Effects of 8-hour time restricted feeding on body weight and metabolic disease risk factors in obese adults: A pilot study

Abstract

Background: Time restricted feeding decreases energy intake without calorie counting and may be a viable option for weight loss. However, the effect of this diet on body weight in obese subjects has never been examined.

Objective: This study investigated the effects of 8-h time restricted feeding on body weight and metabolic disease risk factors in obese adults.

Design: Obese subjects (n = 23) participated in an 8-h time restricted feeding intervention (ad libitum feeding between 10:00 to 18:00 h, water fasting between 18:00 to 10:00 h) for 12 weeks. Weight loss and other outcomes were compared to a matched historical control group (n = 23).

Results: Body weight and energy intake decreased in the time restricted group (-2.6% ± 0.5; -341 ± 53 kcal/d) relative to controls over 12 weeks (P < 0.05). Systolic blood pressure decreased in the time restricted feeding group (-7 ± 2 mm Hg) versus controls (P < 0.05). Fat mass, lean mass, visceral fat mass, diastolic blood pressure, LDL cholesterol, HDL cholesterol, triglycerides, fasting glucose, fasting insulin, HOMA-IR, and homocysteine were not significantly different from controls after 12 weeks (no group×time interaction).

Conclusion: These findings suggest that 8-h time restricted feeding produces mild caloric restriction and weight loss, without calorie counting. It may also offer clinical benefits by reducing blood pressure.

Keywords: Time restricted feeding; body weight; intermittent fasting; metabolic disease risk factors; obese adults.

Fig.1

Study flow chart.

Fig.2

Weekly adherence to the 8-hour feeding window by the time restricted feeding group. All values reported as mean ± SEM. Each bar indicates the mean number of days per week that the time restricted feeding subjects were compliant with the 8-hour feeding window. On average, the time restricted feeding group was compliant with the prescribed eating window (10:00 to 18:00 h) on 5.6 ± 0.3 d/week, and this level of adherence did not change over the course of the trial (P = 0.86, repeated measures ANOVA).

Fig.3

Weight loss by the time restricted feeding group versus controls ¹. ¹All values reported as mean ± SEM. Data were included for 46 participants; means were estimated using an intention-to-treat analysis using last observation carried forward. Body weight remained stable during the 2-week baseline period (week B1 and week B2). Body weight decreased in the time restricted feeding group relative to controls during the 12-week intervention period (P < 0.001 for time × group interaction).