We are learning, day after day, how important it is not only to respect the rhythm of meals but also to pay attention to the hours in which we consume food. It is the era of chrononutrition, with dietary approaches that increasingly take into account the “meal timing”, the time in which a meal is consumed. This is because the important role of circadian rhythms in the regulation of numerous physiological processes, including the hunger-satiety cycle, is now clear. Now an Italian research is trying to take stock of the situation, starting from the chronobiology of different people and their chronotype.
There are those who are larks, wake up early in the morning, and those who are owls and stand up for a long time. In general, the former seem to be better suited to the table and in lifestyles than the latter. But will it be like this? A confirmation, albeit indirect, comes from an Italian research coordinated by Sofia Lotti with her research group of the University of Florence, presented at the National Congress of the SINU Italian Society of Human Nutrition. Here’s what the study says.
In-depth analysis on the organism
The survey investigated the role of the chronotype on body composition, dietary habits and cardiometabolic risk parameters in overweight and obese subjects. Participants were recruited at the Clinical Nutrition Unit of the Careggi University Hospital in Florence, from March to April 2023. During the visit, each participant underwent an assessment of body composition and a blood sample.
The individual chronotype was defined using the validated questionnaire most used for this purpose in the literature, the Morningness-Eveningness Questionnaire (MEQ). Furthermore, information on eating habits was collected with a food frequency questionnaire and by filling in a 3-day food diary. The total sample consisted of 51 overweight/obese subjects (BMI≥25 kg/m2), of which 71% women and 29% men, with a mean age of 50.3 ± 13.5 years and a mean BMI of 29.4 ± 4.3 kg/m2. Based on the MEQ total score, 26% of participants had an evening chronotype, while 74% had a morning chronotype.
From the analysis of eating habits it emerged that subjects with evening chronotype consumed significantly more daily calories than early risers (+255 kcal/day) and interestingly, the calorie distribution of meals changed according to circadian preference, with late risers consuming significantly more calories at lunch (+88 kcal) and dinner (+166 kcal) compared to matins. The evening subjects also reported to follow a diet significantly richer in carbohydrates (+40 g/day) and fats (+13 g/day), due to a higher consumption of sugary drinks, fast foods and sweets.
By analyzing the timing of meal consumption, it emerged that subjects with an evening chronotype tended to consume all meals later than in the morning, reaching statistical significance for breakfast and dinner. Despite these differences in dietary regimen, the body composition of the morning and evening subjects was similar. Finally, here’s some data on blood tests: the serotini showed significantly lower values of folic acid and vitamin B12.
How to read this data
What can be said? What is certain is that according to the study there are no significant differences in body composition between owls and larks, it appears confirmed that the former are at greater risk of eating habits. Evening subjects associate with worst eating habits both in terms of dietary quality and in terms of meal timing, assuming more total daily calories, fat and carbohydrates, and consuming meals at late times.
Additionally, evening subjects reported lower blood levels of folic acid and vitamin B12. These worse eating behaviors may have negative implications for the health of evening subjects. And new research will help clarify these aspects even better.