Pooled Analysis Links 8-Hour Eating Window to Greater Weight Loss

Researchers analyzing pooled data from five clinical trials have found that an eight-hour time-restricted eating window yields greater weight loss than a twelve-hour window or control diets, though cardiometabolic benefits remained largely constrained. The study, published in the journal Nutrition and Diabetes, examined 124 adult participants who had a baseline habitual eating window of at least 14 hours and at least one component of metabolic syndrome.

Participants assigned to time-restricted eating regimens limited their daily food and beverage consumption to 8, 10, or 12 hours without receiving specific caloric prescriptions or dietary restrictions. Across the intervention groups, participants reduced their daily eating windows by an average of about four hours and achieved an average weight loss of 2.18 kilograms compared to baseline measurements. Control groups, which maintained ad libitum intake or received general nutritional guidance, did not exhibit significant reductions in their eating windows or body weight.

When evaluating specific regimen durations, individuals assigned to the eight-hour eating window lost more weight than those on the twelve-hour schedule or control groups. However, the weight loss difference between the eight-hour and ten-hour cohorts did not achieve statistical significance. Statistical modeling indicated that shorter actual eating windows during follow-up correlated with increased weight loss, but adjusting the models for baseline body mass index, age, and sex attenuated these associations.

Regarding secondary cardiometabolic outcomes, participants assigned to a ten-hour eating window demonstrated greater decreases in systolic blood pressure compared to those on a twelve-hour regimen. The study found no other significant alterations in blood pressure, fasting plasma glucose, or lipid profiles across the differing allocated eating durations. Researchers noted that the majority of study participants did not have diabetes and presented with normal fasting glucose levels at baseline, a factor that may have limited the detection of measurable improvements in glucose regulation.

Trials evaluated in the pooled analysis lasted between three and six months and were conducted across three centers in the United States and two in Europe. Participants utilized mobile applications to log daily dietary and beverage intake, while researchers tracked body weight, blood pressure, fasting plasma glucose, triglycerides, and high-density lipoprotein cholesterol. Low-density lipoprotein cholesterol was calculated using the Friedewald equation in four of the participating investigations.

Study authors acknowledged multiple methodological limitations within the pooled dataset. The investigation relied on a small overall sample size drawn from a limited number of trials with small individual study groups and notable heterogeneity across protocols. Furthermore, the research lacked quantification of daily caloric intake, omitted eating windows shorter than eight hours, and did not adjust statistical models for multiple comparisons. Race and ethnicity data were also omitted due to inconsistent collection across the original trials, underscoring the need for longer-term investigations involving diverse populations.