[Frequency and timing of meals and changes in body mass index: Analysis of the data from the Adventist Health Study-2].

GOAL: Our study focuses on examining the relationship between the frequency and timing of meals and changes in BMI in the Adventist Health Study-2 (AHS-2) which represents a relatively healthy population in North America.

METHODOLOGY: A longitudinal analysis was undertaken using data from 48 673 individuals monitored over an average period of 7.43 ± 1.24 years. The number of meals per day, length of nighttime fasting, eating breakfast and timing of the largest meal of the day (breakfast 5-11 a.m., lunch noon-4 p.m. or supper/dinner 5-11 p.m.) were used as independent variables. The primary output was the change in body mass index (BMI) once in a year. Linear regression analyses were adjusted for all important demographic factors and lifestyle factors.

RESULTS: Consumption of 1 and 2 meals a day was associated with decrease in BMI (-0.04; 95% CI -0.06 to -0.03 and -0.02; 95% CI -0.03 to -0,01 kg.m-2 per year, respectively). On the other hand, consumption of 3 or more meals a day was associated with increase in BMI, in a linear relation (p < 0.001). BMI of those who skipped breakfast increased (0.029; 95% CI 0.021-0.037 kg.m-2 per year; p = 0.002) as compared to no BMI change in those who had breakfast (-0.0002; 95% CI -0.005 to + 0.004 kg.m-2 per year). Those, whose largest meal of the day was breakfast, recorded no significant change in BMI (-0.002 95% CI -0.008 to +0.004 kg.m-2 per year). On the contrary, the largest supper was associated with the greatest increase in BMI (0.034; 95% CI 0.029-0.040 kg.m-2 per year).

CONCLUSION: Our results indicate that eating less frequently, consuming breakfast and having the largest meal in the morning hours may be effective measures to prevent weight gain.Key words: body mass index (BMI) - frequency and timing of meals - body mass regulation - breakfast.