What is a fad diet?

Fad Diets: What is it? And are they healthy?

A quick Google search with the phrase ‘what is a fad?’ and I am inundated with multiple fad diet examples. Ever heard of the Werewolf diet? I definitely haven’t so that one is news to me.

This article summarises what a fad diet is, how to spot one and the pros and cons of some of the most popular fad diets.

Nutrition Bite: A fad diet is a way of eating the typically takes away or avoids one of the 5 food groups, it’s restrictive, hard to follow in the long-term and is often associated with a specific product or celebrity endorsement. Some Fad diets can promote an increase in the amount of fruit and veg which is a good thing however their reason for doing so is not always backed up by evidence and can be supported by outlanderish claims - this makes people confused about nutrition science and who to trust. 
— Be Well Fed dietitian

What is a fad diet?

A fad is described as an extreme and intense enthusiasm for something – a craze of sorts.

When we look at a fad diet, typically they make promises of quick weight loss or promote the attainment of a specific health advantage if you stick to the diet.

Common themes of a fad diet include:

  • A lack of scientific evidence to back up the claims
  • Restrictive
  • Eliminate a whole food group
  • Expensive and can promote the use of a specific product or food
  • Promote a one size fits all eating pattern

How to spot a FAD?

It can be difficult to spot a fad because there are many people dabbling in nutrition either as a hobby or as a career. Some of which are not qualified.

To spot a fad ask yourself the following questions:

  • Is it endorsed by a celebrity? Or associated with a celebrity?
  • Is it associated with a product or specific food?
  • Does it offer me something that seems too good to be true like a quick fix?
  • Is this supposedly new way of eating or diet suited to my lifestyle? Is it reasonable to think I can follow it?
  • Does it limit or restrict a particular food or food groups I enjoy?
  • Are all five food groups included in the fad?  That’s 1) grains and cereals, 2) dairy and alternatives, 3) meat, legumes and alternatives, 4) vegetables, 5) fruit.

If not, it’s likely the creators have eliminated at least one of these food groups and it is a fad plus those that endorse it are likely to be getting a cut and are unqualified to give nutrition advice.

Is a fad diet healthy?

There are some fad diets that may seem healthy initially but if the way of eating restricts or eliminates a specific food group in one-way or another the chances are it is not healthy.

The Australian Guide to Healthy Eating is inclusive of 5 food groups for a reason. Each of the 5 food groups is a source of specific nutrients required for our bodies to function at an optimum level.

For example:

Fruit and Vegetables are essential as they are high in a range of different fibres, anti-oxidants and phytonutrients.

Let's take a look at some of the most popular Fads:

Juice Cleanse

A juice clean involves consuming fruit and something vegetable juices for a period of weeks or days. 

People seem to state they feel so much better after they have done a juice cleanse but have you ever seen someone actively doing the cleanse itself. Honestly, they look like s**t – so of course, they are going to feel like a million bucks as soon as they start eating normally again.

Although juice might seem like a great idea to gorge in, just 125ml of fruit juice is classified as a serve of fruit (we only need 2 serves a day). Juice eliminates the fibre from the fruit - an essential nutrient required to help keep us regular, maintains bowel health and keeps us fuller for longer.

Pro: Drinking juice with no added sugar tastes great and can help you reach the recommended 2 serves of fruit per day. 

Con: No fibre, cuts out most of the food groups including protein sources and healthy fats. This can result in increased risk of metabolic syndrome, liver damage and obesity in the long run.



Vegan diets a restrictive way of eating that excludes all animal products. This includes the exclusion of key nutrients including B12, protein, iron and vitamin D.

When used for weight loss, veganism can be considered a FAD diet. These days many people are choosing to follow a vegan diet in order to be environmentally friendly, human and ethical and that’s ok but without careful planning to ensure all nutrients are included takes time (and money).

