There is a lot of debate as to what diet is most effective for weight loss. In recent years high-protein diets have taken the limelight. This is mostly a reaction to several studies that showed that high-protein diets resulted in more weight loss over 3-6 months than high-carbohydrate low-fat diets. A smaller group of studies attempted to follow subjects for 12 months or more and found that there was no difference between groups that tried to lose weight on a high-protein diet and those that followed a higher carbohydrate diet.
A Harvard study was conducted with 800 overweight and obese people who followed one of four diets for two years. Each diet lead to a 750 calorie deficit (subjects burned 750 calories more than they ate) and varied in the amount of protein, carbohydrates and fats. The diets were equally successful in promoting weight loss and maintaining it over the two years. In addition, they had similar effects on decreasing disease risk and improving cholesterol levels. The Harvard study emphasized behavioral counseling and support group activities in all four weight loss groups. The authors suggested that the behavioral factors had a greater influence on successful weight loss than the amount of carbohydrates, fats or proteins because the behavioral and support elements of the plan helped the people to stay with their diets and to make permanent changes.
This is encouraging because it makes sense that no one weight loss plan would work for everyone. So the bottom line is that regardless of whether you decrease carbohydrates or fats or proteins you must also make permanent changes and you must decrease the calories you take in and increase the calories you burn to lose weight and keep it off. Find a plan to do this that works for you and you will achieve your goals.