Dieting can be very bad for your health. Celebrities promote themselves and help make the diet companies millions by endorsing sometimes ludicrous regimes in magazines. The articles are massively read by people who yearn to lose weight. Yet very few diets have any evidence of effectiveness after the first 12 weeks at best, when the pounds always fall off because you are eating less. But if this is quick-fix rather than long-term sustainable change in your eating and lifestyle habits, it all goes back on again - and then some, as I detailed in my book.
So it's great to hear a collection of young scientists from the organisation Sense About Science trying to debunk fad diets. They have done it by making some up - it's not hard - and intermingling the fake with some of the bestsellers. Can you tell the difference? It's not as easy as you might imagine. Take their quiz here.
These are some of the clues that may indicate questionable diet marketing, they say:
Immune boosting. You can't and you don't need to.
Detox. It's a marketing myth - our body does it without pricey potions and detox diets.
Superfood. There is no such thing, just foods that are high in some nutrients.
Cleansing. You shouldn't be trying to cleanse anything other than your skin or hair.
This is the advice of Leah Fitzsimmons, a biochemist and member of the Voice of Young Scientists:
Never mind about being tempted by that slice of cake - don't be tempted by fad diets. When you see extraordinary claims, always ask for evidence.
And this is the comment of Catherine Collins from the British Dietetic Association:
Let's be realistic about fad diets - they don't work. They don't accelerate weight loss because they're not sustainable long term. If you plan to lose weight you need to recognise you're committing to a marathon, not a sprint. They don't improve your health, nor act as a talisman to protect you against cancer, Alzheimer's, or whatever health risk is the media focus du jour. Fad diet promoters never let sound nutrition get in the way of persuasive marketing to the public, but rely on the publics' lack of knowledge on diet and health to promote their dietary myths and generate financial profit.
Quite. Real, lasting weightloss - which importantly brings about better health as well as a slimmer shape - means changing not only what you eat, but how and why you eat and what you do and how you feel about your life. Possible - oh yes. Quick and simple - no.
'It is the boom and bust economics of dieting that takes the worst toll on health.' Photograph: Johanna Parkin for the Guardian