie content: the effect is achieved through time, not through reducing energy intake.
“Our data highlight that for people at high genetic risk for obesity, shifting most of their caloric intake to the first half of the day is a simple and effective way to improve the chances of long-term weight maintenance,” comments Dr Anderson.
Prospects
The researchers are planning randomized controlled trials to confirm the effectiveness of chrononutrition recommendations and to clarify optimal feeding intervals for different genetic profiles. This will allow personalized dietary strategies and achieve better results in the fight against obesity.