Late lunch linked to less weight loss in Spanish population

Recent animal studies have linked energy regulation to the circadian clock, which suggests that the timing of meals may have an important role in weight regulation.

This human study investigated if the timing of meals affected weight loss. Study participants included 420 Spanish adults who were taking part in a 20-week weight loss program.

In Spain lunch is the biggest meal of the day when about 40% of daily calories are consumed.

The study participants were about evenly divided between those who ate lunch before 3 p.m. and those who ate lunch later than that. Energy intake, nutrient composition of the diet, energy expenditure, appetite hormone levels, and sleep patterns were similar between early and late lunchers, but people who ate a late lunch ate lighter breakfasts and skipped breakfast more often than early lunchers.

Late lunchers lost weight more slowly and lost less weight than early lunchers. People who ate a late lunch also tended to eat a later dinner, but neither the timing of breakfast nor dinner were associated with difference in weight loss.

The authors discuss several reasons why eating a late lunch could lead to less weight loss, including the long period between breakfast and lunch, which could lead to impairment in glucose control because the body is in a semi-fasting state. It is not clear if and how these finding generalize to the South African population because we tend to eat more calories for supper than for lunch.