In obesity resistant to traditional low calory diets, the authors alternated short periods of moderate low calory intake (600 to 1,000 calories) with periods of very restrictive low calory intake (230 to 300 calories). The results of this method are analysed in 105 patients. This method permits loss of weight in difficult cases of obesity, both during intensely low calory diets and during less severe low calory diets. This technique is well accepted by the patients and is less monotonous than very unbalanced multi-fractionated diets or with prolonged courses of fasting. The results are all the more satisfactory when the patient is young, when the obesity is recent and marked, which does not, however, exclude its efficacy in long-standing cases of obesity.