5 popular fad diets: The experts opinion

People are always after the fastest way to lose weight, but are these diets sustainable in the long run? We speak to trained dietician and chef, Clare Gray, to find out more.

The media promote a certain type of ‘ideal’ body image which makes many feel that they have to look a certain way in order to be seen as attractive.

Having a smaller waist, a bigger bum, a thigh gap and thinner legs are all amongst the goals that women aim to achieve.

Alternatively, many men believe that they need to be masculine, muscly, physically strong and have a good physique to be desirable.

Clare Gray, courtesy of her Twitter.

Fad diets promise quick weight loss or other inviting health benefits and often include restricting certain food groups, yet there is very little evidence of any long term success from following these plans.

Here is a breakdown of five popular fad diets including the positives and negatives of following them with close reference to trained chef Clare Gray, who is also a registered dietitian in the UK and USA.

1. The Atkins diet

Eating less carbs and lots of protein is key to achieve results from the Atkins diet. Credit: pexels

The Atkins diet involves consuming more protein rich foods such as chicken, pork and beef, and restraining from products containing carbohydrates including fruit, vegetables and whole grains. Positives of following this diet include significant weight loss.

A lot of fat is eaten when following this diet, especially saturated fat, due to the vast consumption of animal products which can, in turn (according to a recent study), increase your cholesterol levels leading to a higher chance of heart failure.


‘It is incredibly unbalanced, low in fibre and low in important vitamins, minerals and phytochemicals.

‘High protein diets can also have detrimental consequences for renal function. Carbohydrates are important for blood glucose regulation.

‘Common side effects of the diet are constipation, lethargy and bad breath (related to the production of ketone bodies). It is unsustainable and harmful.’

2. The Alkaline diet

Eating lots of fruit and veg is key to the alkaline diet.

The Alkaline diet works on the belief that foods which cause an acidifying affect in the body once broken down such as meat, fish, dairy, pasta and bread should be avoided and foods which cause an alkalising affect in the body such as fruits (surprisingly including lemons), vegetables, green tea and apple cider vinegar should all be consumed. The idea is that by doing this, the body’s PH level remains between 7.3 – 7.4, weight will be lost and overall health, improved.


‘There is lots of contradictory information written about this diet. Some sources of information claim a food is acid producing where as others claim it is an alkaline food.

‘The basic principles of this diet is actually in line with typical healthy eating advice. The scientific principle behind this diet is utterly flawed.

‘The body has a number of homeostatic systems in place to ensure that the pH of the blood is tightly maintained, for example, sodium bicarbonate is secreted if the pH of the blood is too low whereas CO2, excreted through respiration is used to remove acid from our blood stream.

‘I wouldn’t advocate this diet, its confusing and unnecessarily complicated and again it is potentially unbalanced – meat, fish (especially oil fish) and dairy provide important nutrients and are part of a healthy balanced diet.’ 

3. The Juice Cleanse diet

Vegetable juices are better for you than fruit juices as they contain less sugar. Credit: pexels

The Juice Cleanse diet aims to eliminate all solid foods and replace them with fruit and vegetable juices from any time period between three days to a few weeks.

Juicing has become increasingly popular over the last couple of years, especially after a documentary called ‘Fat, Sick and Nearly Dead’ in which Joe Cross, an overweight man with a number of health conditions, took on the juice cleanse for 60 full days. He went from 140kg to 95kg and his overall health improved.

This post shows Joe at the start of his juice cleanse (left) and at the end of the 60 days (right). Picture courtesy of Instagram.


‘Juice cleansing is completely unbalanced, unsustainable and expensive.

‘Fruit juices are very high in sugar (a typical glass of orange juice contains 4-6 oranges, you would not comfortably consume that quantity of fruit within one sitting). Vegetable juices are better as they are naturally lower in sugar.

‘All of the fibre is removed through juicing which is really important to help us feel fuller and to maintain our gut health. Using juices as a meal substitute is extremely unhealthy and unnecessary.’

4. The Paleo diet

People following the Paleo diet also believe in natural oils such as coconut oil and natural sweeteners like maple syrup.

The Paleo diet aims to reduce processed items by sticking mainly to the foods eaten by humans in the Paleolithic era.

