10 Reasons to Avoid Fad Diets

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With an increasing media focus on ‘miracle’ weight loss solutions it can feel as if we are being bombarded with fad diets. If it’s not restricting your diet to just grapefruit, tea, juice or baby food; it’s the promotion of ‘superfoods’, ‘clean eating’ or saturating your life in coconut oil (pun intended for my fellow nutrition geeks!).

Fad diets offer big results with minimal effort; but in reality they can often cause much more harm than good. You can also check out my Nutritional Nonsense Detection Kit to learn how to spot and avoid these fads.

1. Fad diets lie!

The simple fact that fad diets are not evidence based is the reason that they are called a “fad” at all, otherwise they would likely be featuring on Eatwell plates and Food Pyramids. For example there have been many dramatic health claims made about coconut oil, including: improving cholesterol levels, increasing metabolism, relieving kidney problems, heart disease, diabetes, HIV, cancer and Alzheimer’s disease. But these claims are very misleading as they haven’t been backed up by good scientific data, and in fact possible negative effects on cholesterol have been found1,2.

2. Fad diets could slow our metabolism

Because of our built in mechanism called homeostasis which keeps our bodily systems stable, our metabolism may sow down to conserve fuel when we are deprived of food; especially if somebody is losing muscle mass. Basically this means that although somebody might suddenly lose weight from an extreme fad diet, it often becomes more difficult to lose weight in the long term and can result in more weight gain than the original weight loss. However the research into this is slightly conflicting, see my post ‘Can Losing Weight Lower Our Metabolism?‘ if you want to find out more about this.

3. Fad diets are unbalanced

As most fad diets promote cutting out whole food groups this can lead to nutritional deficiencies. For example with alkaline diets which promote excluding most food except for fruit, vegetables, pulses and nuts this will lead to greatly reduce intakes of: iron, calcium, protein, healthy fats and whole grains (which are a great source of fibre, slow released energy and B vitamins) which could lead to problems such as anaemia, osteoporosis and bowel issues to name but a few.
Certain diets also cause nutritional excesses, for example juice diets are very in high sugar but low in: slow released energy, fibre, protein, fat, iron, and calcium. Similarly, low carbohydrate diets are often high in saturated fat as butter and red meat are unrestricted but fruit and grains are not allowed; and a high saturated fat intake can greatly increase cholesterol levels and the risk of heart disease4.

4. Fad diets are not personalised

Fad diets often promote a “one fits all” approach which doesn’t take into account a person’s medical situation, psychological state or their financial position. For example if a person on diabetic medication started an unsupervised fasting diet this could lead to dangerously low blood sugar levels which could potentially lead to a diabetic coma.

5. Fad diets are unsustainable

As most fad diets are very restrictive it is unrealistic to maintain these for the rest of your life, and when slip ups occur this can lead to bingeing and comfort eating as a response to such restriction. I know if I had somehow managed to survive off carrot juice for a week, I would eat everything within a mile radius of me the moment I broke the restriction! Similarly fasting diets promote an “all or nothing” approach which can lead to cycles of purging and bingeing resulting in unbalanced eating habits in the long run.

6. Fad diets promote obsessive food behaviour

Due to their often extreme and restrictive nature, fad diets can create an overall unhealthy relationship with food causing people to “food shame” and associate excess guilt with dietary slips ups. Fad diets can also potentially mask or create eating disorders depending on the level of obsession involved. There has been more attention recently into “orthorexia nervosa” which is an obsession or fixation with healthy eating; this isn’t currently recognised as an eating disorder but it displays many similar characteristics5.

7. Fad diets can be socially isolating

Apart from being an essential part of health and survival, eating and drinking are an important part of socializing for most people. So if you can only eat on certain days, or very specific foods or in specific combination this can make going for dinner with friends or eating lunch with work colleagues a lot more difficult and may lead to feeling alienated and isolated.

8. Fad diets can cost a bomb

Most fad diets ask for website subscriptions or promote buying specific books. Many also make a lot of money from selling products; one specific website I found was selling supplements for $10 – $80 (roughly £7 -£53) each and was also selling water kiosks related to the diet for $750 – $3000 (roughly £495 – £1978). Diets which provide specific prepared meals and products can also add an unnecessary monthly cost when compared to homemade healthy meals.

9. Fad diets can be dangerous

As mentioned above fad diets can cause a number of health problems such as: nutritional deficiencies, nutritional excesses, interacting with medical conditions, creation of eating disorders and feelings of social isolation. Other dangers include promoting fad diets to replace medical treatments, such as the alkaline diet which is often promoted as being a holistic alternative to established medical treatments for cancer, even though there is no good evidence to support this and it can lead to devastating effects for the individuals involved6. Some of the so called “detox cleanses” which promote taking large amounts of vitamin supplements can ironically have a toxic effect on the liver. Also, detoxes often include severe fasting which can lead to weakness, dizziness, dehydration and irritability7.

10. Fad diets are unnecessary!

One of the most important points is that fad diets are not necessary; the best evidence that we have so far in relation to diet and health shows that adopting a Mediterranean style diet can have a protective effect on: obesity risk, heart disease risk, diabetes risk and from certain kinds of cancer8. This means having regular meals, plenty of fruit, vegetables, beans and pulses, whole grains, fish and using olive or rapeseed oil instead of other fats. It is also important to avoid taking in too much sugar, fat, salt or calories, keep portion sizes modest and to be physically active. Unfortunately there is no quick fix, but maintaining a healthy balanced diet including foods from each food group as well as allowing yourself to have treats in moderation will result in a much healthier and more enjoyable relationship with food and will promote much better health outcomes in the long run, so let’s ditch the fad diets!

Updated 04/06/17


1. http://daa.asn.au/for-the-public/smart-eating-for-you/nutrition-a-z/coconut-oil/
2. http://scepticalnutritionist.com.au/?p=844
3. http://www.nhs.uk/livewell/loseweight/pages/how-can-i-speed-up-my-metabolism.aspx
4. https://www.nice.org.uk/guidance/ph25/evidence/ph25-prevention-of-cardiovascular-disease-expert-papers-10-saturated-and-unsaturated-fats2
5. https://www.nationaleatingdisorders.org/orthorexia-nervosa
6. http://skepdic.com/alkalinediet.html
7. https://www.bda.uk.com/foodfacts/detoxdiets.pdf
8. https://www.nice.org.uk/news/press-and-media/a-healthier-diet-and-being-more-active-is-important-for-everyone-not-just-if-you-are-overweight
9. https://www.bda.uk.com/foodfacts/faddiets.pdf


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Founder of The Food Medic

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Maeve has written extensively for NHD magazine over the last few years, producing a wealth of dietetic and nutritional articles. Always evidence based and factual, Maeve creates material that is relevant and very readable. She provides high quality work with a professional and friendly approach. Maeve is a beacon of high quality knowledge and work within the nutrition writing community; and someone NHD magazine is proud to work with.

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