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Fasting diets are effective for weight loss

The results of a new study suggest that a fasting diet may be a welcome alternative to counting calories and having to avoid certain foods

Researchers at the University of Illinois at Chicago analyzed the outcome of daily fasting diets and found that they were effective for weight loss and provided other health benefits as well.

The investigation was designed to compare a 4-hour time-restricted feeding diet, a 6-hour time-restricted feeding diet, and a control group with no dietary restrictions.

Study co-author Krista Varady is a professor of Nutrition at the UIC College of Applied Health Sciences.

“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,” said Professor Varady.

Participants in the 4-hour time-restricted feeding diet group were instructed to eat only between the hours of 1 and 5 p.m, while those in the 6-hour group were instructed to eat between the hours of 1 and 7 p.m.

In both groups, the participants could eat whatever they wanted during the established eating period. During fasting hours, they were asked to drink only water or calorie-free beverages.

Meanwhile, individuals in the control group did not change their diet or physical activity levels in any way.

Over ten weeks, the researchers regularly monitored weight, insulin resistance, oxidative stress, blood pressure, cholesterol, triglycerides, and inflammatory markers among the volunteers.

The study revealed that participants in both daily fasting groups reduced calorie intake by an average of 550 calories a day simply by adhering to the time-restricted eating schedule. These individuals lost about 3 percent of their body weight. 

Compared with the control group, the fasting dieters were found to have reduced levels of insulin resistance and oxidative stress.

The experts also noted that there was no significant difference in the health or weight loss outcomes between the 4-hour and 6-hour fasting groups.

“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,” said Professor Varady. 

“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.”

The study is published in the journal Cell Metabolism.

By Chrissy Sexton, Staff Writer



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