Winter time is already here – and that means that even before many of us leave work, it’s already dark outside. The pace of life in winter often feels heavier, the days are shorter, the evening arrives early, and eating hours change as well. But a small change in meal timing can ease the body and mind during this season.
Our body operates according to circadian rhythms – 24-hour “biological clocks” that regulate sleep, metabolism, digestion and hormone secretion. These rhythms are naturally synchronized with light and darkness, which is why when the light disappears earlier – metabolism also begins to slow down.
The connection between daylight and metabolic activity explains why a developing research field called chrononutrition points to the fact that the timing of when we eat can be almost as important as what we eat. The field examines how meal timing affects our biological clock, and our mood, metabolism and health during seasons of limited light.
Various studies show that not only what we eat matters – but also when.
For example, in a study published in 2019 that lasted a year, experts from Columbia University studied 112 women whose average age was 33. The results showed that eating after 18:00 was linked to poorer heart health: Women who consumed a higher proportion of their daily calories after this hour suffered from a higher average blood pressure. They were also overweight and had higher blood sugar levels – two severe risk factors for heart disease.
Another study found that healthy adults who ate dinner at 22:00 experienced a 20% rise in blood sugar levels and burned about 10% less fat compared to those who ate the same meal at 18:00 – even though both groups ate the same menu and went to sleep at the same time.
A large review of 29 studies reinforced the results: An earlier eating window, fewer meals per day and eating most of the calories in the morning and afternoon are linked to greater weight loss and improvements in metabolic markers such as blood pressure, sugar levels and cholesterol.
In contrast, consistent eating at late hours – especially close to bedtime – is associated with increased risk of obesity and metabolic diseases, such as type 2 diabetes.
Why does an earlier meal help?
When you eat relatively early, dinner aligns better with the body’s natural metabolic rhythm. When the meal takes place long before the “rest” phase, metabolism works more efficiently.
Many researchers in the field of biological clocks believe that adjusting meal times to day-night cycles may be a cheap and efficient tool for improving metabolic health – especially combined with physical activity and a balanced diet.
In addition, in winter we get less sunlight, which lowers serotonin levels, which may affect mood and even lead to seasonal depression (SAD). At the same time, long evenings at home increase snacking and delay dinner to late hours.
But digestion, sleep-related and digestion-related hormones, and the amount of energy the body burns – all operate according to an internal clock. Eating too close to bedtime causes digestion and rest processes to occur simultaneously – a situation that can harm sleep quality and metabolism.
If sitting down to dinner between 17:00–19:00 is impossible for you, eating before 20:00 is still preferable to a late dinner and can help prevent blood sugar spikes that may occur when eating close to bedtime. A dinner time between 18:00 and 20:00 is a more flexible option for those who need to balance busy schedules, without risking eating too late in the evening.