Want to lose weight? Researchers report that intermittent fasting appears to be comparable to traditional restrictive diets — and one form is better than the rest.
Intermittent fasting refers to a diet in which people reduce the number of hours they eat in a day. Benefits to this strategy have previously been identified by physicians. After hours without food, the body exhausts its sugar stores and starts burning fat, according to Johns Hopkins Medicine.
In the U.S., two in five adults are living with obesity, and the condition costs America’s healthcare system nearly $173 billion a year. People who are obese have a higher risk of serious chronic conditions, including cardiovascular disease and diabetes.
Now, doctors and researchers at the Harvard T.H. Chan School of Public Health and other international institutions are adding to prior analysis, finding in a new study that alternate-day fasting also demonstrates greater benefits compared with just curbing calories and other intermittent fasting strategies. Alternate-day fasting means a day-long fast on alternate days.
“Of all forms of intermittent fasting, alternate day fasting — in which a person fasts for a full day, every other day — was most effective,” Harvard said in a statement announcing the findings.
The research was published recently in the journal in The BMJ.
To reach the conclusions, the authors analyzed the health of more than 6,500 adults in 99 clinical trials. Nearly 90 percent were obese and had existing health conditions. The trials ranged in length from between three weeks and just around a year.
All intermittent fasting strategies and may lead to small reductions in body weight compared with a calorie deficit. However, alternate-day fasting demonstrated superior results, resulting in 2.8 pounds greater weight loss compared to traditional calorie-restricted diets in addition to improvements in several other body measurements related to cardiometabolic risk. Those include waist circumference, cholesterol and triglyceride levels, and c-reactive protein- an indicator of inflammation.
Alternate-day fasting was tied to lower levels of total and “bad” cholesterol. Bad cholesterol increases the risk of heart attack and stroke.
“However, these differences did not reach the minimally important clinical threshold of at least [4.4 pounds] of weight loss for individuals with obesity, as defined by the study authors,” they noted in a release.
They said that longer duration trials are needed to further substantiate their findings, and that intermittent fasting is not the right dietary choice for everyone, despite its potential effectiveness.
“As with any dietary change, it is important to consult with health care providers and to consider one’s medical history, dietary preferences, social environment, and realistic long-term compliance,” Zhila Semnani-Azad, postdoctoral research fellow in the Department of Nutrition and the study’s lead author, noted.
