Intermittent fasting has generated much excitement over its potential as a simple method to lose weight and improve health. It involves eating normally during limited hours each day (e.g. 8 hours), and then abstaining from food the other hours (e.g. 16 hours). However, a recent study found that people following intermittent fasting for 12 weeks did not really lose weight or improve key metabolic markers. Bummer.
University of California researchers randomly assigned 116 adults, who were overweight or obese, to either an intermittent fasting group (16 hours fasting/8 hours allowed to eat ) or a group that ate 3 regular meals at set times each day (breakfast, lunch, dinner). The intermittent fasting group lost 2 pounds over the 12 weeks, which is not significantly different from the group that ate their meals at structured times - they lost 1 1/2 pounds. Same with metabolic markers (e.g.insulin levels, fasting glucose levels, cholesterol levels) - no real differences between the groups after 12 weeks.
Of course this was just 1 study, so we'll see what other human studies find. In contrast, other small human studies, as well as mice studies, have found health benefits from intermittent fasting, also called time restricted eating.
From Medical Xpress: Intermittent fasting is popular—but it doesn't work for weight loss
The currently popular diet of intermittent fasting that restricts eating to eight hours per day, separated by 16 hours of fasting, is not effective on its own as a means of either losing weight or for improving key metabolic health markers, according to a new study led by researchers at UC San Francisco.
While time-restricted feeding has been shown to prevent weight gain in mice on a high-fat diet and reduces weight and metabolic outcomes in already obese mice, most of the reported benefits of such fasting in humans has had limited scientific testing.
This study, which included 116 men and women with a body mass index (BMI) of 27 to 46, found that people who were randomly assigned to only eat during an eight-hour period each day lost 2 lbs. (0.94 kg) on average over the 12-week period, while those with consistent meal timing lost an average of 1.5 lbs. (0.68 kg).
The study found no significant difference between the two groups in total weight loss or in other markers, such as fat mass, lean mass, fasting insulin or glucose, HbA1C levels, energy intake, or total or resting energy expenditure.