Here are some of the nutrients vegans typically miss out on and need to make sure they are getting enough of:

  • B12 is mostly found in animal products but you can get it from algae and some mushrooms.
  • Protein is essential for bone and muscle structure and the immune system. Ensuring vegans get adequate protein from plant based sources including beans, tofu, lentils, and quinoa is essential.
  • Iron can be found in green plant-based foods such as spinach and kale but this is a different type of iron compared to what is found in meat products.

Pro: If done right includes a lot of fruit, vegetables and legumes.

Con: Often miss out on key nutrients including B12, protein, iron and vitamin D, and it's time consuming to plan a nutritionally adequate vegan diet.

Alkaline diet:

This diet decreases the amount of so-called acid-producing foods people eat. This includes meat, grains, refined sugar, dairy, caffeine, alcohol and processed foods in favour for alkaline foods. There’s lots of veg and fruit and not much protein.

The theory goes that reducing acid foods reduces inflammatory conditions such as osteoporosis and arthritis and helps you loose fat.

This diet and the mechanism behind it isn’t backed by scientific evidence or the way the human body works. The body regulates its own blood pH between an extremely narrow range of 7.35 and 7.45 and we would simply not survive outside of these parameters.

Pro: Includes more fruit, vegetables and grains and eliminates refined sugars, alcohol and processed foods.

Con: Not much protein is included. Does not reduce inflammatory conditions and stretches the truth when discussing how foods affect the bodies blood pH.

Paleo Diet:

Also called the Stone Age or the Palaeolithic diet, its focus is on eating the foods our ancestors ate in the hunger and gather era. These foods typically require little or no processing before being consumed.

The Paleo diet is based on the theory that that our digestive systems stopped evolving 10,000 years ago. According to this, a the current modern diet would then be detrimental to human civilisation and cause disease.

Foods allowed on a paleo diet include: meat, poultry, seafood, fruit, vegetables and nuts. Packaged foods, dairy, legumes and grains are off the menu (see below).

 Ad libitum = 'at your pleasure'

Ad libitum = 'at your pleasure'

Grains are a great source of folate and fibre amongst other nutrients, required for DNA regeneration and maintaining bowel health. Plus fibre helps to reduce cholesterol.

Excluding dairy is a big no, no. Dairy is a source of protein, B12, calcium and vitamin D. One study found that participants on a 3 week Paleo diet only consumed 50% of the recommended amount of calcium. A lack of calcium in the diet could leave to osteoporosis later in life. 

Pro: Includes nuts and seeds that are a source of healthy fats. Encourages lean meat and lots of vegetables and fruit.

Con: Excludes grains, legumes and dairy.


The raw food diet:

This diet focuses on eating unprocessed plant-based foods in a raw state. The raw state is thought to retain enzymes and vitamins that can be destroyed through cooking at temperatures above 40°C.

Although we do get some nutrient losses in cooking including vitamin C and folate, humans have been cooking for thousands of years and our digestive system has adapted to this.

In fact, eating some food raw including unpasturised (means heating of the milk to kill bacteria) dairy and some meat may increase the risk of food-borne infections as a result of the bacteria found on the food. 

Pro: Promotes the consumption of more veg and fruit.

Con: Raw foods can be harder to digest and some minerals cannot be absorbed. There is a risk of bacterial contamination when eating raw meats and eggs. It is also time-consuming to prepare.


What is the best fad diet?

The best fad diet is the one you can follow long-term, is individualised, includes all food groups, doesn’t restrict food and is backed by scientific evidence.

 There is no fad diet that is best.  



FAD diets are required to be healthy. Although some fad diets promote an increase in fruit and veg which is a good thing, overall the exclusion of specific food groups such as dairy, grains and legumes in the paleo diet,  protein in the alkaline diet, and animal-based foods in a vegan diet can be harmful in the long run. 

Instead of FAD dieting, learn how to cook quick and easy meals that benefit you as an individual. Book a cooking consult with Be Well Fed to learn foods and way of eating is suited to you and your lifestyle – all the things a fad diet just won’t be able to achieve.