The latest issue of the Annals of Internal Medicine contains a discussion about the impact of weight loss counseling.

An analysis of multiple studies found that over the period of one year, weight loss counseling combined with a calorie-restricted diet resulted in net loss of approximately two BMI units (6%), or about 10-15 pounds. After a period of three years, however, about half of lost weight was regained.

But, there is a big asterisk that needs to be noted - the article's authors said there were problems with the data and more studies are needed. Specifically, the authors stated:
Although the results of our meta-analysis and meta-regression add new information that previous systematic reviews on this topic (9–17) have not provided, our study has several limitations. The most important limitation is uncertainty in the magnitude of the net treatment effect caused by the clinical and statistical heterogeneity of the trials. Differences in types of counseling, recommended diets, recommended exercise, meeting types and frequency, settings, baseline characteristics, and other factors produced a wide range of net treatment effects. Although such heterogeneity may enhance the generalizability of our findings, it also complicates efforts to quantitatively and qualitatively combine the studies. Furthermore, studies varied in duration and the time points at which outcomes were reported.

NetSweat.com Comments: Some people do better with the structure and support that counseling provides. The key is to stick with a rationale weight loss program that can be followed over the long-term.