Fad Diets: Types, Risks, and Tips

fad diets that work

From the Atkins diet to Slimming World, fad diets are an ever-evolving trend constantly seen in some capacity in the media and online. They purport huge weight-loss claims, often without evidence or scientific backing, but when they say all the right things it can be hard to determine the truth about fad diets and their effectiveness.

We’ve done the research and figured out the fad diets that work and the ones to avoid so you can change your diet in a healthy way.

In this article we’ll be giving an extensive list and overview of current fad diets discussing their history, proposed mechanisms of action and identifying ones that are healthy and those which are not:

Before you dive in, have you thought about expanding your diet and nutrition knowledge through official methods? Take OriGym’s level 4 advanced sports nutrition course to learn all you need to know about food and nutrition

You should also download our free course prospectus to find out more about our courses.

What Are Fad Diets?

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A fad is a widespread craze or burst of revived enthusiasm towards a given thing which is usually short-lived. 

A fad diet is one that becomes very popular in a short period of time, typically because of its extremely promising claims (usually lacking substantial evidence) or results achieved by its followers (within a short time span). 

Fad crash diet claims will usually revolve around; a proposed theory around a certain mechanism (e.g., fasting and weight loss), demonizing and or inflating a food or food group (e.g., sugar is toxic), your approach to eating (either eating slowly or focusing on food volume) and even a given supplement.

Proponents and creators of these diets will almost always be pushing these as a means of weight loss or, more specifically, rapid weight loss.

Whilst rapid weight loss may be beneficial in some situations, for example, an extremely overweight individual that needs drastic weight loss before a critical surgery, the average person is more likely to suffer from detrimental side effects, especially if undergoing a diet like this without clinical supervision or expert guidance and support.

Rapid weight loss can, however, increase loyalty to an approach for a longer period of time. 

However, the reality is that when we see others achieving rapid weight loss due to the type of diet they follow, as well as the influx of support and advocacy online, these people ultimately reach a point where their weight loss plateaus or stops altogether. 

This then results in a wave of new dieters who are unfortunately predisposed to follow a similar journey while the original dieters enter into a negative mindset, believing that it is their own fault for their lack of progress and not the fault of the so-called “best fad diets for fast weight loss”. 

They then continue with further dieting, either with the same approach or through adopting another of the top fad diets. 

These diets make lofty promises but are often implemented quite poorly and are overall potentially harmful. The focus for many of these diets is weight change and not specifically a healthier lifestyle which ultimately sets a dangerous precedent.

Some simple facts on fad diets clearly demonstrate the ambiguous and risky nature of these trends:

  • 52% of 2000 participants in a study admitted that they were confused as to which fad diets were sustainable in the long term.
  • It is regularly reported that around 95% of diets fail.

Download our FREE food diary to help keep track of your food intake!

Popular Fad Diets That Work

Before diving into the list, it’s important to preface that many of these “fads” are not indeed fads at all. Rather, these diets have been developed over time with a health intention in a clinical or research setting by an expert team of scientists. 

Many people believe them to be fads because marketers have promoted their benefits beyond what has been clinically substantiated and the proposed benefits have yet to be fully elucidated by data.

Here is a list of “fad” diets that are actually clinically validated approaches to improving certain health outcomes and biological markers.

The Mediterranean Diet

do fad diets work

The Mediterranean diet originates from its namesake area. It is based on the intake of the native populations of the Mediterranean who have been found to have a lower risk of many non-communicable diseases and all-cause mortality.

It is high in vegetables, fruits, legumes, nuts, beans, cereals, grains, fish, and unsaturated fats such as olive oil. Olive oil is also one of the top foods for better lung health

This diet usually includes a low intake of meat and dairy foods and little to no highly processed foods or foods with added sugars.

If you’re asking “do fad diets work?” then usually the answer is no. However, as a dietary approach, the Mediterranean diet is fairly flexible and doesn’t advocate restricting any of the major food groups. It promotes an overall healthier lifestyle in terms of actual health behaviours. It is also considered more sustainable than its Western diet counterpart in terms of the ability to adhere to this approach as well as its environmental impact.

The benefits of this dietary practice are extensive and include;

  • The likelihood of cardiovascular diseases is lessened
  • There is a reduced chance of certain cancers
  • Less risk of developing neurodegenerative diseases
  • There is also scientific evidence that proves a reduced risk of obesity and improved weight management when compared to Western diets.

Whilst it has been marketed as one of the well-known types of fad diets, this is arguably one of the most overall healthy dietary approaches that an individual can follow.

The DASH Diet

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The DASH (Dietary Approaches to Stop Hypertension) diet has a very specific health focus; the aim of this diet is to improve blood pressure markers in those with dangerously high blood pressure.

