Orlistat, an obesity drug, may also be effective when taken at higher doses, researchers found.
More than one third of U.S. adults are obese, and obesity raises the risk of heart disease, type 2 diabetes and some types of cancer. Losing weight - and keeping it off - can reduce those risks.
Long term weight loss through changes in eating and physical activity is possible, even in adults who have already acquired obesity related illness, and effective weight loss programs are now available, researchers led by Stephan Dombrowski of Newcastle University in the UK write.
They pooled data from 45 studies that included a total of 7,788 adults who had lost at least five percent of their body weight. The studies looked at peoples ability to keep the weight off for a minimum of one year.
Forty-two of the studies included an initial phase meant to produce weight loss. The participants in those studies lost an average of about 24 pounds.
The studies all looked at medication or lifestyle changes such as diet, physical activity and meal replacements, either alone or in combination, to help with weight loss maintenance.
The researchers found that people participating in programs that combined diet and exercise gained back 3.4 fewer pounds after one year compared to people receiving no extra help with weight maintenance or standard treatment only.
They also found that combining Orlistat with behavioral changes resulted in 4 fewer pounds regained after one year compared to participants who took a drug-free placebo.
Orlistat appeared to be more effective at larger doses, according to results published in the British medical journal BMJ. But the drug also came with gastrointestinal side effects.
Lori Rosenthal said the findings echo previous research and that it was interesting that the authors included data from so many studies.
Rosenthal is a dietician at Montefiore Medical Center in Bronx, New York. She was not involved in the new review.
I think its great that they covered so many different studies but theres also so much variety and the long-term research isnt there, you know - going beyond 24 months, she told Reuters Health.
Still, We know that interventions like diet and physical activity are really important in preventing weight regain after losing, she said.
Rosenthal noted that participants who had dropped out of the programs were not always included in the findings, and that could affect the reviews results.
Weight management is hard, she said. People have to realize that its not just the losing it - its for life, and if you dont like what youre doing, if it doesnt work for you, youre not going to stick with it.
Support during the weight management phase is important, Rosenthal added. There are support groups and dietitians who can give people tricks and tools to help make it easier, she said.
She offered some advice for people who have lost weight and are moving into a maintenance phase.
Its really important to remember that weight management is a mind and a stomach game, she said. You have to feel good about what youre having.
Really make sure you find foods you like - that youre choosing foods not because youre on a diet but because you like them, Rosenthal said. You have to like them more than the other things you were eating before.
Rosenthal said that if people dont like the new foods they eat or their new routine, they will be more likely to go right back to old habits.
She said being mindful and chewing slowly also allows people to enjoy their food and eat less.