A 12-week Johns Hopkins Medicine trial reveals that time-restricted eating achieves similar weight loss results as flexible eating patterns, challenging claims of fasting’s superiority for weight management.
A Johns Hopkins Medicine study published in the journal Obesity suggests that intermittent fasting is no better than a conventional eating pattern for weight loss when total calories are the same. In a 12-week trial involving 39 adults with obesity, most of them women, researchers compared a time-restricted plan with a more flexible schedule and found that both groups lost roughly the same amount of weight.
The study included people with obesity, pre-diabetes or diet-controlled type 2 diabetes. One group ate all of its daily food within a 10-hour window, beginning with breakfast in the morning and finishing dinner in the early evening. The other group could eat throughout the day, provided meals were not taken overnight and dinner ended by 8pm. Both groups received diets with the same calorie level and the same balance of protein, fat and carbohydrates.
After three months, participants in both groups had shed about 2.5% to 2.7% of their body weight, indicating that restricting the hours available for eating did not deliver extra weight-loss benefit on its own. The researchers also reported no meaningful differences in appetite-related hormones or inflammation markers between the two approaches.
There was, however, some variation between individuals. Johns Hopkins researchers found that among those following the 10-hour eating window, some people appeared less prone to uncontrolled overeating, while others showed little change. That suggests meal timing may affect people differently, even if the average result across the group was the same.
The findings fit with a broader body of research that has often found intermittent fasting to be roughly comparable with continuous calorie restriction rather than clearly superior. A 2023 meta-analysis of randomised controlled trials, for example, found no significant advantage for intermittent fasting in body weight, body mass index, blood glucose, cholesterol or blood pressure. Earlier reviews have been more mixed, with some suggesting the approach can be an effective weight-loss option, although many also called for more evidence on long-term outcomes, psychological effects and the best way to use the diet in practice.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
