People frustrated trying to lose weight by cutting calories every day may be encouraged to hear that intermittent fasting might be more effective.
In a new study published Monday in Annals of Internal Medicine, people who fasted during three nonconsecutive days a week and ate whatever they wanted on the other days lost modestly more weight compared with those who restricted their calorie intake every day of the week. These findings were significant because previous studies have reported no notable difference between the two diet strategies, the researchers said in a news release.
“It was surprising and exciting to me that it was better,” said Dr. Victoria Catenacci, one of the study's authors and an associate professor of endocrinology at the University of Colorado School of Medicine. “The more important message to me is that this is a dietary strategy that is an evidence-based alternative, especially for people who have tried DCR (daily calorie restriction) and found it difficult.”
The new study included 165 people ages 18 to 65 who were overweight or obese. The intermittent fasting group cut 400 to 700 calories, depending on body size, three days a week. They ate normally the other days with a focus on healthy food. The dieting group cut about 34% of calories every day. The total caloric reduction for both groups was about the same per week. But at the end of a year, the people who followed an intermittent fasting plan known as 4:3 lost an average of 7.6% of their body weight, compared with an average of 5% of body weight loss in the group restricting calories every day.
Previous research did not have such delineated results. A 2022 study, for instance, found that intermittent fasting was not more effective than daily calorie restriction. A study from 2023 reported that intermittent fasting was as effective as calorie restriction over a 12-month period.
With more than 2 in 5 adults in the United States having obesity – more than 100 million people – it has become a public health issue, according to the Centers for Disease Control and Prevention. Obesity can lead to chronic health concerns including high blood pressure and cholesterol, Type 2 diabetes, anxiety and depression. Adults with obesity also have a higher risk of many types of cancer, stroke and premature death.
Intermittent fasting is safe for many people, but it may not be a healthy dieting approach for people who are pregnant or breastfeeding, people at high risk of bone loss and falls, and people who have eating disorders, according to the Mayo Clinic. People should talk to a health care provider before trying intermittent fasting, the Mayo Clinic said.
