Which Diet is Best for Permanent Weight Loss?

The New England Journal of Medicine conducted research to establish the most effective dietary regime. They studied three popular weight loss plans;

1) Low-Fat Diet.....'stickability' over 2 years 90.4%

The low-fat, restricted-calorie diet was based on American Heart Association guidelines. They aimed at an energy intake of 1500 calories  per day for women and 1800 calories per day for men, with 30% of calories from fat, 10% of calories from saturated fat, and an intake of 300 mg of cholesterol per day. The participants were counselled to consume low-fat grains, vegetables, fruits, and legumes and to limit their consumption of additional fats, sweets, and high-fat snacks. Average weight loss over 2 years (-3.4kg).

2) Mediterranean Diet......'stickability' over 2 years 85.3%

The moderate-fat, restricted-calorie, Mediterranean diet was rich in vegetables and low in red meat, with poultry and fish replacing beef and lamb. They restricted energy intake to 1500 calories per day for women and 1800 calories per day for men, with a goal of no more than 35% of calories from fat; the main sources of added fat were 30 to 45 g of olive oil and a handful of nuts (five to seven nuts, <20 g) per day. The diet is based on the recommendations of Willett and Skerrett. Average weight loss over 2 years (- 4.0kg).

3) Low-Carbohydrate Diet......'stickability' over 2 years 78%

The low-carbohydrate, non–restricted-calorie diet aimed to provide 20 g of carbohydrates per day for the 2-month induction phase and immediately after religious holidays, with a gradual increase to a maximum of 120 g per day to maintain the weight loss. The intakes of total calories, protein, and fat were not limited. However, the participants were counselled to choose vegetarian sources of fat and protein and to avoid trans fat. The diet was based on the Atkins diet. Average weight loss over 2 years (- 4.9kg).

The results over a 24 month period seem to support the 'no gain without pain' axiom. The diet which participants found hardest, (with only 78% sticking to the low-carbohydrate regime), was also the most effective with an average weight loss of  4.9kg,  as compared to 3.4kg for a low-fat diet.  

John McNally