Abstract: It has been discovered that the unfavorable effects observed in weight reduction treatments based on severe dietary restriction (less than 600 Kcals/day) or total fasting (as regards fat, carbohydrates and aminoacids) are avoided by the administration of aminoacids and carbohydrates in critical but much lower amounts than has been believed to be necessary. Nitrogen loss with aminoacid intake between about 15 g and 30 g per day is affected by carbohydrate intake. Nitrogen balance is maintained and ketosis and water retention are controlled when the daily intake includes, in addition to necessary minerals and vitamins, at least 15 g of aminoacids in the proportions required by man, and from 15 g to 75 g, preferably 30 g to 45 g, of carbohydrates, with a total caloric value of from 160 to about 600 Kcals, preferably less than 400 Kcals, very desirably less than 360 Kcals, and optimally in the range of from 180 to 360 Kcals.