For body weight loss in general a low-calorie, low-lipid, normal-carbohydrate diet is recommended, even if some nutritionists instead advise a low-carbohydrate diet. A randomized study was then performed, taking into consideration four popular diets: Atkins (strongly low-carbohydrate diet), Zone (low-carbohydrate diet), LEARN (normal-carbohydrate low-lipid diet), Ornish (strongly low-lipid and strongly hyper-carbohydrate diet). Participants were 311 obese, non-diabetic, pre-menopausal women (age range between 25 and 50; 71% of white race; average BMI 32). The compliance with diets after a year resulted similar in all the four groups (76%-88%). After a year, weight loss was higher with Atkins diet (-4,7 kg), followed by Ornish diet (-2,6 kg), by LEARN diet (-2,2 kg) and in the end by Zone diet (-1,6 kg). Only the difference between Atkins and Zone diets was statistically significant. After a year, the Atkins diet gave the greatest increase in HDL cholesterol (averagely 5 mg/dl vs. less than 3 mg/dl with the other three diets), the greatest decrease in triglycerides (29 mg/dl vs. less than 15 mg/dl) and of OSAP (7,6 mmHg vs. less than 4 mmHg for systolic pressure; 4,4 mmHg vs. less than 3 mmHg for diastolic pressure). With Ornish diet it was seen the greatest decrease of LDL cholesterol (4 mg/dl vs. less than 1 mg/dl with other diets). The slight modifications in insulinemia and glycaemia were practically identical in the four groups.
The analysis was exact and, according to these data, a strongly low-carbohydrate diet like the Atkins diet gives the best results as to weight loss and decrease in cardiovascular risk factors, even if the advantage compared to other diets is not significant. It would be also necessary to examine other subgroups of patients (diabetics, people with hypertension, males), before affirming which is the best diet.