This diet is sometimes compared to Atkins as it too involves the consumption of protein. Grains, legumes and dairy is not allowed. Nuts and seeds are recommended in moderation, and the growing trend of fermented foods such as sauerkraut and kimchi come in to play with this diet.

The idea of following it is that it results in weight loss, arguably down to the restriction of certain foods. Furthermore, the consumption of more protein leads to feeling fuller for longer.


‘Although it’s less restrictive than Atkins, it is still an unbalanced diet – it’s unadvisable to cut out dairy foods unless there is a specific medical reason to do so. Dairy foods contain important nutrients, in particular calcium. As I mentioned with Atkins, high protein diets such as this can have negative implications for renal function. I wouldn’t advocate this diet.’

5. The 5:2 diet

The 5:2 diet includes five days of eating normally vs. 2 days of fasting.

The idea of the 5:2 diet is to eat freely for five days of the week, and fast for the remaining two – only intaking 500 calories a day for women and 600 for men on these days.

The pros to this diet include eating whatever you want, within reason, for most of the week. However by doing this, on the two days where only a small proportion of the daily recommended calorie intake is being had, energy levels are low and key nutrients are missed out on.


‘Dieting intervenes with our innate hunger and fullness cues. Intentionally restricting so significantly for 2 days of the week, rather than eating in attainment with our bodies requirements, will undoubtedly disrupt our internal satiation and hunger signals. As with all diets this is likely to lead to food fixation and preoccupations, feelings of guilt and shame if you “cheat” etc. This is another example of an unsustainable diet.’


The latest statistics released by Mintel on eating habits show that half of Brits have tried to lose weight in the last year. Two thirds of these people are on a diet most or all of the time.

Helen West, a postgraduate administrator at Kent University, has tried a variety of diets but has found that Slimming World, where she is now a consultant (in Herne Bay), is the most sustainable way of eating.

In this piece of audio, Helen talks about her reasons for choosing to diet, the benefits and drawbacks of following the Atkins diet and the problem with most fad diets.

Aisla Sargent, naturopathic nutritional therapist, tells Food For Thought why she doesn’t condone fad dieting and explains why a healthy balanced diet is essential.

Orthorexia: The unhealthy obsession with clean eating fuelled by the media

New documentary on BBC2 raises the issue of the social media sensation – clean eating. ‘Clean’ sounds great, but what can happen if you go too far with it? Food for Thought investigates…

On Thursday 19 January, an investigative documentary called Clean Eating – The Dirty Truth was shown on BBC2.

The one off programme shows Dr Giles Yeo, a biochemist from Cambridge, talking to various advocates of clean eating while exploring the science or ‘lack of’ behind what they swear by.

Dr. Giles Yeo looking happy, courtesy of his Instagram account.

The investigative report raises several issues such as the complications of clean eating and how it’s fuelled by social media.

In the programme, Ella Mills, also known as Deliciously Ella, who shot to fame by documenting her plant-based food choices online, admits that social media as a whole can drive eating disorders.

Ella celebrates receiving one million Instagram followers by posting a picture on her own account.

She tells Dr. Yeo: ’My problem with the word clean is that it has become too complicated, too loaded – clean now implies dirty and that’s negative and we shouldn’t have that.

‘It’s sad to me that clean has been taken so far out of how I think it was originally meant to be used – as ‘natural’, ’unprocessed’ and now it doesn’t mean that at all it means “diet”, it means “fad”.’

The idea of clean eating is to embrace whole foods such as whole grains, fruits and vegetables and hold back from eating refined grains, unhealthy fats, added sugars and salt, but some people are taking this idea of ‘clean’ too far.

The fixation on eating ‘clean’ can prove to become an unhealthy obsession in the long run which can also be called ‘Orthorexia Nervosa’.

Orthorexia Nervosa

Orthorexia Nervosa is a term defined by Steven Bratman, MD, MPH in 1996, and is used to describe an obsession with healthy eating.

Although this doesn’t necessarily sound like a bad thing, the constant preoccupation with eating only healthy foods can result in psychological problems and can occasionally be dangerous physically.

People with Orthorexia neglect other aspects of life, and feel dirty for eating something that they don’t consider to be ‘clean’.

