Weight Loss Efficacy of 4-Hour Versus 6-Hour Time Restricted Feeding in Adults with Obesity

Abstract

Objectives: This study was undertaken to compare the effects of 4-h TRF to that of 6-h TRF on body weight, body composition, and metabolic disease risk factors in adults with obesity. We hypothesized that 4-h TRF would produce the greatest decreases in body weight, fat mass, blood pressure, and insulin resistance, compared to 6-h TRF. Methods: Adults with obesity (n = 49) were randomized to Results: Body weight decreased similarly in the 4-h TRF group (-3.3 ± 0.5%) and 6-h TRF group (-2.6 ± 0.5%) relative to controls over 8 weeks (P < 0.001). Fat mass, blood pressure and insulin sensitivity also decreased in the 4-h TRF and 6-h TRF groups versus controls. LDL cholesterol, HDL cholesterol, triglycerides, fasting glucose, and HbA1c were not significantly different from controls after 8 weeks. Conclusions: This is the first trial to examine the effects of 4-h vs. 6-h TRF on body weight and metabolic disease risk factors. We show here that 8 weeks of 4-h and 6-h TRF decreases body weight by ∼3-4% relative to controls. We also demonstrate that this fasting regimen produces significant reductions in blood pressure, fat mass, insulin and insulin resistance. These preliminary data offer promise for the use of 4-h and 6-h TRF as a weight loss techniques in adults with obesity, but larger, longer-term trials are needed to confirm these findings.