what are fad diets

The Truth About Fad Diets in 2021

We’ve all seen the advertisements for the so-called miracle or fad diets promising rapid weight loss results in a short period, usually requesting money in exchange for a plan and their secrets.

But what exactly is a Fad diet? Are they effective for weight loss? Are they dangerous for our health?

As weight-loss experts here at Plato Weight Management, it is our job to know about and advise our clients on these diets due to their exposure that they receive on social media.

Therefore, in this post, we will break down:

  • What is a fad diet
  • Types of fad diets
  • Fad diet plan example
  • Why fad diets produce deceptively fast weight loss
  • Dangers of fad diets
  • What types of diets work?
  • Tips for eating healthier
  • Fad supplements

What is a Fad diet

what are fad diets

A Fad is defined as “an intense and widely shared enthusiasm for something, especially one that is short-lived; a craze”.

So a Fad diet is a diet that makes promises concerning its speed and ease of weight loss, lacks evidence in support of the diet, and has questions surrounding its effectiveness and safety.

Hankey and Wheelan (2018) list red flags to watch out for to know whether a diet is a fad diet:

  • The promise of rapid weight loss, usually above 1 kg (2 lb) per week
  • Restricts a large number of foods and/or whole food groups
  • Recommends consumption of large amounts of one food or food type
  • Suggest foods that should be eaten in a specific order or specific combination
  • Suggests that certain foods or ingredients “burn fat”
  • Is nutritionally imbalanced
  • It does not include or encourage exercise
  • Based on anecdotal evidence and/or testimonials rather than robust clinical trials and/or simplistic conclusions drawn from complex studies
  • Makes dramatic claims not supported by evidence or seem “too good to be true”
  • Requires purchase of specific products, supplements or resources
  • Provides no health warning to those with pre-existing medical conditions
  • Focus on appearance-related outcomes rather than health benefits

Types of Fad diets

Now is it debatable whether several popular diets may fall into the fad diet category. For instance, diets like The Dukan Diet, Paleo, Keto, Vegan, South Beach and the Atkins diet may be considered fad diets, but each does have evidence showing effective weight loss.

For instance, the Atkins diet, the Dukan Diet and the South Beach diet are essentially low-carb diets, and low-carb diets have been shown to be one of the most effective dietary regimes for weight loss.

Therefore, in this blog post, we will not be promoting or downgrading any of these diets. Our focus is on the diets with no meriting behind at all.

Types of fad diets are:

  • Military 3 Day Diet
  • The 7-day Cabbage Soup Diet
  • Acai Berry Diet
  • Apple Cider Vinegar Diet
  • Blood Type Diet
  • Grapefruit Diet
  • HCG Diet
  • Liquid Diet / Juice Cleanse
  • Negative Calorie Diet

Fad diet plan example

One example, which you may have heard of, is the 7-day cabbage soup diet. A standard plan of this diet may be as follows:

what are fad diets

Day 1: Eat only fruits except for bananas.

Day 2: Start the day with a baked potato. Then eat only vegetables except for corn and other starchy vegetables.

Day 3: Eat only fruits and vegetables except for bananas and starchy vegetables.

Day 4: Eat only bananas, milk and yoghurt.

Day 5: Eat only tomatoes and protein like fish, chicken or turkey.

Day 6: Eat only protein and veggies (no starchy vegetables).

Day 7: Eat only fruits, vegetables, and juices (no bananas or starchy vegetables)

Daily: Eat as much cabbage soup as you’d like. Drink eight glasses of water every day

Why fad diets produce deceptively fast weight loss

Let’s break down why this diet may provide accelerated weight loss results over one week.

Well, the first reason is that most of the weight loss experienced is water.

In a normal diet, carb-containing foods that we eat are broken down to glucose in our bodies, giving the cells within our body the energy they need. And when our cells receive sufficient glucose to work effectively, the rest of the glucose is turned into glycogen and stored in our liver and muscles to be used as quick energy later.

This is relevant as water binds to glycogen and for every gram of glycogen stored, up to four grams of water are stored with it.

Therefore, when glycogen levels fall in response to the cabbage soup diet due to the minimal intake of carbs, so does our water weight. This means that you would regain all of the water weight back from the refilling of the glycogen stores when you stop this overly restrictive diet and return to your previous carbohydrate intake levels. So this really is only temporary weight loss.

The second way that weight loss occurs is through the caloric restriction involved, which would indeed contribute to weight loss via the reduction of fat stores rather than water weight.

So that’s ideal, right?

Well, not exactly, as the calorie restriction will be too low as we need to consume at least 1400 calories daily in order to intake enough vitamins and minerals for our health.

What’s more, due to compensatory mechanisms in our body, we will start to crave higher-calorie foods more often after the period of excessive calorie restriction brought about by the cabbage soup diet, subsequently replacing the fat lost eventually. 

Calorie restriction can also contribute to weight regain because it lowers the calories you burn through your metabolism daily, which accounts for up to 60% of the calories we burn each day from pumping blood around our bodies, breathing, processing nutrients and producing cells.

