According to a new study from the University of Illinois at Chicago, two daily fasting diets, also known as time-restricted feeding diets, are effective for weight loss.
The findings are based on a clinical trial that compared a 4-hour time-restricted feeding diet and a 6-hour time-restricted feeding diet to a control group.
Krista Varady, professor of nutrition at the UIC College of Applied Health Sciences and corresponding author of the story, said, “This is the first human clinical trial to compare the effects of two popular forms of time-restricted feeding on body weight and cardiometabolic risk factors.”
Participants in the 4-hour time-restricted feeding diet group were approached to eat just between the long periods of 1 p.m. also, 5 p.m. Participants in the 6-hour time-restricted feeding diet group were approached to eat only between the hours of 1 p.m. also, 7 p.m.
In both the study groups, patients were allowed to eat whatever they wanted during the 4-hour or 6-hour eating period. During the fasting hours, participants were directed to only drink water or calorie-free beverages. In the control group, participants were directed to maintain their weight and not change their diet or physical activity levels.
The participants were followed for ten weeks as weight, insulin resistance, oxidative stress, blood pressure, LDL cholesterol, HDL cholesterol, triglycerides, and inflammatory markers were tracked.
Scientists found that participants in both daily fasting groups reduced calorie intake by about 550 calories each day by merely adhering to the schedule and lost about 3% of their body weight. They also found that insulin resistance and oxidative stress levels were reduced among participants in the study groups when compared with the control group.
Varady said, “The findings of this study are promising and reinforce what we’ve seen in other studies—fasting diets are a viable option for people who want to lose weight, especially for people who do not want to count calories or find other diets to be fatiguing. It’s also telling that there was no added weight loss benefit for people who sustained a longer fast—until we have further studies that directly compare the two diets or seek to study the optimal time for fasting, these results suggest that the 6-hour fast might make sense for most people who want to pursue a daily fasting diet.”
- Sofia Cienfuegos et al., Effects of 4- and 6-h Time-Restricted Feeding on Weight and Cardiometabolic Health: A Randomized Controlled Trial in Adults with Obesity, Cell Metabolism (2020). DOI: 10.1016/j.cmet.2020.06.018