Intermittent fasting is one of those diet strategies that seems to trend time and again. It’s a simple concept: Only eat during certain hours of the day, also known as an eating window. Plenty of athletes are fans of the diet, claiming that it has tons of benefits aside from weight loss. Turns out, they may be on to something.
A recent study published in Cell Metabolism found that two popular forms of the diet—a 4-hour eating window and a 6-hour eating window—are both effective when it comes to weight loss.
Researchers separated study participants into two groups. One group was told to eat only between 1 p.m. and 5 p.m., while the other ate between 1 p.m. and 7 p.m. They were allowed to eat whatever they wanted in those time frames, but could only drink water or zero-calorie beverages for the rest of the day. A control group maintained their weight and usual diet and exercise routines.
After 10 weeks, both of the fasting groups had eaten about 550 less calories than usual each day without actually counting calories. They also lost 3 percent of their body weight on average. Compared to the control group, the fasting groups also had lower insulin resistance and oxidative stress levels by the end of the study.
“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,” Krista Varady, study author and professor of nutrition at the UIC College of Applied Health Sciences, said in a release.
In the end, there wasn’t a notable difference between the weight loss or overall health results of the 4-hour fasting window group and the 6-hour fasting window group. That’s good news for anyone who would rather get an extra couple hours of eating in every day.
“It’s also telling that there was no added weight loss benefit for people who sustained a longer fast,” Varady said. “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.”
