Diet changes, exercise and other behavioural tactics do help obese adults shed some kilograms – with or without the help of medication, according to a study.
In the new review, of 58 clinical trials, researchers found that behavioural programmes helped obese people lose an average of 3.175kg more over 12 to 18 months, versus people who received no special therapy – most of whom lost little to no weight.
And the more intensive the programme, the better, said lead researcher Dr Erin S. LeBlanc of the Centre for Health Research at Kaiser Permanente in Portland, Oregon.
On average, people who had 12 to 26 sessions in a comprehensive weight-loss programme over one year lost 4 to 6.8kg.
One-third of US adults obese
Comprehensive meant that a programme offered a range of tactics – such as exercise sessions, goal-setting and overcoming day-to-day barriers to keeping up a healthy lifestyle.
And adding medication seemed to boost weight loss a bit, LeBlanc's team found.
It's estimated that one-third of US adults are obese, and cutting those excess kilos is notoriously difficult.
In trials that tested intensive behavioural therapy plus the weight-loss drug orlistat (Xenical), people lost an average of 5 to 9.9kg, versus 3.17 to 5.8kg with behavioural therapy alone.
Adults screened for obesity
The review, reported in the Annals of Internal Medicine, was done to help the US Preventive Services Task Force (USPSTF) update its recommendations on obesity screening and treatment.
In 2003, the USPSTF – a federally supported panel of medical experts – recommended that all adults be screened for obesity, with a simple calculation of weight in relation to height.
It also said that intensive behavioural therapy, like programmes combining nutrition education and exercise, was an effective obesity treatment.
It's not clear if the USPSTF will now alter those recommendations at all. The panel is scheduled to publish a draft report of its updated advice online. The Agency for Healthcare Research and Quality, a federal agency that supports the task force, could not say when the recommendations will appear.
Medication has side effects
For now, LeBlanc said, "the take-home message is that behavioural interventions do work for weight loss. And if you attend sessions more often, you lose more weight."
The extra weight loss with medication, meanwhile, would have to be balanced against the risks: side effects of Xenical include gas and uncontrolled bowel movements, and the drug has been linked to reports of liver, kidney and pancreas damage.
There are also important questions about the ultimate benefits of behavioural therapy, according to LeBlanc. Studies have not yet shown whether the weight loss won with behaviour changes actually prevents major diseases like heart disease – or prolongs people's lives.
A couple trials have, however, suggested that the programmes help curb the risk of diabetes in obese people with elevated blood sugar levels, LeBlanc said.
The problem, she explained, is that studies have to be large and go on for many years before the effects on heart disease and death can be pinned down.
As for obesity screening, the researchers found no trials that have been specifically set up to weigh the benefits against any potential risks.
Measuring someone's weight and height carries no direct harms. But, LeBlanc's team notes, there are theoretical risks to screening for obesity – like whether labelling someone as obese creates stigma or, more practically, higher insurance premiums.
The 2003 USPSTF recommendations do call for obesity screening, based on the fact that it can be safely and reliably measured, and there are effective, low-risk behavioural therapies.
Finding those effective therapies is another matter. Comprehensive weight-loss programmes, LeBlanc noted, would be difficult to do in the primary care setting. "The question is, how do you make these widely available to people?"
There may be programmes in your local community, and as a starting point you can ask your doctor for recommendations, LeBlanc said. The costs of behavioural approaches would vary, and you may well have to foot the bill yourself, depending on your insurance coverage.
The current review did not look at the cost-effectiveness of obesity screening or the behavioural therapies for it.
(Reuters Health, October 2011)