Cutting back on carbohydrates or fats leads to the same weight loss over time, but the low-carb approach increases HDL levels, according to an Annals of Internal Medicine study. Some 300 obese adults (mean body mass index, 36) were randomized either to an Atkins-style, low-carbohydrate diet or to a calorie-restricting, low-fat diet for 2 years. Both groups received more than 35 group behavioral treatments. Weight loss was virtually identical on both diets — 11% of initial weight at the end of the first year and roughly 7% at 2 years. Of note, HDL levels rose more on the low-carbohydrate regimen and remained higher at the 2-year mark. This is only one reason why I always tell my patients that diets are not healthy. The main reason being that diets always have an end which is why within 2 years, the original weight lost is gained back plus 10%. However here is a physiological reason why a low fat diet does not work. Yes, you lose weight, but at the same time do not lower your HDLs. Think Moderate Protein, Low Fat , Low Carbs.