An estimated two-thirds of the population are thinking about, or trying to lose weight at any time. To meet this demand, there is a growing range of commercial and ‘fad’ diets available but, unfortunately, very little research to indicate what works and what doesn’t. This article looks at some of the more popular fad and commercial diets you may be asked about in clinic, giving you the information you need to have a discussion about the pros and cons of different weight loss methods with your patients, to help them lose weight and keep it off. The key finding seems to be – if it sounds too good to be true, it probably is!