A popular fasting diet called the 5:2 or “Fast Diet” may actually be better than traditional calorie-restricting diets for heart health. Scientists from the University of Surrey found recently that the 5:2 diet lowered levels of fat in the blood and reduced blood pressure.
The 5:2 diet was popularized by British doctor and journalist Michael Mosley. The diet contains no requirements about which foods to eat, only about when you should eat them. Five days of the week are normal eating days, and the other two days of the week restrict calories to 500-600 per day, with at least one non-fasting day in between the two restricted calorie days.
In a unique new study, researchers compared the effects of both the 5:2 diet and a traditional daily calorie restriction diet on metabolism and clearing fat from the blood after eating. Unlike past studies, the present project shifted attention away from blood risk markers taken in the fasted state.
Researchers recruited overweight study participants who were randomly assigned to either the 5:2 diet or the traditional diet. Those on the traditional diet advised to eat 600 calories or less per day than their estimate requirements for weight maintenance (for women, 1400 calories, for men, 1900 calories).
Those on the 5:2 diet successfully lost five percent of their weight in an average of 59 days, while those on the daily calorie restriction diet took an average of 73 days to lose the same amount. Researchers found that the participants on the 5:2 diet cleared a fat called triglyceride from a meal given to them more efficiently than the participants on the daily restriction diet.
Additionally, researchers saw a larger decrease in systolic blood pressure in the participants on the 5:2 diet, a well-studied risk factor for cardiac events like heart attack and stroke.
Twenty percent of patients from both groups dropped out because they either could not tolerate the diet or could not lose five percent of their weight at the beginning of the study. Researchers are working on ways to make the 5:2 diet more tolerable.
“For those who do well and are able stick to the 5:2 diet, it could potentially have a beneficial impact on some important risk markers for cardiovascular disease, in some cases more so than daily dieting,” explained the University of Surrey’s Dr. Rona Antoni. “However, we need further studies to confirm our findings, to understand the underlying mechanisms and to improve the tolerability of the 5:2 diet."
The present study was published in the British Journal of Nutrition.