We all find it difficult to meet our weight loss resolutions, and now a new study has made it official that it is indeed tough to shed those extra kilos.

New studies by McMaster University researchers reviewed hundreds of recent studies published in the past decade about the prevention and treatment of overweight and obesity among children, among adults and about keeping lost weight off.

There were small improvements in weight outcomes. The programs that work best targeted school-aged children and youth, were delivered in educational settings, included both diet and exercise and lasted 12 weeks to a year.
Regarding treating overweight/obesity among children and youth, a review of 31 studies found: Evidence showed that enrolment in a program that focuses on changes in diet, exercise and lifestyle can help reduce weight and, more importantly, enrolment in such a program also improves health and quality of life in children and adolescents. However, the permanence of this weight loss has not been well studied.

Almost no trials have been conducted to investigate programs that help normal-weight adults maintain their normal weight. A single small study conducted in the U.S. in the 1980s showed benefits from a 12-month education and incentive-based program.

Doing some activity is better than doing nothing. Adults who took part in some form of treatment had, on aver age, a three kilogram (or seven pound) greater weight loss than adults who did not.