Recent research from the US has found that individuals who maintain contact with a weight loss professional are more likely to keep more weight off.

The weight loss industry is a huge one, but one which is often unable to provide evidence of longer term success.

Contact with interactive dieting websites was also found to be beneficial, but only for a limited time. After two years of online contact the benefits were found to wane.

Study lead author Dr Laura Svetkey, a professor of medicine at Duke University Medical Center, said, ‘Two and a half years after weight loss, the personal contact group had gained less weight. The difference was only 3.3 pounds [between the personal contact group and the interactive technology group], but even small amounts of weight loss can improve health’.

Nearly 1,700 obese or overweight participants took part in the study, all of them also suffering from either high cholesterol, high blood pressure or both. More than a third of participants were male and nearly 40 per cent were black, factors which Svetkey highlighted because blacks and men tend to be underrepresented in weight-loss studies.

In the six-month weight loss program which formed the first phase of the study, dieters met weekly for group-based behavioural intervention treatment. Their goals were a reduced intake of calories, sensible approach to diet and three hours of exercise each week with the aim of losing one to two pounds per week. At the end of this phase the average weight loss was nearly 19 pounds (8.6kg).

Phase two of the study saw participants being assigned randomly to one of three ‘maintenance’ groups - the personal contact group, the interactive technology group, and the self-directed group. Those in the personal contact group were contacted monthly by a counsellor (three times in person and nine times by phone). Those in the interactive technology group were given unlimited access to a custom-made weight-loss Web site and the self-directed group was urged to maintain their weight loss but received no further intervention.

Thirty months later, the group with personal contact had regained some weight, but an average of 8.8 pounds (4kg) less than the self-directed group. The interactive technology group also displayed weight regain, an average 3.3 pounds (1.5kg) more than that regained by the personal contact group.

Evaluating the findings, Svetkey said, ‘I think that the tools we used in the weight loss phase and then tried to reinforce in the maintenance phase may have been easier to reinforce in an in-person setting. There’s something about human contact that seems to make a big difference’.

Medical director of St John Weight Loss Institute in Michigan, Dr Kelly Machesky commented, ‘I believe the crux of [the personal contact group's success] has to do with someone else taking an interest in seeing the outcome. Change is possible. Truly, you can make a difference with simply reducing caloric intake and increasing energy expenditure’.