High blood pressure is linked to a number of serious diseases, including heart disease, stroke, and kidney failure.

The main dietary focus of the DASH diet is that it is low in salt. However, the diet is also rich in fruits, vegetables, whole grains, low-fat dairy, and lean protein.

Fortunately, a lot of these types of foods are also some of the best energy-boosting foods!

The DASH diet has been clinically verified in many scientific trials with most being associated with lowering blood pressure. There is additional data showing that adhering to the DASH diet also lowers the risk of adverse cardiac events, stroke, type 2 diabetes, obesity and even some cancers.

Ketogenic Diet

interesting facts about fad diets

The ketogenic (keto) diet is one of the low carb fad diets which promotes a high fat, low to no carbohydrate and moderate protein dietary intake.

The aim of the diet is to achieve ketosis; a metabolic state in which fat (in the form of a metabolite referred to as ketones) becomes the predominant source of energy in the body instead of carbohydrate.

Figuring out what to drink is one of the understated challenges of the keto diet as just drinking water can soon become boring! Read our article on keto-friendly drinks instead of water for some great inspiration.

The diet was originally used as a successful therapeutic approach to treat epilepsy. This is because ketones are proposed to have an anticonvulsant effect, as well as an impact on neuronal metabolism, synaptic and neurotransmitter function.

It has piqued interest as a means of achieving significant weight loss and as a treatment approach for type 2 diabetes. 

Those who trial a keto diet typically experience rapid weight loss in the initial phases. This is due to changes in water, glycogen (stored carbohydrate) and food in transit (through our digestive system). 

This has led to marketers promoting it to the general population, and as a result, it has become renowned as one of the latest weight-loss fad diets.

A keto diet can be highly successful when implemented correctly, whether under clinical supervision or when supported alongside a qualified practitioner. It is a rigid diet, mathematically and individually calculated, and medically monitored.

The issues around keto arise when it is implemented poorly. As mentioned, it is a rigid approach that is also highly restrictive. 

It can have an impact on an individual’s relationship with food and be socially detrimental. Importantly, metabolic adaptation takes time and this initial period of adaptation (when switching to the approach) can be stressful, lead to fatigue, and even cause “keto flu”.

Keto can be successful in the right circumstances, but it should not be mass-marketed as a type of weight-loss fad diets.


the dangers of fad diets

Volumetrics could be considered a fad diet, however, it is rooted in solid science and proposes a dietary strategy that has support from clinical data.

As opposed to the current weight management convention, the Volumetrics diet is all about eating as much as you can whilst still losing weight and managing a healthy lifestyle

The foods you’re consuming however are “calorie efficient” i.e., they provide a lot of volume for the number of calories. Studies have linked foods that are lower in calorie density to improved weight loss and management.

Volume is critical here as the more food volume we consume the greater the satiation effect. As more food enters the gut it pushes against the gastrointestinal wall leading to a cascade of hormones being released dampening hunger and increasing satiety.

Whilst the diet itself isn’t necessarily perfect in isolation, it may be a viable approach to combine with other strategies for those who do struggle with satiety, such as combining with a higher protein diet which can also be extremely effective in weight management. 

Fasting Or Intermittent Fasting

fad diets research

Fasting in and of itself is simply a period of time in which you restrict yourself from eating or are restricted from eating. 

Take the time between your last meal and the first meal of the next day for example; hence why we call our first meal “breakfast” – we’re breaking a fast.

There are many iterations of fasting, from fasting windows in a day to whole day fasts to even multi-day fasts. Some forms of fasting are even based around culture and religion, like Ramadan for example.

Fasting has become one of the types of fad diets following its rapid rise in popularity thanks to Michael Mosley, who worked alongside channel 4 to air a number of shows on the subject and its effectiveness as a weight-loss tool.

Whilst fasting has been proven in academic studies to be just as effective as a calorie-controlled diet for weight management, its utilities extend far beyond that. 

It has also been shown to reduce the effect of ageing and improve health markers and outcomes in; diabetes management, hypertension, inflammatory conditions, cardiovascular disease and function, cancer treatment and even neurodegenerative conditions

Learn more interesting facts about fad diets, particularly intermittent fasting and its benefits and risks, from our recent article.

The Flexitarian Diet

weight loss fad diets

The flexitarian diet is one that encourages a mostly plant-centric lifestyle while allowing for the intake of some meat and other animal products in moderation. Essentially, it is a more flexible version of vegetarianism or veganism and could be a useful intermediary before shifting to a completely plant-based diet.

This approach doesn’t place limits on calories and doesn’t require the in-depth counting and regulating of macronutrients that you might see in the keto diet, for example.

Like the majority of the fad food diets in this article, the flexitarian also encourages the limited intake of sugary and processed foods. Try one of OriGym’s favourite healthy ice creams if you need a sweet fix!

