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SALT LAKE CITY — High-intensity exercise and time-restricted eating may do more for cardiometabolic health and weight loss than either approach alone, according to a new study published in PLOS ONE.
High-intensity exercise combines intense aerobic exercise with resistance exercise. Time-restricted eating limits the hours in which someone eats but not what is eaten.
Researchers from the University of Sfax, Tunisia, looked at both practices, separately and together, and measured the impact on body composition and markers of cardio-metabolic health, including cholesterol, blood glucose and lipid levels, assigning 65 female study subjects ages 22 to 42 who had obesity to one of the three groups. The time-restricted eating group could eat only between 8 a.m. and 4 p.m. The high-intensity functional training group worked out three days a week with an instructor. The third group did both.
According to the study, "Obesity is a critical clinical and public health issue as it is associated with an increased risk of cardiovascular disease, insulin resistance, cancer, oxidative stress and osteoarthritis." The authors wrote that while changes in diet and exercise are known to reduce weight, figuring out what yields the best results is difficult.
After 12 weeks, the researchers found that all three groups "had significant weight loss and decrease in waist and hip circumference," according to a news release posted on Science Daily. They also enjoyed positive changes in their lipid and glucose levels.
"We can highlight in this study that time-restricted eating is a good solution to combat obesity, easy to implement since it does not require people to limit their overall food intake or count the total number of daily calories," the study's corresponding author, Rami Maaloul, said in a written statement from PLOS One. "In addition, sport has a fundamental role in preventing weight gain."
Fat-free mass — defined as a combination of lean mass and skeletal muscle mass — and blood pressure both got better in the exercise group and in the combination group, but not for those who only practiced time-restricted eating. The researchers noted that indicates it reduces fat mass without reducing muscle mass. "This finding may help to explain why time-restricted eating could improve metabolic dysfunction in obese people, as muscle mass plays a crucial role for resting metabolism, glucose regulation and maintaining skeletal integrity."
The study noted that other research on time-restricted eating showed a significant reduction in muscle mass, suggesting that combining time-based eating with exercise "is a recommended strategy to mitigate the risk of unhealthy lean mass loss and to improve the functional physical capacities of inactive adults with obesity during the weight-loss process."
The biggest changes were found in the group that combined both time-restricted eating and high-intensity exercise. For "inactive women with obesity, combining time-restricted eating and high-intensity functional training can be a good strategy to induce superior effects on body composition, lipid profile and glucose regulation compared with either diet or exercise intervention alone," they concluded.
But they point out that it's a small study, and further research is needed.
