Previous formulations (medical or commercial) of carbohydrate-free very low calorie diets provided 200–800 kcal/day and maintained protein intake, but eliminated any carbohydrate intake and sometimes fat intake as well. These diets subject the body to starvation and produce an average weekly weight loss of . However, the total lack of carbohydrates avoids protein sparing and thus produce a loss of lean muscle mass, as well as other adverse side effects such as increased risks of gout, and electrolyte imbalances, and are thus disadvised. Total diet replacement programs are the modern formulations regulated in Europe and Canada to ensure the recommended daily intake of necessary nutrients, vitamins and electrolyte balance. Compared to older VLCD formulas, the total diet replacements better preserve lean body mass, reduce known side effects and improve .