Studies have shown a flexitarian diet to be beneficial for bodyweight metrics, improved markers of metabolic health, blood pressure, and a reduced risk of type 2 diabetes. 

The flexitarian approach may also be a useful dietary strategy as part of the overall therapeutic treatment of inflammatory bowel diseases (such as Crohn's disease).

Low-GI or Zone Diet

best fad diets that work

Low glycaemic index (GI) diets were originally introduced to treat diabetes and metabolic syndrome (pre-diabetes).

The glycaemic index ranks how rapidly blood glucose levels rise following the ingestion of a given food. The higher the score on the index, the more rapid the associated rise in blood glucose.

For the management of metabolic conditions like diabetes and metabolic syndrome, mitigating or implementing better control over post-prandial (after a meal) blood glucose levels will improve health outcomes.

Whilst these types of food improve metabolic conditions, the associative rapid weight loss which has also been found in some studies has led to the promotion of this diet as a weight loss diet, and it has subsequently become a fad diet.

The Zone diet focuses a lot on counting macronutrients, with a specific and rigid ratio of 40% carbohydrates, 30% protein, and 30% fat. Ultimately, these food regulations were designed to become a complete lifestyle change and be continued throughout life.


fad diets history

The low-FODMAP diet was designed to treat irritable bowel syndrome (IBS). FODMAP stands for “fermentable oligosaccharides, disaccharides, monosaccharides and polysaccharides”.

These are difficult to digest carbohydrates which can trigger IBS symptoms. Each of these types of compounds has certain foods associated with them:

  • Oligosaccharides: wheat, legumes, some fruit, some vegetables including onions and garlic. 
  • Disaccharides: lactose based foods, including milk, cheese, yoghurt. 
  • Monosaccharides: fructose based foods, including a variety of fruits such as mangoes, and also foods such as honey.
  • Polyols: other fruits and vegetables, including blackberries, and also low-calorie sweeteners. 

The current body of evidence strongly supports the use of the low-FODMAP diet as a therapeutic treatment for IBS.

Due to some evidence attached to weight change following the diet it has been promoted wrongly in some instances as a weight loss diet, leading to the perception of it being another fad.

As far as the benefits of fad diets go, this one is definitely more of a lifestyle change that will improve the quality of life of IBS sufferers rather than those without the condition just looking to lose weight.

Elimination Diets

information about fad diets

Elimination diets have been used to identify certain foods which may be causing symptoms associated with food intolerances. These symptoms include:

  • Acid reflux
  • Bloating
  • Flatulence
  • Cramping
  • Diarrhoea
  • Skin rashes (even inflaming psoriasis)

These diets follow the approach of excluding all the foods which may trigger said symptoms. The food/food groups typically restricted are; dairy, gluten, FODMAPs, caffeine, eggs, food colourings, food sweeteners.

Learn about the health benefits of eating eggs before you start removing them from your diet.

Foods are slowly reintroduced to the diet to determine the culprit of the undesired symptoms. Some may experience minor weight loss with these diets due to the initial restrictive nature but, it should be noted, that this is not a weight loss diet. 

It serves a very specific purpose and is usually carried out alongside a trained professional healthcare provider or nutritionist in order to treat food allergies, and therefore is not one of the food fad diets. 

A food diary is an excellent tool in helping you keep track of your diet!

The Dangers of Fad Diets: Unhealthy, Misleading, and Potentially Harmful

Whilst there are a few dietary approaches that offer health benefits and are validated in their claims by substantial bodies of evidence, there are quite a few diets out there that aren’t.

These are your prototypical types of fad diets; more often than not these are designed for money generation rather than an interest in improving health. Either that or the creators are simply warping scientific research to fit their narrative or making claims up completely.

A lot of people wonder “why can fad diets be dangerous?” so we’re going to go over some of the very worst perpetrators and discuss the negative effects of fad diets; those “true” fad crash diets that are almost always going to result in more bad than good.

The Atkins Diet

fad diets dangerous

Arguably, fad diets history begins with the “original” low carb fad diet, the Atkins diet. It was first introduced in the 1960s and was based on the theory that a lower carbohydrate diet will improve weight loss outcomes.

The main principles of this diet were that the individual should limit their carbohydrate intake to no more than 20g a day whilst continuing to eat as much protein and fat as desired. This has a similar grounding as the keto diet in that the lack of carbohydrate stimulates ketosis, rendering fat as the body’s primary energy source.

Whilst rapid weight loss has been seen in low carbohydrate approaches, the reasonable healthiness of these fad diets and their effects has come into question. 

The long-term successfulness of low carbohydrate approaches is also questionable given that some data has shown that less than 1% of dieters maintain the initial weight loss after one year.

