Intermittent fasting, which consists of alternating periods of eating with those when one does not eat, is very fashionable. But is it really effective for losing weight?
Is it better to stop eating for a short time or pay attention to its line every day? Intermittent fasting would be as healthy and effective as conventional caloric restriction diets, according to new research. To achieve weight loss, everyone can choose the method that suits them best, provided they stick to it rigorously.
"The small studies done so far on intermittent fasting have demonstrated a very positive impact of this method on metabolism," says Ruth Schübel, a researcher at the DKFZ center in Germany. "So we were curious to know if a greater experience would corroborate these results," he says.
Decrease by 20% the calorie intake over the whole week
150 overweight people were recruited. At the beginning of the study, they were randomly classified into three groups. A third of them followed a conventional diet, reducing their daily calorie intake by 20%. The second group followed an intermittent fast allowing them to reduce by 20% the caloric intake over the whole week. The control group did not follow any dietary restrictions. After the diet phase, the researchers provided information on the weight and state of health of the participants for another 38 weeks.
They finally found that the improvement in the state of health was the same with both dietary methods. "In all participants, the body weight and, with it, the unhealthy abdominal fat, were lost.The fat present in the liver has also decreased," says Ruth Schübel. 20% of the dangerous visceral fat and more than a third of the liver fat were lost on average.
Always rely on a balanced diet
Good news for study director Tilman Kühn: "For some people, it seems easier to be very disciplined for two days instead of counting calories and limiting food every day." He specifies however: "to stabilize its weight, it is necessary to be based permanently on a balanced diet". For him, the important thing is not ultimately in the method, but rather in sticking to it. Diets low in carbohydrate or low in fat have also achieved similar results.
Three categories of intermittent fasting
Intermittent fasting alternates periods of fasting and periods of normal feeding. The duration of the fasting phases is flexible. Intermittent fasting patterns can be grouped into three categories:
- Complete fasting or hydraulic fasting, where only water or non-caloric drinks, such as tea or coffee are consumed on days of fasting.
- The intermittent energy restriction, which allows food on days of "fasting altered" but with a much lower caloric intake on fasting days of the order of 20% of normal days, or approximately up to 600 calories.
- Time-limited feeding allows feeding during a restricted window of time each day. As an example: skip breakfast and start eating at noon if your last meal of the day before is at 8:00 pm is a fasting cycle of 16 hours.
22% of the world's population could be obese by 2045
Since 1975, the number of obese people has almost tripled in the world. In 2016, 13% of adults in the world were obese, 39% were overweight. In France, it is estimated that 30% of the population suffers from this condition. 22% of the world's population could be obese in 2045 if the situation does not change.