Reproductive-aged women with obesity and insulin resistance have increased risk of type 2 diabetes mellitus and cardiovascular disease, and are also predisposed to adverse pregnancy outcomes, including adiposity and cardiometabolic disorders in their offspring.While a healthy diet and regular physical activity are primary lifestyle strategies for the prevention and treatment of obesity and its associated conditions, poor adherence rates limit their effectiveness. Time-restricted eating (TRE) is a popular dietary strategy that emphasizes the timing of meals in alignment with diurnal circadian rhythms, permitting ad libitum energy intake during a restricted eating window.
Unlike other dietary approaches that modify the feeding-fasting cycle (i.e., chronic energy restriction or intermittent fasting), TRE is a chrono-nutritional strategy in which the timing of meals is closely aligned with typical metabolite and hormonal profiles over 24-h periods. While TRE places no restrictions on total energy intake or the macronutrient composition of food, individuals often spontaneously reduce their energy intake, inducing a mild (1%–4%) body weight loss over intervention periods lasting from 1 week to 3 months.
TRE also improves insulin sensitivity without weight loss in men with overweight and prediabetes and in healthy individuals without obesity. High-intensity interval training (HIIT) performed as short, repeated bouts of high-intensity aerobic exercise separated by low-intensity breaks, is a time-efficient alternative to the current higher-volume physical activity recommendations and improves cardiorespiratory fitness and insulin sensitivity in high-risk populations.
Despite the substantially lower exercise time, HIIT is as effective for weight loss as prolonged, continuous moderate-intensity exercise for obesity treatment. Both HIIT and TRE hold promise as practical diet-exercise strategies to improve metabolic health in reproductive-aged women
A randomized, controlled trial has tested whether combining these two approaches is more effective than either of them on their own.
The trial had four arms: HIT alone, TRE alone, the TRE-HIIT combination, and a control group. A total of 131 women were enrolled, with 32 or 33 in each arm. All of them had overweight or obesity and had risk factors for cardiometabolic diseases like type 2 diabetes and cardiovascular disease. TRE was defined as consuming all daily calories within a 10-hour time window. HIIT was defined as exercise done at 90% of maximum heart rate for 35 minutes, three times per week. The exercise sessions were supervised by the investigators, and the participants were asked to log their first and last calories every day.
The interventions lasted for 7 weeks. Several measures were taken both before and after the study, including the participants’ blood pressure, body mass index, fat and cholesterol levels in the blood, and several measures of blood glucose and insulin levels.
The researchers found that the participants who combined TRE and HIIT were able to improve their average long-term glycemic control measured as HbA1c. They were also able to effectively reduce fat mass and visceral fat and increase their cardiorespiratory fitness measured as peak oxygen uptake. However, there were no statistically significant differences in blood lipids, appetite hormones, or vital signs after any of the interventions compared with the control group.
Another important finding from the study was that adherence to the study was high. This is very important to get great results from a new strategy to decrease weight . This finding highlights the importance of changing both dietary and physical activity habits for individuals who wish to rapidly improve their health and lower their disease risk.
Haganes et al (October 4, 2022). Time-restricted eating and exercise training improve HbA1c and body composition in women with overweight/obesity: A randomized controlled trial. Cell Metabolism. Retrieved from : https://www.cell.com/cell-metabolism/fulltext/S1550-4131(22)00393-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS155041312200393X%3Fshowall%3Dtrue
Photo by Scott Webb on Unsplash.