Shedding the extra kilos is difficult and keeping it off over years is even harder, but a team of researchers has found one group that has defied the trend of regaining weight.

The research from the University of Colorado Anschutz Medical Campus demonstrated the effectiveness of long-term participation in a national weight-loss program.

The investigators followed over 65,000 overweight or obese people who joined Take Off Pounds Sensibly (TOPS) between 2005 to 2010. In the first year, half of participants in the nonprofit weight-loss support group had significant weight loss.

Of the patients with significant weight loss in the first year who participated in a second year, 80 percent kept off the weight. Each year, during years three to seven, roughly 90 percent of patients who continued participation in the program maintained their weight loss.

The researchers concluded that after one year of significant weight loss, consistent participation in the program helped participants sustain their new healthy weight.

"Maintaining long-term weight loss is a critical challenge in treating obesity and related health problems such as diabetes, high blood pressure and heart disease," said lead author Nia S. Mitchell, adding "Just losing the weight isn't enough. Since the health benefits of weight loss disappear when weight creeps back on, we need more research into effective strategies for maintaining a healthier weight once it is reached."

Mitchell concluded that further studies of the TOPS program should examine which populations will succeed at weight loss and weight-loss maintenance and determine factors that can improve sustainable weight loss and maintenance.