Functional For Life Blog

Breaking Down Fad Diets

“Lose 15 kgs fast”

“The weight-loss shake that doctors don’t want you to know about”  

“The 7-day detox to cleanse your body


Have you ever heard of or tried these types of ‘miracle diets’ that promise to solve all of your health problems and change your life? If so, then you may have encountered a fad diet! Social media is often flooded with these in the beginning of the new year, targeting those whose resolutions are to improve their health.

So, What Exactly is a Fad Diet?

Fad diets are diets with no scientific basis that promise quick fixes to health problems– often promising rapid weight loss. There are a huge number of these types of diets out there, and it can be difficult to spot one!

Fad diets commonly eliminate entire food groups and may often be extremely restrictive1. They often focus on physical appearance, promote unrealistic claims, demonize certain foods, and have a ‘one-size-fits-all’ approach.


While these diets may provide short-term results in weight loss (often due to loss of water weight and muscle), they can lead to deficiencies in important nutrients and cause major health issues. As they have no scientific basis1, they may often include flashy marketing strategies, celebrity endorsements, and ‘success stories’ as promotion to the public. 

As research has continually showed, these types of fad diets are not sustainable, and that the best approach to weight loss is healthy and balanced eating combined with exercise 


Common Fad Diets


Detox Diets/Juice Cleanses


Detox diets and/or juice cleanses promise to flush toxins from your body for weight loss2 and better health- often through very restrictive methods. Some examples of these in recent years are ‘detox’ teas, celery juice cleanses, supplements/herbs, laxatives/enemas, etc. 

Yes, there is evidence that there are environmental substances that can harm human health. 

BUT, the human body is amazing and fully equipped to remove toxins already, with the help of our lungs, kidneys, liver, immune system and gut. There is no evidence that these types of diets eliminate toxic substances from our bodies, and furthermore, they can cause serious health issues and side effects, such as dizziness, weakness, diarrhea, loss of muscle mass, electrolyte imbalances (which can cause major heart problems)3. These types of diets are especially dangerous for pregnant women, the elderly, and people with existing chronic diseases2 (heart disease, diabetes, etc.).


The Alkaline Diet

The alkaline diet basically states that foods we eat can influence our blood pH levels (pH is a measure of the how acidic something is). It proposes that eating too many ‘acid forming’ foods can cause our body to become sick and make us vulnerable to diseases such as cancer, diabetes, etc. The diet suggests that eating ‘alkaline’ foods will neutralize the pH. 


“Acid-forming” foods: meats/seafood/poultry, dairy products, nuts, bread, pasta, rice, alcohol, coffee, sugar


“Alkaline” foods: Most fruits and veggies, almonds, wild rice, sweet potato, quinoa, apple cider vinegar


The problem with the reasoning behind this diet is that the foods we eat do not affect our blood pH! The body works constantly to keep the blood pH at a neutral level, through our urine, saliva, sweat, and breath, making it nearly impossible for us to alter our blood pH through our diet4


While a positive of this diet is that it encourages more fruit and veggie intake, avoiding high-protein foods can cause health problems, as proteins help and maintain muscle, skin, hormones, immunity, etc. Also, while weight loss can happen (due to the low-calorie nature of the diet), the restrictions can lead to many nutrient deficiencies in the long-term4.


The Paleo Diet

The Paleo Diet encourages us to eat the way our ‘hunter and gatherer’ ancestors might have done so many years ago: including foods such as meat, seafood, poultry, fruits and veggies, and nuts, and eliminating foods such as dairy, legumes, grains and processed foods5


While the foods included are nutritious and should be part of a healthy diet6, the avoidance of carbohydrate-rich foods such as legumes, dairy and grains comes with its own set of problems. These foods are an important source of the energy, calcium, B vitamins, protein, and fibre that we need to keep your bodies functioning properly. 


While some small short-term studies may show health benefits of this diet, the large body of quality evidence to date does not support this diet as a healthy and balanced diet. Additionally, excess meat may be cause health problems5. Apart from the health effects of the diet, studies have shown that it is more expensive, makes meal-prepping/planning more difficult, and is difficult to stick to in the long-term5,6.

Final Thoughts

Other diets such as the ketogenic diet and intermittent fasting diets are currently being researched for their effects on human health. While there are some reported benefits in animal studies, there is still a need for good quality and long-term studies in the human population. 

In summary, fad diets are often not based on strong scientific evidence, can be very restrictive, have negative side effects on our health, and are ineffective for sustained weight loss. 

The following recommendations are still the most supported by evidence for the healthy adult population (Australian Dietary Guidelines)7:

  • Enjoy a wide variety of nutrition foods from the 5 food groups 
  • Include different coloured/textured fruits and vegetables (including legumes), lean meats, poultry, fish, eggs, tofu, nuts, seeds, wholegrain and high/fibre cereals, and mostly reduced-fat dairy products such as milk, cheese, and/or their alternatives7 
  • Limit intake of foods containing saturated fat, added salt, added sugars and alcohol7


An Accredited Practising Dietitian can help you further determine what type of eating plan works best for your health goals, body and lifestyle.



Nishaat Patel (Accredited Practising Dietitian)




  1. How to spot a dodgy weight loss diet – Dietitians Association of Australia [Internet]. 2020 [cited 14 January 2020]. Available from:
  2. I’m tired all the time, should I try a detox diet? – Dietitians Association of Australia [Internet]. 2020 [cited 15 January 2020]. Available from:
  3. Information on Cleansing Diets [Internet]. 2020 [cited 15 January 2020]. Available from:
  4. Schwalfenberg G. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?. Journal of Environmental and Public Health. 2012;2012:1-7.
  5. The low-down on Paleo. Dietitians Association of Australia [Internet]. 2020 [cited 14 January 2020]. Available from:




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