Losing weight: What works better – intermittent fasting or calorie counting?

Researchers analyzed data from 99 studies involving 6,582 adults. 66 percent of the participants were female, the average age was 45, the average baseline BMI was 31, and almost 90 percent had health problems. The fasting or dieting period ranged from three to 52 weeks (an average of twelve weeks).

Various forms of intermittent fasting were examined, which could be roughly divided into three forms:

These fasting methods were compared with a classic calorie restriction diet, i.e., a calorie-reduced diet, and with a diet without any restrictions. The results of the meta-analysis were published this week in the British Medical Journal .

All intermittent fasting and continuous energy restriction strategies resulted in modest weight loss compared to a full-fledged diet, according to the initial findings. Alternating-day fasting was the only intermittent fasting strategy that showed a small benefit in reducing body weight compared to traditional continuous calorie restriction (mean difference: minus 1.29 kg). This form of fasting also performed slightly better than the other two intermittent fasting methods, time-restricted eating and all-day fasting (mean differences: minus 1.69 kg and minus 1.05 kg, respectively).

However, the differences did not reach the minimal clinical threshold of at least 2 kg weight loss defined by the study authors for individuals with obesity. And the benefits were only evident when fasting was continued for at least 24 weeks.

Alternating fasting was also associated with a slightly greater reduction in total cholesterol and LDL cholesterol compared to time-restricted eating. The latter even led to a small increase in cholesterol compared to all-day fasting. Neither method had any advantages regarding blood sugar levels or HDL cholesterol.