Relating back to the Atkins diet itself, a major critique of this approach is that it allows for unlimited intakes of dietary protein and fat. Whilst the notion that weight gain with protein overfeeding is unlikely, the data on fat is much more condemning.

If you need more information on sources of protein then read our recent post on vegan and vegetarian protein sources here

Additionally, a highly restrictive diet such as the Atkins approach will increase the risk of nutritional deficiencies, which itself can have serious health implications.

Rapid weight loss fad diets are enticing but the goal should be to approach weight loss in an overall healthy manner which sets an individual up for long term success. The Atkins diet fails to meet this requirement and deserves its fad diet title.

The Paleo Diet

fad diets and their effects

As far as unhealthy or “stupid” fad diets go, the Paleo diet isn’t the worst for its potential health effect. 

The approach advocates animal and plant-based food sources (unprocessed) of which include; fruit, vegetables, meats, fish, healthy nuts, seeds, beans and legumes. It suggests minimizing as best as is feasibly possible of all processed foods, added sugars, dairy and dairy products as well as grains.

Studies evaluating this dietary approach have found it to be beneficial for improving blood sugar control, weight loss outcomes, fatty liver status and cardiovascular risk factors.

Whilst the diet itself isn’t necessarily the worst you’ll come across amongst fad diets, the premise of which it’s based is ludicrous; it aims to mimic the dietary patterns of our hunter-gatherer ancestors, however, assumes they had one universal diet. 

Additionally, life expectancy was much lower in our ancestors so to cite longevity as a potential health benefit of the diet is rather misleading. 

Additionally, cutting out certain food groups, like dairy and grains, runs the risk of nutritional deficiencies. Dairy and dairy products, in particular, are one of the most nutritionally dense foodstuffs on the planet and they have a whole range of potential health benefits.

If you’re looking to brush up on your health and nutrition knowledge, read some of OriGym’s guides:

The South Beach Diet

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One of the more familiar fad diets examples, the South Beach diet became popular in the early 2000s following celebrity endorsement.

The diet itself is somewhat of a mix between a low carbohydrate and low G.I dietary approach, taking the latest fad diets research and adapting it. The focus, as the creators describe, should be focusing on the “right” carbohydrates.

The original intention of the diet was to serve as a therapeutic treatment for patients with cardiovascular diseases and diabetes. However, it’s the effect on aiding individuals to rapidly lose weight soon made it more popular as a weight loss diet.

The diet itself is split into three phases:

  • Initial rapid weight loss phase: the initial “kick” involves three balanced meals a day with between-meal snacks aimed at tackling hunger. Foods are limited to lean meats, seafood, minimal dairy, fruit and vegetables.
  • Achieving the target weight phase: this phase involves a reintroduction of some “good” carbs; grains, root vegetables, beans, legumes etc. with some minimal allowances for processed foods. This phase continues until the individual has achieved their target weight.
  • Pivoting to a lifestyle: this phase focuses on the individual making good food choices and maintaining their new weight in the long term while enjoying all foods in moderation.

This is certainly not one of the worst fad diets on the market, but it does accentuate its own claims, with one report finding that over 66% of the claims made in the diet book were false.

The Carnivore Diet

truth about fad diets

The Carnivore Diet is a highly restrictive approach that includes only meat, fish, and other animal-sourced foods (like eggs and certain dairy products). All plant-based foods, including fruits, vegetables, legumes, grains, nuts, and seeds are excluded. It has also been described as a zero carbs diet and animal-sourced foods diet.

The creator, Shawn Baker, claims that following his approach will assist with weight loss and weight management, improve blood sugar control as well as alleviating mood issues.

Whilst a higher protein diet such as this will be beneficial for weight management and blood sugar regulation, the highly restrictive principles of this diet are major red flags. Following a diet like this may leave you susceptible to many nutritional deficiencies. 

Fibre is just one nutrient to highlight as it is unlikely you will be achieving adequate intake following this approach. Fibre has an important role in our digestive system and sufficient intake is useful for cholesterol profile and total cholesterol level management as well as reducing the risk of certain cancers. 

To learn more about the benefits and risks of this diet, read our nutritional guide on the carnivore diet.

The Dukan Diet

successful fad diets

The Dukan diet is a four-phased approach to weight loss which gradually becomes less restrictive.

The initial phase of the diet cuts out virtually everything bar lean protein; no fruits, veggies, legumes, grains, dairy etc. Dieters are allocated 1 ½ tablespoon of oat bran daily.

The second phase of the diet reintroduces a small number of non-starchy veggies, such as leafy greens and eggplant, every other day and increases oat bran intake to 2 tablespoons daily.

The third phase allows for unlimited protein and veggies, some carbs and fats, and up to 2 ½ tablespoons of oat bran a day.

The fourth and final phase is loosely based on the previous phase with an increase of 3 tablespoons of oat bran per day.

