Science has a clear answer to one of the most repeated questions at the family table: what is the best time to have dinner? It's not a universal magic hour, but experts agree that leaving at least three hours between dinner and bedtime is key for your body to process food properly. This conclusion comes from chrononutrition, an emerging field that studies how our internal biological clock (circadian rhythm) influences metabolism.
An article by BBC Future health correspondent Melissa Hogenboom, published on August 19, 2026, analyzes multiple studies showing that your body doesn't metabolize a meal at 1 PM the same way it does at 10 PM. “From a biological standpoint, we are not the same person in the morning and at night,” says Frank Scheer, professor of medicine and neuroscientist at Brigham and Women's Hospital in Boston, in statements to the BBC.
The Circadian Mismatch: What Happens If You Eat Late
Eating when your biological clock signals it's time to sleep creates a “circadian misalignment.” A 2022 study with more than 800 adults showed that consuming a glucose drink (similar to a dinner) one hour before sleep results in higher blood sugar levels and lower insulin production than if taken four hours earlier. The culprit is melatonin, the sleep hormone: when its levels rise, the body reduces its ability to regulate glucose.
The effect is even stronger in people carrying a common variant of the MTNR1B gene, linked to a higher risk of type 2 diabetes. “If you eat when melatonin is elevated, your glucose control will be affected,” explains Scheer.
Cardiovascular Risk: Dining After 9 PM Raises Stroke Risk by 28%
A study published in Nature Communications by the Barcelona Institute for Global Health, with over 100,000 participants, found that eating dinner after 9 PM is associated with a 28% higher risk of cerebrovascular diseases (like stroke) compared to eating before 8 PM. The risk is especially notable in women.
Additionally, a longer overnight fast – achieved by eating dinner earlier rather than delaying breakfast – is linked to better heart health. Dietitian Victoria Taylor from the British Heart Foundation notes that “concentrating your intake during the day and avoiding late-night eating could benefit health,” though she cautions that evidence is not yet conclusive.
Why an Early Lunch Helps with Weight Loss
Researcher Marta Garaulet from the University of Murcia (Spain) followed 420 adults for 20 weeks and found that those who ate lunch earlier lost more weight and lost it faster than those who ate later. A controlled trial with 32 healthy women showed that late lunch led to worse glycemic control and lower carbohydrate burning.
Another international study with nearly 1,200 adults (in which Scheer participated) revealed that eating later is linked to a higher body mass index (BMI) in people genetically predisposed to obesity, while eating earlier reduces that risk.
Hunger and Fat Storage
Eating late alters appetite hormones: it produces less leptin (the satiety hormone) and more ghrelin (the hunger hormone), making you feel hungrier the next day. Additionally, the body tends to store fat in cells rather than break it down, making it harder to maintain a healthy weight.
Practical Tips from Experts
- Eat dinner at least 3 hours before bed. There's no universal hour, but that interval is the most recommended.
- Make lunch your largest meal and opt for a light dinner rich in protein.
- Include tryptophan-rich foods in dinner (nuts, seeds, chicken, salmon) to improve sleep quality.
- Respect your chronotype: “morning larks” tolerate early meals better; “night owls” should try to gradually advance dinner time.
- Avoid extreme fasting: reducing your eating window too much can backfire. The key is consistency.
In short, science hasn't yet defined an exact dinner hour, but all studies agree that eating earlier and leaving a longer overnight fast benefits weight, glucose, and heart health. As the Spanish saying goes: “Eat breakfast like a king, lunch like a prince, and dinner like a pauper.” Your biological clock will thank you.
Sources: BBC News Mundo, Meteored, La Razón, Súmédico.