Meal consumption in the evening is greater in obese adolescents compared with overweight or normal weight subjects, with later circadian phase of peak intake and lower amplitude, according to study results presented at World Sleep 2019, held September 20 to 25, in Vancouver, Canada.

Previous studies have shown an association between earlier meal timing and lower weight, reduced weight gain, and greater weight loss. However, limited data are available on the association between caloric intake across the circadian cycle and time across the waking days with body weight. In the study, the researchers used 28 hour forced desynchrony and explored the effects of caloric intake across days that are in alignment or misaligned with circadian phase.

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The study cohort included 51 participants aged 12 to 15 years (29 were men). All participants completed 7 28 hour forced desynchrony cycles in dim light, with 6 meals given at fixed times in each cycle: the first at 1.7 hours after scheduled awakening, the second 2 hours later, and the remaining 4 meals at 3-hour intervals. The participants selected the foods approximately 1 hour prior to each meal from a fixed menu and the food items were weighed before and after each meal.

The researchers calculated the percentage of energy intake for each meal across each waking episode relative to total energy consumed in the forced desynchrony cycle.

Participants were classified according to body mass index (BMI) percentiles: normal weight (>5th and <85th; n=24), overweight (≥85th and <95th; n=13), or obese (≥95th; n=14).

Salivary melatonin levels were used to determine endogenous circadian period in each of the 3 weight categories: normal weight (mean period 24.19h), overweight (mean period 24.23h), and obesity (mean period 24.22h).

The effect of circadian phase and time since scheduled awakening was assessed by Repeated Measures ANOVAs using 6 circadian and 6 time-awake bins. Results indicated a significant influence of time awake (F5, 2086=113.5, P <.01) with differences by weight category (F10, 2076=4.9, P <.01): among obese adolescents more consistent consumption was evident across the day and the relative caloric intake in the last meal of the day was greater compared with overweight and normal-weight subjects.

Circadian phase had a significant effect (F5, 2086 =38.08, P <.01) that was different between weight categories (F10, 2076 =2.75, P <.01). Among obese adolescents, there was evidence of lower amplitude and later acrophase.

Analysis of aligned (forced desynchrony cycle 1) and misaligned (forced desynchrony cycle 4) days showed that alignment had a significant effect (F5,550 =14.32, P <.01) that was different between weight categories (F 10, 528 =2.21, P =.02), as on aligned days consumption at the end of the day was lower and the difference was less significant among obese patients.

“The [obesity] group showed higher consumption in the evening and at a later circadian phase compared to other weight groups. The circadian phase of peak intake was later, amplitude lower, and misalignment influences weaker for [the obesity] group compared to [the overweight] and [the normal-weight] groups,” concluded the researchers.

Reference

Carskadon M, Barker D, Hart C, Raynor H, Mason I, Scheer F. Caloric intake in normal weight, overweight, and obese adolescents: circadian and homeostatic influences measured from 28-hour forced desynchrony (FD). Poster presented at: World Sleep 2019; September 20-25, 2019; Vancouver, Canada; Poster 169.