An approach like this is likely to result in rapid weight loss which we previously cited as a means of increasing adherence but the over-restrictive approach of the diet is unnecessary and potentially harmful. Overly restrictive diets may result in binge eating, social avoidance, nutritional deficiencies and a preoccupation with food and dieting.

While the diet requires a calculation of your goal weight, the subsequent phases have little to no modification: it is, for all intents and purposes, a “one size fits all” approach.

Slimming World/Weight Watchers’ Clubs

fad diets can be dangerous because

These two programs work off of very similar models: weekly accountability checks, a focus on more nutrient-dense foods, and group weight-loss support. 

Where the issues lie with these programs is from a number of elements: the enforced morality around certain foods, even going as far as labelling them “syns”, the lack of scientific basis for certain approaches, such as unlimited intakes of certain foods, public weighing (and in some cases shaming due to lack of weight loss), and an overall lack of empowerment towards the dieter. 

These can be labelled as “successful” fad diets only for as long as you’re on them and not afterwards, as individuals are not educated or supported enough to be able to eat healthily and manage their weight on their own.

These are money generating clubs and schemes that are altogether not in the best interest of the individual. 

Clubs are also not managed uniformly across the board. Lead consultants invest in the program(s) and then are more or less allowed to provide the service as they interpret. Whilst some may operate in a healthful way, many are not, and most of the consultants are not qualified to run a nutritional and behavioural intervention.

Becoming a sports nutritionist is a more productive and efficient way of learning about the principles of health and nutrition and then sharing that knowledge with somebody else.

It would be hard to call these fad diets examples as they are expected to remain popular and therefore won’t be going anywhere anytime soon. Plus they’ve actually now been integrated as an outsource for weight management patient referrals by the NHS; despite being built on fad dieting principles.

The Human Chorionic Gonadotropin (HCG) Diet

fad diets examples

Arguably one of the more dangerous fad crash diets, the HCG diet makes extreme claims around rapid weight loss and accelerated metabolic rate.

HCG is a hormone produced in early pregnancy signalling to the body that it is pregnant. It is theorized that HCG elevates metabolism, reduces hunger, improves mood and increases localized fat loss.

The original diet consisted of an ultra-low-calorie diet of around 500kcals per day coupled with an HCG injection. HCG products are now found in various forms, including oral drops, sprays, and meal replacements.

If you’re interested in meal replacement shakes then read our nutrition and purchase guide to learn how to use these products safely.

The dietary approach is broken down into three phases;

  • Initial phase: for the first 48 hours of using HCG, you are prescribed to eat plenty of high-fat, high-calorie foods (which itself is counter-intuitive for weight loss).
  • Weight loss phase: whilst maintaining HCG usage pivot to incorporating the 500kcal ultra-low-calorie diet for the next 3 to 6 weeks.
  • Maintenance phase: cease HCG usage. Gradually increase food intake again whilst mitigating sugar and starch for the next few weeks.

In a study into the proposed effectiveness of HCG injections, it was found that the effects on weight loss, hunger, mood improvement and body measurements were identical in both the HCG injected group and a placebo group.

The dietary approach has been called dangerous, illegal and misleading by various governing bodies. Many fad diets can be dangerous because of the restrictive nature and lack of sufficient nutrition involved yet the HCG diet takes the negative effects of fad diets to a new extreme, making it a diet to avoid completely.


facts on fad diets

Going in the face of fad dieting convention, the creators of the Whole30 approach state that this is not a “diet”, a weight-loss plan, or a quick fix. Rather, the Whole30 approach was designed to “change your life”, apparently doing so by eliminating cravings, rebalancing hormones, curing digestive issues, improving medical conditions and boosting energy and immune function.

The diet itself is one of the eyebrow-raising restrictions. The approach involves 30 whole days (without any real explanation as to why it must be 30 days) of no sugar, alcohol, grains, dairy and legumes. 

Foods allowed included meat and poultry, fish, fruit and veg, nuts and seeds, and some fats (such as coconut oil and ghee). Processed foods are deterred from.

There is no cheating on these rules allowed during this month: if you do eat something from the off-limits list then you have to start the month again.

Whilst reducing processed foodstuffs may be potentially beneficial for health, again, cutting out nutritionally dense groups (like dairy, grains and legumes) is unnecessary and potentially harmful.

Unfortunately, this is another example of fad diets that don’t work: with no education or long-term plan on weight management and nutrition, any weight that is lost during these 30 days is more than likely to be put straight back on once the fad diet is finished.

Short term, highly restrictive and next to no scientific basis; the truth about fad diets such as the Whole30 is that they don’t work and can be dangerous.

