Founded in the early 1960s, Weight Watchers is one of the most popular worldwide weight loss programs. It has a proven 40-year track record of helping dieters lose weight.

The Weight Watchers program is based on calorie-reduction, using the Weight Watchers points system. No foods are forbidden, although you are restricted to a certain number of daily 'points'.

Most dieters follow the Weight Watchers program by joining a weekly class, where they meet other dieters, exchange ideas and receive support and advice from the class organizer. Weight Watchers also provides an online at-home program.

The Weight Watchers program does not offer fast weight loss, but it's predicted average weight loss of about 2 pounds a week is the accepted maximum. For many dieters, Weight Watchers is a very useful starting point. It provides enormous support and a lot of sound advice.

At between $10 and $15 a class, plus a joining fee, the cost can mount up. In the USA, class membership may lapse after 4 missed classes, so check the details before you start. Weight Watchers Online program starts at about $44 for a standard monthly plan.

Overall verdict - An excellent and proven diet program.