Eating only during a limited window of time each day — known as time-restricted eating or intermittent fasting — had no added benefit on measures of nonalcoholic fatty liver disease (NAFLD) over simply reducing calorie consumption, according to a new study published in the journal JAMA Network Open.
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Previous research has shown that time-restricted eating may have a number of different health benefits, some of which apply especially to people with diabetes. It may help with weight loss and lower blood pressure — and while some studies have show that it’s effective for weight loss, others have found no weight loss benefit. Intermittent fasting has been shown to help lead to remission of type 2 diabetes, or having normal blood glucose levels without taking any glucose-lowering drugs. Intermittent fasting may help improve blood glucose levels even without any weight loss, and even an intermittent low-calorie diet — rather than not eating for extended periods — has been shown to help improve blood glucose control and reduce cardiovascular risk in people with type 2 diabetes.
For the latest study, researchers randomly assigned 88 participants with obesity and NAFLD to one of two dietary interventions for 12 months — eating only between 8 a.m. and 4 p.m., or following normal meals times. Both groups were instructed to consume 1500 to 1800 calories daily for men, and 1200 to 1500 calories daily for women. The main outcome the researchers were interested in was liver fat as measured by magnetic resonance imaging (MRI), and other outcomes that were recorded included any changes in body weight, body fat, and waist circumference. The average age of participants was 32, and 49 (56%) were men. There were 45 participants in the time-restricted eating group, and 43 in the group with normal mealtimes.
No added benefit of intermittent fasting found for NAFLD
After six months, liver fat levels decreased by an average of 8.3% in the time-restricted eating group and 8.1% in the group with normal mealtimes. After 12 months, compared with the beginning of the study, liver fat was down by an average of 6.9% in the time-restricted eating group and 7.9% in the group with normal mealtimes — meaning that members of the time-restricted eating group gained back more liver fat. At both points in time, though, the researchers found that changes in liver fat were comparable in the two groups. Certain other measures were also improved at comparable levels in both group, including liver stiffness, body weight, and metabolic risk factors like blood glucose and lipid (cholesterol and triglyceride) levels.
The researchers concluded that in this group of adults with obesity and NAFLD who followed a reduced-calorie diet, there was no added benefit to restricting the window of time in which participants ate each day. “These findings support the importance of caloric intake restriction when adhering to a regimen of [time-restricted eating] for the management of NAFLD,” they wrote.
Want to learn more about intermittent fasting? Read “Can Diabetics Do Intermittent Fasting?”
Want to learn more about protecting your liver? Read “Diabetes and NAFLD,” “Preventing Fatty Liver (NAFLD),” and “Hepatitis C and Diabetes: Is There a Link?”
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