Raw Food Dieting

benefits of fad diets

Consuming a diet predominantly composed of raw food involves eating mainly unprocessed whole, plant-based, and preferably organic foods. Some iterations of raw food dieting will include non-plant-based foods, such as eggs and dairy products consuming these raw as well.

This means that the food they consume must not be pasteurised, treated with pesticides, or processed either, but instead encourages blending, dehydrating, juicing, or similar practices.

Fruits, vegetables, nuts, seeds, and occasionally raw eggs and dairy usually make up the constituents of the raw food fad diet. Some choose to eat raw fish and meat as well, but this is less common

Find out if tuna is good for you and worth including in your diet.

Followers of raw food dieting believe that standard cooking methods and food processing practices compromise the nutrient content of the food as well as the enzymes required to digest said food.

Whilst some nutrients may be lost if you cook a certain food in a certain way (for instance boiling instead of steaming vegetables), cooking generally enhances the bioavailability of nutrients.

In relation to the enzyme debate, researchers argue that the enzymes present in food are more for the benefit of the given source itself, not necessarily for its predator or individual consuming it. 

Our bodies produce adequate amounts of the enzymes required to break down foodstuffs and this is regulated by our body in response to what we’re eating. As of yet, there appears to be virtually no impact of the cooking process on our body’s digestive and enzymatic ability to breakdown foodstuffs adequately.

While the very nature of this diet means that weight loss is almost inevitable, the lack of certain food groups, as well as inadequate sources of various vitamins, minerals and antioxidants, mean that the body will be liable to a range of other serious health conditions and diseases. 

The pros of fad diets such as this one are vastly outweighed by the risks and dangers to the body.

The Alkaline Diet

effective fad diets

The creators of the alkaline diet claim that a diet lower in acid-forming foods and higher in alkaline foods can promote a better balance of our body’s PH levels, subsequently creating an environment within our body more conducive to optimal health.

Different foods are labelled as either acidic, alkaline, or neutral, including:

  • Acidic foods are meat and poultry, seafood and  fish, dairy, eggs, grains, and alcohol
  • Alkaline foods include fruit and vegetables, nuts and seeds, legumes
  • Neutral foods are natural fats, starchy foods, and sugar

This sounds like a potentially interesting approach to follow however the creators either misunderstand basic physiology and or have warped how our body works to fit their narrative.

Firstly, if our blood PH levels were “unbalanced”, we’d be incredibly ill, even fatally ill.

Secondly, the body regulates its PH very effectively, even in response to food.

Thirdly, we need different PH levels across our body to serve various functions; for instance, our stomach has an acidic environment to aid in the breakdown of foods during digestion.

Advocating an increase in more fruits and veggies and reducing the intake of processed foods and red meat is likely to confer a health benefit, but you don’t have to be following an “alkaline” approach to make those changes.

Again, the negative effects of fad diets seriously outweigh any proposed benefits and should be avoided.

DNA Diets

fad diets that work

DNA dieting is based around the DNA testing kits which are being promoted by companies as a means to provide you with the “perfect” diet match for your genes.

Whilst this sounds like an interesting approach to take for dieting, the current body of research simply does not support the validity of a diet or certain foods being individually suited for your genes.

Preliminary results of the PREDICT study, which looked at 700 identical twins along with 400 non-twins, highlighted the relative insignificance of genes in relation to how we individually respond to food.

The study is evaluating how each and every subject responds to various kinds of food, with a particular focus on changes in blood sugars and fats. 

There are numerous types of fats - learn more about them in OriGym’s health guide.

The results so far show that, as expected, different people respond very differently to the same dietary inputs. If genes were involved in how we respond to food then we’d anticipate identical twins to have similar responses to a given.

There are many reasons as to why one person’s response to food will differ from another; their gut microbiome, muscle mass, hormonal state, sleep and exercise habits etc. 

Unfortunately for proponents of DNA testing kits and diets based on their results, genes do not appear to be a factor in how someone responds to food and are therefore unsubstantiated in their claims.

The Vertical Diet

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Not your typical fad, the Vertical diet is aimed predominantly at exercise performance improvement and increasing lean muscle mass. Creator of the diet, Stan Efferding (world-class powerlifter and professional bodybuilder), claims the diet achieves this by increasing the number of bioavailable foods within your diet. 

These foods are, in his words, easier to breakdown and digest as well as being less irritable and inflammatory to your gut. Restricted foods include FODMAPS such as onion and garlic, brown rice and legumes, and other less easily digested foods.

In terms of food intake, the diet is based mainly around red meat and white rice with some minor allowances for nuts, sweet potatoes, bell peppers, spinach, carrots, chicken stock, salmon, whole eggs, yoghurt, cranberries (and cranberry juice) and oranges.

One good side to this is that cranberries are classed as a super fruit!

