The metabolic syndrome is a group of concomitant conditions, including abdominal obesity, elevated blood pressure and hyperglycaemia, which increase a person’s risk for cardiovascular diseases and type 2 diabetes mellitus. Lifestyle interventions, such as reducing calorie intake and exercising, are the first treatment for the metabolic syndrome but are often difficult to adhere to.

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Time-restricted eating (TRE) is a dietary intervention that aims to ensure people maintain a regular daily cycle of feeding and fasting. Studies in rodents suggest that food timing rather than calorie content underlies the beneficial effects of TRE.

“It is difficult for many people to count calories,” explains Pam Taub, one of the corresponding authors of the study. “TRE has given new hope to those involved in treating obesity and metabolic diseases, but it is rarely tested on people who have been diagnosed with metabolic diseases.” Therefore, it was unclear whether patients that are on medications for one or several symptoms of the metabolic syndrome can safely implement TRE and derive additional benefits from it.

To address these questions the researchers recruited 19 patients who had at least three symptoms of the metabolic syndrome for a 12-week TRE intervention. The participants selected a daily, 10-hour window in which to consume all of their calories and used the myCircadianClock app, developed by co-corresponding author Satchin Panda, to log calorie intake. They also wore a wrist activity monitor and a continuous glucose monitor for 2 weeks to track activity and intestinal glucose levels, respectively.

The researchers observed that study participants adapted to the TRE schedule by moderately shifting meal timing rather than skipping meals and that timing of calorie intake became more regular over the course of the study.

Participants lost body weight and experienced improvements in LDL-cholesterol levels, blood pressure and blood glucose values. In addition, none of the participants reported adverse effects while they reduced calorie intake. “Even patients who were already on statins and anti-hypertensive medications further reduced LDL-cholesterol and blood pressure,” reports Taub. The authors note that the metabolic improvements could not be explained solely by changes in weight.

“Future studies should combine nutritional quality and/or quantity with the timing of eating to test their relative contributions to health,” concludes Panda.