Time-restricted eating

As the new year begins, many people focus their attention on their eating habits as they resolve to lose unwanted weight and improve their health¹. Unfortunately, evidence-based advice about the most effective ways to lose weight (and keep it off) can be hard to come by. That’s a shame because individualised programs are the best ways to help people achieve their weight loss goals. 

“There is increasing recognition that tailored weight loss advice greatly enhances the likelihood of long-term weight loss success, as certain strategies work better for some individuals over others”².

Fundamental differences in body composition and metabolism between men and women suggest tailoring weight loss approaches to an individual’s sex might be advantageous. However, when it comes to studies of weight loss, men are underrepresented, and data are often not reported by sex⁵.

Men may be less likely than women to try to lose weight^3, but they seem to be more successful when they try. Whether it be through dieting alone, or diet and exercise, men lose more weight than women⁴, and men are more likely than women to complete weight loss interventions than women⁵.

The male advantage when it comes to weight loss has been demonstrated specifically for both low-calorie⁶ and low-carbohydrate diets².

It appears individual support or tailored advice are more effective for helping men to lose weight than group-based programs, and men benefit from the support of their spouse or partner⁵.

Time-restricted eating

Recently, evidence has accumulated to demonstrate that when we eat, not just how much we eat, can contribute to weight loss (and gain). In fact, there are multiple potential health benefits of limiting eating to only part of each day, so there is a fasting period of at least 12 hours⁷. 

A recent randomised controlled trial of time-restricted eating showed beneficial effects on weight loss, blood pressure and mood, but data were not disaggregated by sex⁸. Another randomised controlled trial of time-restricted eating similarly fails to mention effects of the sex of subjects, even though it’s titled, ‘Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity’⁹! Participant sex is not mentioned in relation to statistical analysis, suggesting this important determinant of the study’s outcomes has been disregarded.

A trial of time-restricted eating in a small number of men with obesity and prediabetes showed beneficial effects on insulin sensitivity, blood pressure and oxidative stress (but not cholesterol or inflammatory markers) of eating over a 6-hour, rather than 12-hour period, in the absence of weight loss¹⁰.

The failure of most studies of time-restricted eating to report results separated by gender means the safety and efficacy of this promising approach to improving health is incompletely understood and limits the certainty of advice to those whom it may help.