Other pros of fad diets such as the Vertical diet include some weight loss, potential reduction of digestive problems, and it may be beneficial to bodybuilders and for gaining muscle mass as the easily digestible food means that more regular meals can be eaten.

Stan states that limiting variability increases your body’s efficiency in digesting foods and absorbing nutrients. However, this claim is not supported by clinical evidence.

As is the case with many of the listed top fad diets, this approach is highly restrictive without substantiated evidence to be so. The risk of nutritional deficiencies and other detrimental side effects (both physiological and psychological) is increased with an approach like this.

One contentious point is the advocacy of red meat. Increased red meat intake has been associated with an increased risk of colorectal cancer, which raises further safety concerns around this dietary approach.

The Mayr Method

latest fad diets

The Mayr method of dieting was created by Dr Franz Xaver Mayr and highlights the importance of gut health and mindful eating practices, such as eating slowly and drinking in between meals.

Dr Mayr believes that health originates in the gut and that we’re effectively “poisoning” ourselves with our current dietary practices.

Whilst the gut certainly does play an important role in health, the Mayr Method does raise some concerned eyebrows.

For starters, to get the “real experience” of the method you’d have to attend one of his clinics which are only located in very few places across the world and will set you back north of $2000 per week.

Secondly, he also advocates a reduction in acidic foods and promotion of a more alkaline diet which would have no real impact on any health outcomes as the body regulates PH effectively itself. 

Thirdly, there is also a demonization of certain foods and food groups, namely dairy and anything containing gluten, which itself can impact a person’s relationship with food and lead to unnecessarily restrictive practices and increase the risk of nutrient deficiencies.

Did you know that milk isn’t keto-friendly? Find out more about milk and milk alternatives in our recent article.

A fourth point to mention is the use of detoxes and fasts throughout the plan aimed at “cleansing” the body. The body is more than capable of doing this itself; if it weren’t, you’d be very ill.

Dr Mayr’s approaches, whilst seemingly successful in the short term, are certainly not rooted in substantiated clinical evidence. A very expensive approach for something that may not even work long term and could be potentially detrimental.

The Celery Juice Diet

pros of fad diets

One of the odder food fad diets on the market, the celery juice diet advocates consuming 16 ounces (470mls) of freshly blended celery juice each morning whilst fasted. For those with a chronic disease, it is recommended to increase this to 24–32 ounces (710–945 ml).

The creator of the diet, Anthony William (aka. The Medical Medium) claims that celery contains hidden mineral clusters which exude many health benefits, including improving, if not curing, autoimmune disease, mental health issues, gut issues, hormonal imbalance and more.

Needless to say, Mr William is unqualified and his claims are unsubstantiated by any clinical evidence.

Whilst celery juice may confer some benefit, such as being extremely hydrating and even being a rich source of phytonutrients, it certainly should not be viewed as the panacea that Mr William is touting.

Detox and Juicing Diets

what are fad diets

Whilst there are iterations of detox diets that are not necessarily juice-based, mostly all of them will fall under the umbrella term of a juicing diet.

These dietary approaches minimize the intake of whole foods in place of blended juices (typically made from combinations of fruit, vegetables, herbs, spices and other plant-based foodstuffs).

Individually, the juices may be of some benefit within the context of an overall balanced diet but when they become the entirety of the diet is where problems may arise. 

Individuals may be at greater risk of deficiencies of certain nutrients on these diets (namely fibre and protein) and research has shown that these kinds of diets are potentially life-threatening with little to no long term benefits.

It should be highlighted that the human body has a highly sophisticated and effective system for detoxification in place and these juices or detoxes will offer no tangible additional benefit on top of this.

A healthy, well-balanced diet ensures optimal physical functioning without the need for fad diets as dangerous as these.

How To Spot Bad Dietary Advice

fad diets list

With such a constant and highly-marketed stream of dietary advice and newfound weight loss tips regularly in the public eye, it can be difficult to separate the dangerous suggestions from the sound advice.

Poor dietary ideas can be hard to detect as many food fad diets are created by doctors, nutritionists or other “experts” who we are more inclined to trust due to the proposed expertise, even if there isn’t substantial evidence proving their claims.

Fad diets often go hand in hand with a cult-like following, with many who have found some degree of success championing the “best fad diets that work” over others, which at times, can be very convincing. 

So yes, it is not always easy to detect poor or harmful dietary advice. There are, however, certain indicators that may make it easier to spot:

  • Is the individual relevantly qualified?
  • Are their claims substantiated with evidence?
  • What is the basis of their diet?
  • Are they able to present evidence in a way that is easily understandable (highlighting a true understanding of said evidence)?
  • Are they selling you something? Is there an “add-on” sale to their dietary approach/mechanism?
  • How extreme are the claims they’re making?
  • Do they have examples of long-term success?