One study found that low-calorie diets can decrease the number of calories the body expends by up to a quarter which can happen for a long time after the overly restrictive diet has ceased. 

This slowing of the metabolism may be caused by muscle loss due to the inadequate protein intake to support muscle maintenance from the overly limited diet.

fad diets

Further, excessive calorie restriction will result in you feeling very hungry and grumpy throughout the day. Although it may limit the calories going into your body, it will simultaneously reduce your energy even to perform daily physical tasks like errands or chores, let alone exercise to improve your health.

Furthermore, although weight loss is the primary motive for dieters, weight maintenance after that is equally as important.

If a diet we undertake is not focusing on implementing long-term sustainable eating patterns, it will not break the yo-yo dieting cycle, which is detrimental to our health further.

You may apply the principles of why the cabbage soup diet is not practical for weight loss can be applied to any fad diet also.

The read our blog about the alkaline diet, please follow the link here.

Dangers of fad diets

Further dangers of fad diets are:

The minimal calorie intake associated with the diet can weaker your immune system and make you more susceptible to becoming sick, especially if you are undertaking vigorous exercise frequently or working a strenuous job (Hagmar, Hirschberg, Berglund, & Berglund, 2008).

One study demonstrated that athletes who undertook a calorie-restrictive diet to lose weight just a week before the competition had a higher likelihood of infection (Tsai, Chou, Chang, & Fang, 2009).

It may decrease your bone mass density as too few calories can reduce hormones like testosterone and estrogen that support healthy bones (Loucks, 2004).

Also, a minimal intake of calories enhances your stress hormones in your blood, which has also been suggested to reduce bone density (Fuqua & Rogol, 2013).

Therefore, excessive calorie restriction periods may increase your risk of fractures.

What types of diets work?

what are fad diets

To find a suitable diet to achieve effective weight loss, an important thing to do is to honestly ask yourself if you can consistently follow this diet plan long term and intake adequate amounts of protein, vitamins and minerals in the process.

If you can, then the diet of choice is most likely an effective approach. If you can’t, then it is most likely a fad diet.

Additionally, it’s unlikely that you won’t eat sweets or chocolate ever again, so any fad diet that wants to eliminate these foods or others altogether is not a good or realistic aim.

When looking to reduce weight while improving your health, make sure to contact a nutrition professional, which you may contact us about here about.

Weight reduction of around 0.5-1 kg (1-2 lbs) each week is a healthy and realistic weight loss target over the long-term.

Tips for eating healthier

Here are some extra tips to help you with eating a more healthy diet: 

  • Make an extra effort to eat fruits and vegetables as both food groups are essential for health.
  • Opt for whole grains over refined cereals and bread.
  • Reduce your intake of sugary drinks and increase your water consumption.
  • Consume lean meats, poultry, and fish, while making sure that you keep portion sizes in check.
  • Intake adequate amounts of calcium by consuming low-fat dairy products and calcium-fortified foods.
  • Breakfast should be part of your everyday routine, as those who do are more likely to have a healthy BMI due to the filling effects of the fibre to avoid snacking unnecessarily throughout the day.
  • Monitor your food intake with a food diary initially for the first several weeks until eating nutritious foods becomes second nature.

Fad supplements

Unfortunately, it is not just fad diets that we need to be mindful of but also fad supplements.

Here at Plato Physio, we advise you to always proceed with caution regarding supplements and only use them if you have gotten the go-ahead from your doctor and been given the correct intake quantity.

It’s also noteworthy that many minerals work in antagonistic pairs, which means that you could be taking one type, which may be decreasing your quantity of another type.

Moreover, by supplementing excessively, it’s possible that it could cause toxicity, although that can’t occur from a well-balanced diet instead.

Guys, if you are healthy, you have only a small chance of having a vitamin or mineral deficiency if you make sure your diet is including all of the necessary food groups. Ultimately, obtaining different micronutrients from a good diet is more important than spending your well-earned money on supplements.

To read our blog about if Intermittent fasting is effective for weight loss, please follow the link here.


To summarize, fad diets will always be sought-after, and new plans will be developed to meet people’s ambition to reduce weight rapidly.

On the other hand, even though most fad diets are unbalanced, unhealthy, and fail to deliver on their promises, few are incorrectly categorized as fad diets that do.

However, despite a diet being effective at short-term weight loss, it does not imply that it is effective for long-term weight loss and weight maintenance.

To obtain and keep your weight-loss hopes, you must find a healthy eating plan that you enjoy and can stick to.

If you are interested in undertaking one of our evidence-based and results-backed Plato Weight Management programs, please make sure to check what program may be suitable for you at this link or contact us here!

You can find out what some of our previous clients had to say about the program on our success stories page!


Rosenbaum, M., & Leibel, R. L. (2010). Adaptive thermogenesis in humans. International Journal of Obesity, 34(S1). doi:10.1038/ijo.2010.184

Hagmar, M., Hirschberg, A. L., Berglund, L., & Berglund, B. (2008). Special attention to the weight-control strategies employed by olympic athletes striving for leanness is required. Clinical Journal of Sport Medicine, 18(1), 5-9. doi:10.1097/jsm.0b013e31804c77bd

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