A recent study published in the October 12 issue of The New England Journal of Medicine examined people who had lost an average of 42 pounds. After the initial weight-loss, these people were followed for another 18 months. the researchers were looking for the best way to maintain the weight loss. Monthly face-to-face- follow up visits with a clinician (in this case a psychologist and a group) and daily weighing, on average resulted in a 5 lb. (2.5 kg  ± 6.7 kg) weight gain after 18 months in the program. Meeting monthly with a clinician over the internet was not quite as good. Both of these methods, however, were significantly superior to getting a monthly newsletter about weight loss and nutrition.

http://www.medscape.com/viewarticle/545923?src=mp