These are just some of the considerations to make when auditing an approach. Fad diets will continue to pop up over time so being able to diligently detect which are and aren’t healthful is critically important.

Who Can Give Clinical Diet Advice?

fad diets that work

One of the unfortunate by-products of increased accessibility and internet usage is widespread unsolicited and unqualified clinical advice.

In relation to diet and nutrition, there are a select few who can give clinical diet advice:

Registered Dieticians (RD)

RDs will have typically achieved a four-year university degree in nutrition and dietetics accredited by the British Dietetic Association (BDA).

The term ‘dietician’ is a protected title in the UK meaning that only those that have earned the relevant qualifications can work as such.

Registered Nutritionists (Associate or registered nutritionists)

Registered Nutritionists will usually have achieved at least a three-year university degree in nutrition along with postgraduate healthcare qualifications. They share and practice evidence-based information. 

(However, there are other methods of becoming a nutritionist).

You can become a registered nutritionist following accreditation from the Association for Nutrition (AfN). The AfN is able to give government-approved accreditation. 

Application to become a registered nutritionist with the AfN is rigorous and requires you to achieve very specific AfN accredited qualifications.

Nutritional Therapist 

Nutritional therapists will have achieved a diploma or undergraduate degree in nutritional therapy accredited by either the British Association for Applied Nutrition and Nutritional Therapy (BANT), Complementary and Natural Healthcare Council (CNHC) or General Regulatory Council for Complementary Therapies (GTCCT). 

Nutritional therapy is a mixture of evidence-based and non-evidence-based information and advice. This form of practice is not therefore suitable for providing clinical dietary advice (which must adhere to evidence-based information).

If you’re wondering whether personal trainers are able to give nutritional advice then find the answer in our article!


There are many iterations of fad diets; some of which are rooted in clinically validated approaches that have been adopted for the public in a different context and some of which are seemingly made up from thin air and could be potentially harmful

Many of the founders of these programs care more for their capacity to gain financially as opposed to actually improving an individual’s health and it’s important to be aware of that if choosing to trial an approach.

Be mindful of the proposed benefits of fad diets as these can actually be potentially harmful and fraudulent, or even promoted by an individual unqualified to do so.

Each individual has unique dietary considerations that no fad diet will ever be able to encapsulate completely. 

There are those which stand above others of course (such as the Mediterranean diet, whose fad status should be disregarded), but even they are not perfect. Finding a diet that meets your physical, psychological and social requirements will ensure a much healthier and happier life than forcing life to fit around a diet that isn’t quite right.

Before you go, check out OriGym’s level 4 advanced sports nutrition course as this will provide you with the right information for you to make informed decisions about your diet yourself! You can also become a personal trainer with us through our REPS and CIMSPA accredited personal training packages.

Don’t forget to download our course prospectus for all the details.


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  8. Lindeberg, S., Jönsson, T., Granfeldt, Y., Borgstrand, E., Soffman, J., Sjöström, K. and Ahrén, B. (2007). A Palaeolithic Diet Improves Glucose Tolerance More than a Mediterranean-like Diet in Individuals with Ischaemic Heart Disease. Diabetologia, 50(9), pp.1795–1807.
  9. Mahdi, G.S. (2006). The Atkin’s Diet Controversy. Annals of Saudi Medicine, [online] 26(3), pp.244–245. 
  10. Rynders, C.A., Thomas, E.A., Zaman, A., Pan, Z., Catenacci, V.A. and Melanson, E.L. (2019). Effectiveness of Intermittent Fasting and Time-Restricted Feeding Compared to Continuous Energy Restriction for Weight Loss. Nutrients, 11(10), p.2442.
  11. Spector, T. (2018). PREDICT Study (Personalised Responses to Dietary Composition Trial). [online] Health Research Authority. Available at: [Accessed 19 Mar. 2021].
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  13. Stelmach-Mardas, M., Rodacki, T., Dobrowolska-Iwanek, J., Brzozowska, A., Walkowiak, J., Wojtanowska-Krosniak, A., Zagrodzki, P., Bechthold, A., Mardas, M. and Boeing, H. (2016). Link between Food Energy Density and Body Weight Changes in Obese Adults. Nutrients, 8(4), p.229.

Written by Dee Hammond-Blackburn

Fitness Content Executive, OriGym

Join Dee on Facebook at the OriGym Facebook Group

Dee holds a BA (Hons) in English Literature, and is currently finishing her MA in Marketing Communications and Branding from Edge Hill University. Her passion for fitness and content writing brought her to OriGym, and she has since become a qualified Personal Trainer and a Sports Nutrition Specialist. Combining her skills in fitness and writing, Dee has a professional interest in fitness blogging, content creation, and social media. Outside of her writing role Dee enjoys reading, healthy cooking, and playing football with her dalmation.

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