Study finds two key habits to lower body fat without dieting

Sometimes it’s not just what you eat, but when you eat it. And there are two habits linked to timing that could help lower body fat levels. A study by Luciana Pons‑Muzzo of the Barcelona Institute for Global Health has revealed just why timing matters when eating. So, what did she find? (Picture: Getty)

What was the study?

Pons‑Muzzo conducted a five-year project which looked at more than 7,000 volunteers who were middle aged. The researchers asked participants in 2018 to answer questionnaires about their weight, height, eating habits, meal times and their other lifestyle habits, as well as their socioeconomic status. Then, five years later in 2023, more than 3,000 of the participants made a follow up visit, where the data was taken again (Picture: Getty)

What did they find?

The aim of the study was to investigate the science of meal timings, and the effects it has on metabolism. The researchers discovered that there were two specific habits that were associated with a lower body mass index (BMI) in the long term. They found that those who ate breakfast before 8.30am but also left around 12 hours between dinner and breakfast had lower BMI. So they concluded the two habits were: 
• Keeping a longer overnight fast 
• Eating breakfast earlier

(Picture: Getty)

What does this mean?

Explaining her study, Pons-Muzzo said: ‘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. 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. However, it is too soon to draw definitive conclusions, so recommendations will have to wait for more robust evidence’(Picture: Getty)

Why do some forms of intermittent fasting work?

We have circadian rhythms which tune our organs to burn and store energy at specific times. Morning light boosts insulin sensitivity and drives metabolism, while late‑night eating leads to hormonal signals that favour fat storage. This is also backed up with data, with one study showing that adults on an eight‑hour early eating window lost as much weight as peers on standard calorie restriction – but without counting calories. Other research shows that time‑restricted plans typically take off 7–11 lbs over ten weeks, largely because shortening the eating window curbs unplanned snacking (Picture: Getty)

How does having an earlier breakfast help you lose weight?

When a person has an earlier breakfast, they tend to have an earlier dinner. This means, when coupled with intermittent fasting, that there is a lengthening in the overnight fast. It also allows glucose and insulin to settle before sleep and aligns digestion with daylight activity. However, it is important to eat breakfast, and food in general, as the researchers advise against 24 hour fasts. Senior co-author Camille Lassale said: ‘This practice has no effect on body weight’(Picture: Getty)

So, what times should you eat?

The times you should eat depends on how long you want to intermittent fast for. For a 13-hour stretch you could have dinner at 6pm and breakfast the following day at 7am, which will be long enough to trigger metabolic benefits yet short enough that you can still grab dinner with friends after work. However, it is important to note this is not the only way to lose weight, and the review found that weight loss from timing strategies averaged only 3–4% of starting weight. It is important to consult a clinician or doctor before starting any weight-loss regime. The study is published in the International Journal of Behavioral Nutrition and Physical Activity (Picture: Getty)