Early Breakfast and Extended Overnight Fasting Linked to Lower Weight

When you eat may be just as important as what you eat when it comes to maintaining a healthy weight, according to new research from the Barcelona Institute for Global Health. A comprehensive study of more than 7,000 adults found that two specific eating habits are associated with lower body mass index over time: extending the overnight fasting period and eating breakfast early in the day. The findings add to growing evidence that meal timing plays a crucial role in weight management and metabolic health.

The research, published in the International Journal of Behavioral Nutrition and Physical Activity, followed participants from the GCAT | Genomes for Life cohort for five years, tracking changes in weight, eating patterns, and lifestyle factors. In 2018, participants between the ages of 40-65 provided detailed information about their meal timing, dietary habits, and health status. When researchers conducted follow-up assessments in 2023, they found clear patterns linking specific eating behaviors to weight outcomes.

"Our results, in line with other recent studies, suggest that extending the overnight fast could help maintain a healthy weight if accompanied by an early dinner and an early breakfast," explains Luciana Pons-Muzzo, who conducted the research while at ISGlobal and is now at IESE Business School. "We think this may be because eating earlier in the day is more in line with circadian rhythms and allows for better calorie burning and appetite regulation, which can help maintain a healthy weight."

The study revealed significant gender differences in eating patterns and their associated outcomes. Women generally had lower BMI values and followed the Mediterranean diet more closely, while also being less likely to consume alcohol. However, they reported poorer mental health and were more often responsible for household supervision. Among men, researchers identified a distinct subgroup that practiced extreme intermittent fasting by skipping breakfast and eating their first meal after 2:00 PM, fasting for approximately 17 hours daily.

Interestingly, this extreme fasting pattern among men was not associated with weight benefits and was linked to concerning lifestyle factors. Men in this group were more likely to smoke, drink alcohol, be less physically active, and have lower education levels and higher unemployment rates. The researchers found no similar pattern among women, suggesting that the relationship between meal timing and health outcomes may vary significantly between genders. The study's authors emphasize that while the results are promising, more research is needed before making definitive dietary recommendations based on meal timing alone.