Approximately 36% of US adults are obese (BMI ≥30 kg/m2), and a majority of US adults are overweight. Obesity and overweight are linked to changes in energy metabolism, blood sugar regulation, and immune function, and are associated with significant health care costs. Recent evidence indicates that the median daily eating window for adults is almost 15 hours, and early studies suggest that narrowing the eating window through TRE presents a simple means of addressing eating habits that affect body composition and long-term health.
TRE is variously applied with maintenance of normal energy intake, energy restriction, or unrestricted energy intake, and it may be combined with exercise or controlled intake of protein. In previous TRE studies not limiting energy intake and not introducing exercise as a variable, TRE has shown beneficial influence on fat mass, visceral fat, glucose tolerance, and insulin sensitivity. The results of TRE research employing resistance exercise or protein supplementation have demonstrated more consistent maintenance or improvement in lean mass.
In this controlled trial, 20 pre-screened, non-diabetic, overweight/obese adults (mean BMI 34.1 kg/m2) with a mean daily eating window of 15.4 hours were randomized to follow their normal eating pattern or an 8-hour eating window for a 12-week study period. Participants were assessed for height, weight, body composition, blood lipid profile, oral glucose tolerance, hemoglobin A1c level, continuous blood glucose values, number of daily eating occasions, and physical activity level prior to and after intervention. Physical activity and continuous glucose monitoring sensors were worn for about 2 weeks to gather data, and eating windows were evaluated via smartphone application (myCircadianClock). Subjects observing TRE freely chose a set 8-hour eating window to follow for the 12-week period, while non-TRE subjects were instructed to eat as usual, and participants received no other eating or dietary instruction. Eating occasions within the eating window were defined as any oral intake other than water or medication for at least 15 minutes apart from other food or drink.
TRE May Help Remodel Eating Behaviors
Time-restricted eating (TRE) is a realistic means of modulating the glycemic influence of food energy through narrowing the daily eating window. Evidence suggests that combining TRE with exercise or protein supplementation may further optimize its metabolic benefits by supporting lean body mass.