Eating earlier linked to maintaining long-term weight loss

A study led by researchers from Complutense University of Madrid suggests that consuming meals earlier in the day may reduce weight gain typically associated with a high genetic predisposition for obesity.

The timing of meals has previously been studied for its effects on metabolism, energy use, and circadian rhythm alignment. Zeitgeber, which includes regular occurrences regulating the body's circadian rhythms, can synchronize metabolic tissues such as the liver, pancreas, and fat tissue.

Changes to meal times can affect zeitgeber, altering molecular timing of circadian clock cues and consequently impacting metabolic function rhythms.

Peripheral oscillators in metabolic organs that are sensitive to food timing may become out of sync with the central clock regulated by environmental light. This internal misalignment could contribute to negative cardiometabolic traits and obesity.

In the study, "Early meal timing moderates high polygenic risk of obesity," published in Obesity, researchers conducted linear regression analyses to test whether meal timing interacts with a genome-wide polygenic score affecting BMI and long-term weight loss maintenance.

The research involved 1,195 overweight or obese adults (average age 41 years, 80.8% female) from six Spanish weight-loss clinics participating in the Obesity Nutrigenetics Timing Mediterranean (ONTIME) study. They combined a 16-week behavioral weight loss treatment with follow-up assessments approximately 12 years later.

Investigators calculated BMI polygenic risk scores based on 900,492 single-nucleotide polymorphisms and assessed meal timing using the midpoint of intake—calculated as the time halfway between participants' first and last meals over weekdays and weekends. Linear regression models were adjusted for age, sex, clinic site, and ancestry components.

For each hour later in the day of midpoint meals, there was a 0.952 kg/m² increase in baseline BMI and a 2.2% rise in body weight at the 12-year mark (±3 years) post-treatment. In the highest polygenic risk tertile, BMI rose by about 2.21 kg/m² for every hour meal time was delayed. No such association appeared in lower-risk groups.

The authors suggest that meal timing is linked to weight-loss maintenance and mitigates genetic risk factors, proposing that early eating could be part of personalized obesity intervention strategies.