Facts: About the study
Participants were drawn into one of three groups. Group 1 was allowed to eat between 12:00 and 20:00 without calorie restrictions. Group 2 had to eat 25 percent of their caloric intake and group 3 would not change their eating.
Participants in groups 1 and 2 saw a dietitian regularly, first once a week, then every two weeks for six months. Between six months and a year, they met with a dietitian every four weeks.
The study lasted for one year.
Source: Annals of Internal Medicine
Fasting for parts of the day or some whole days has become a popular method for, among other things, weight loss. To find out if it works as well as counting calories for someone who wants to lose a few kilos, American researchers have compared the different methods.
Overweight people with a body mass index, BMI, between 30 and 50 were randomly assigned to one of three groups. In one, the participants were allowed to eat whatever they wanted between 12 noon and 8 pm. The participants in group two were to reduce their calorie intake by 25 percent and in a third group, the control group, made no changes at all.
Met a dietician
After six months, the fasting people had to eat for another two hours per day and the calorie group had to eat additional calories per day. This is to resemble a kind of real situation where people, according to the researchers, usually keep a stricter diet for six months and then return to eating more as usual.
Everyone in groups one and two also met regularly with a dietitian for a year, first weekly and then less often. There, they received support and advice on choosing healthy foods, among other things. All participants were asked not to make changes in their physical activity but to continue as before.
A total of 77 people completed the study, which was published in the scientific journal Annals of Internal Medicine.
After one year, those who adhered to intermittent fasting had lost an average of 4.6 kilograms more than the participants in the control group and consumed 425 fewer calories per day.
Those who received calorie restrictions lost an average of 5.4 kilograms more than the control group and consumed 405 fewer calories.
The difference in weight loss was not statistically significant between the groups and corresponded to approximately 5 percent of the participants’ original weight.
Choose the easiest way
Krista Varady, professor of nutrition and one of the authors of the study, tells American NPR that “the content of the study is that you can count time as well as calories” and that patients can choose the method that suits them best.
Previous studies examining the effects of different types of intermittent fasting have not shown equally effective results. Here, the fact that the participants regularly met with a dietician as support may have been decisive. At least that’s what two other experts who wrote an annotated article for the study think so.