fad diet fad diets smoothie

There are lots of reasons for wanting to lose weight or change our diet. However, this should not be at a cost either to your health, your relationship with food or your wallet.

Tempting though the endless range of ‘quick-fix’ and ‘miracle’ options may be, the promises they make for rapid weight loss for minimum effort are often unrealistic and unsustainable. 

Unfortunately, there is no magic solution to weight loss that lasts. There is no such thing as a ‘magic diet’. Most fad diets are associated with some degree of nutritional or health risk. A fad diet is offering a short-term solution to a long-term problem.

What is a fad diet?

A fad diet is a plan that promotes results such as fast weight loss without robust scientific evidence to support its claims. Popular ones include plans where you eat a very restrictive diet with few foods or an unusual combination of foods. They may only allow you to eat certain foods at certain times. Fad diets often consist of expensive and unnecessary food products, ingredients and/or supplements.

Where’s the harm?

Many fad diets will lead to initial weight loss but this weight loss is often lean muscle and fluid loss instead of body fat. Often these diets cannot be followed long term as many people become fed up with the rigid rules and limits. 

When food groups are demonised, and internal cues around hunger and fullness ignored, this can lead to cycles of weight loss followed by weight regain. This cycle can affect our relationship with food, leading to feelings of failure rather than developing the skills and confidence to manage diet and weight in a healthy manner.

How to tell the diet fact from the fiction?

Beware! Stay away from diets that: 

  • promise a magic bullet to lose weight without having to change your lifestyle in any way. These include diet pills, lotions, wearables such as sweat suits 
  • promise rapid weight loss of more than 1kg (2lbs) of body fat a week such as keto or extreme or total fasting
  • recommend magical fat-burning effects of foods such as the grapefruit diet or hidden ingredients in foods (caffeine/coffee diet) or alleged fat burning substances such as green tea extract or raspberry ketones
  • promote the avoidance or severe limitation of a whole food group such as dairy products, all carbohydrates, or a staple food such as wheat. Examples include very low carb/keto (<50g carbohydrate per day unless medically prescribed), carnivore diets or paleo diets
  • suggest substituting everyday foods or food groups for expensive doses of supplements (e.g. IV vitamin drips), expensive ingredients, or special products such as the bulletproof diet or weight loss injections
  • promote eating mainly one type of food (mono diet) e.g. cabbage soup diet, chocolate diet or boiled eggs diet, or avoiding all cooked foods (raw food diet)
  • recommend eating foods only in particular combinations based on your genetic type or blood group (blood group diet)
  • suggest that you are living with overweight because of a food allergy or a yeast infection
  • recommend 'detoxing' or avoiding foods in certain combinations such as fruit with meals
  • are based on claims that we can survive without food or having liquid meals only e.g. water fasting or juice cleanses
  • offer no supporting evidence apart from personal success stories 
  • focus only on your appearance rather than on health benefits with rigid rules
  • are selling you products or supplements
  • recommend eating non-food items such as cotton wool or hydrochloric acid
  • have recommendations based on a single study, testimonials or unrealistic amounts of a food e.g. chilli 
  • recommend the same diet for everyone without accounting for specific needs
  • are based on a ‘secret’ that doctors are yet to discover or ‘don’t want you to know’
  • imply that food can change body chemistry
  • misinterpret medical tests or how the body works such as the alkaline diet, collagen diet
  • are labelled as ‘wellness’ but really are about strictly controlling food e.g. clean eating

Remember, if it sounds too good to be true – it probably is!

Who knows what?

Social media, filters and photoshopped images will have us believe that famous celebrities are picture perfect all the time. However, this is unrealistic and can make us feel bad about ourselves and our own ‘imperfections’. Just because someone is famous does not make them an expert in nutrition.

Many people claim to be experts in nutrition yet have limited knowledge and offer no protection to the public. You should be wary of unqualified practitioners who may be offering unproven techniques to diagnose and treat nutritional problems including:

  • iridology
  • kinesiology
  • craniosacral therapy
  • hair mineral analysis
  • face reading
  • tongue reading
  • colonic irrigation
  • magnetic therapy

Dietitians have recognised qualifications and are regulated. They will be able to guide you through the maze of dietary information that surrounds us and give you safe, unbiased, evidence-based advice. Ask your doctor to refer you to a dietitian or find a freelance dietitian.


  • Fad diets can be tempting as they promise a quick fix to a long-term problem. But restrictive, or extreme diets that have no scientific basis can put your health at risk. 
  • Following a fad diet may cause a cycle of weight loss followed by weight gain.
  • Dietitians will be able to help you know if dietary information is safe and based on evidence.
  • The best way to maintain a healthy weight is to consider your diet as a whole.
  • Make healthier choices where possible and include variety and balance.
  • Listen to your body's hunger and fullness cues.
  • Be aware of portion sizes and consider activity levels.