Stay one step ahead of the fraudsters with our series of articles giving you the lowdown on the scams they use to trick people out of their hard-earned cash - and how to avoid being taken in by them.
This week, weight loss fraud, which is often - but not always - aimed at women and generally involves the sale of pills or potions that only help you lose pounds in a financial sense.
Whether you're flipping through a magazine, scanning your emails or watching television, you will often see adverts for products designed to help you lose weight.
Some of these - for example exercise machines and diet cook books - can help you to shed those excess pounds.
But many of the "miracle" products sold to help people slim have no positive effects at all.
That's why American weight loss guru Kevin Trudeau was recently sentenced to 10 years in prison for conning consumers into buying his weight loss books, and why messaging service Snapchat has cracked down on hackers spreading weight loss ads among its users.
Common scams include those involving metabolism-boosting pills, fat or carbohydrate blocking pills, herbal weight loss teas, diet patches and body wraps - some of which can be very dangerous for your health.
How can I avoid being caught out?
As with many scams, the key here is to avoid any weight loss schemes that seem to good to be true.
If, for example, the ad claims that you can lose a stone in two weeks, it is almost certainly a scam - and probably bad for your health if it does work.
In fact, if you really want to lose weight, your GP is probably the best person to ask.
I've been defrauded. What should I do?
You are unlikely to get your money back if you buy a weight loss product that does not work - although you may be able to take advantage of the "guarantees" offered by certain companies if you return the product within a certain time.
Either way, it is worth reporting the crime to Action Fraud (0300 123 2040) so that it can take action against the criminals behind the scam if appropriate.