Two eating habits that will permanently free you from excess weight
An early breakfast and an early dinner with a long overnight fasting period — this combination turned out to be associated with lower body weight in thousands of people over five years of observation. Researchers from the Barcelona Institute for Global Health (ISGlobal) analyzed data from more than 7,000 people and concluded: it’s not just about what we eat, but also when we eat it.
How Meal Timing Affects Body Weight
Scientists studied eating habits and weight data of 7,074 people aged 40 to 65. Participants were observed over five years, with researchers recording breakfast and dinner times, meal frequency, and the duration of the overnight fasting period.
The results showed a consistent pattern: people who ate breakfast earlier and had a longer overnight fast had a lower body mass index (BMI) after five years. Conversely, late breakfasts and frequent snacking throughout the day were associated with higher BMI.
It’s important to note that BMI is not a perfect metric. It doesn’t account for the ratio of muscle to fat mass and is frequently criticized by specialists. Nevertheless, in large population studies, it remains one of the standard benchmarks.
How Circadian Rhythms Affect Weight and Metabolism
Why might meal timing affect weight? Researchers believe the key lies in circadian rhythms — the body’s internal biological clocks that regulate numerous processes throughout the day.
“We think this is related to the fact that eating earlier in the day is better synchronized with circadian rhythms and allows the body to burn calories and regulate appetite more efficiently,” explains epidemiologist Luciana Pons-Muzzo from ISGlobal.
Simply put, the body is designed to actively process food during the first half of the day. When we eat a late dinner, have a late breakfast, or eat before bed, we are essentially “feeding” the body at the wrong time — like fueling a car that’s parked in the garage. Early eating helps the body use calories when it’s ready for them, rather than storing them as reserves.
Additionally, scientists suggest that a long overnight fasting period may better regulate insulin production and fat storage management, although further research is needed for definitive conclusions.
Why Skipping Breakfast Doesn’t Help with Weight Loss
One of the most intriguing findings concerns men who practiced a form of intermittent fasting by simply skipping breakfast. Through cluster analysis (a method of grouping participants by similar habits), scientists identified a distinct group of men who didn’t eat their first meal until after 2:00 PM, with an average overnight fast of 17 hours.
Skipping breakfast for fasting showed no effect on weight loss
“We observed that in the subgroup of men practicing intermittent fasting by skipping breakfast, this strategy had no impact on body weight,” says epidemiologist Camille Lassale from ISGlobal.
She also notes that other interventional studies on people with obesity have shown that skipping breakfast is no more effective in the long term than simply reducing calorie intake. In other words, fasting alone offers no advantage if it shifts eating to the second half of the day.
What matters is the combination: early breakfast + early dinner + a long overnight pause.
What Is Chrononutrition and How Does It Affect Weight
This research belongs to a relatively young field — chrononutrition. This is an area of science that studies not only the composition of the diet but also meal timing, frequency, and how all of this aligns with the body’s internal clocks.
“Our research is based on the understanding that atypical eating patterns can conflict with the circadian system — a set of internal clocks that regulate day and night cycles and the accompanying physiological processes,” explains epidemiologist Anna Palomar-Cros from ISGlobal.
The associations were particularly pronounced in premenopausal women. Researchers cannot yet explain precisely why this group showed the strongest connection, but hormonal cycles and their interaction with circadian rhythms are one of the likely directions for future research.
Chrononutrition studies the connection between meal timing and health
It’s important to emphasize that this study is observational and does not prove a direct cause-and-effect relationship. Scientists used several statistical methods and accounted for variables such as age and sleep quality, but only clinical trials with clear instructions for participants can ultimately confirm the mechanism.
Which Eating Habits Help Reduce Weight
If we summarize the study’s results, several simple recommendations emerge:
- Eat breakfast earlier rather than skipping the morning meal
- Try to have dinner earlier to extend the overnight fasting period
- Don’t rely on skipping breakfast as a weight loss strategy — according to this study, it doesn’t work
Of course, this is not a magic formula. Weight depends on many factors: total caloric intake, physical activity, genetics, sleep quality, and stress. But shifting meals to earlier times is one of the simplest changes you can try without any costs or risks.
Of course, this is not a magic formula. Weight depends on many factors: total caloric intake, physical activity, genetics, sleep quality, and stress. But shifting meals to earlier times is one of the simplest changes you can try without any costs or risks. Having dinner 3 hours before bed is another useful and simple habit, if you have the willpower.
The study was published in the peer-reviewed journal International Journal of Behavioral Nutrition and Physical Activity. Future research in this field plans to cover more diverse groups of people over longer periods and conduct clinical trials with specific meal timing instructions. For now, science is increasingly confident: for a healthy weight, it’s not just about what’s on your plate, but also when you sit down to eat.