Steven Bratman, MD, MPH

It is not recognised officially as a disorder but is used alongside others such as anorexia and bulimia. Although people with orthorexia are not focussing on weight, they are focusing on purity.

Steven Bratman believes that the media does have a part to play in the development of Orthorexia.

‘The social media tie in certainly makes sense. In the past, diet ideas have always been spread by media, so one would assume it still happens that way via whatever media is being used,’ says Bratman.

Sarah’s story

Sarah (left) runs with friend. Courtesy of Facebook.
Sarah (left) runs with friend in 2014. Courtesy of Facebook.

Sarah Emily Johnson, 23, fell in to the trap of orthorexia when she moved to Teeside University in 2013.

Sarah had never really cooked for herself before, so when she started her course of Food and Nutrition, she developed a strong interest in healthy foods and consequently followed lots of food blogs on social media.

This interest soon turned into an obsession and Sarah’s food choices were becoming so restrictive that she was only eating around 800 calories daily.

This is an example of the food Sarah would eat in a day.

Preoccupying her time online aspiring to look like these clean eating advocates was also increasing her want to lose weight. Sarah wouldn’t let herself eat anything she considered to be ‘bad’. 

‘I didn’t realise it was a problem when it was happening. It went on for about six months or so, I lost quite a lot of weight and my hip bones were actually sticking out. At the time I thought I looked really good,’ explains Sarah.

After six months of restricting, Sarah lost control and started binging on all of the foods she had missed out on. It wasn’t until she went home for summer that her diet went back to normal.

‘My mam told me a few times that I’d lost weight and then my friend said to me “wow you’re looking really skinny, you’ve got no boobs”.’

This is Emily before she struggled with Orthorexia. She says there are no photos of her during the period of time she was going through it: ‘I don’t think I left the house much, and was still self conscious’. Courtesy of Facebook.

Sarah, who is now doing a Masters in Human Nutrition at the University of Copenhagen, does still struggle with relapsing thoughts to lose weight and restrict her food heavily again.

‘I’d like to say my mindset is completely healthy now but it’s not. I do follow a lot of clean eating things and I try and stay away from that kind of mentality but sometimes I’m like “right ok, I need to get back to that tiny size I was”.

‘It’s really hard to break out of that cycle because you’re continuously surrounded by it on social media – it’s always there these days.’

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Sarah now eats predominantly vegan foods and often cooks fresh. These images, courtesy of her Instagram, show the kind of foods she makes for herself. 

Sarah says she has always known in the back of her mind that her eating habits were not healthy, but it wasn’t until her third year dietetics module where eating disorders were discussed, that she fully realised the dangers she was putting herself through.

‘We’d discuss eating disorders and things like that and you can feel it striking a cold with you and you think “this is something that I’ve done, this is describing me” and its a bit of a shock.’

Sarah hopes to use her knowledge to educate people on what your body actually needs to survive. She no longer approves advice on diets given by people who have no qualifications and thinks that the media has always had a huge part to play in the development and expansion of eating disorders.

Hear full interview with Sarah here: 

Professional opinion

Ailsa Sargent, Naturopathic Nutritionist in Kent.

Naturopathic nutritional therapist, Ailsa Sargent, doesn’t believe in restricting any of the key food groups as they are all essential for a healthy life.

Ailsa, who is based in Kent,  agrees that foods which fit into the idea of ‘clean’ such as avocados, chia seeds and acai are healthy but she wouldn’t recommend anybody living on a diet of just these foods as it wouldn’t be balanced.

Sabine Farren-Hawkins, counsellor and psychotherapist from Kent

Sabine Farren-Hawkins is a qualified humanistic counsellor and psychotherapist from Kent who has spoken to patients with Orthorexia. She has her own methods of helping a client who is suffering with it.

‘I am mainly person centred so the first thing would be to build a therapeutic relationship and then we would explore what lays behind the Orthorexia.

Reasons can range from being influenced by family eating patterns (or fears), to having been diagnosed with an illness such as Cancer. Control usually also plays a part.’

Sabine believes each individual is different and suggests that the way to overcome Orthorexia would differ depending on the underlying reason for developing it in the first place.

From talking to experts and having a chat with a previous sufferer of Orthorexia, it has become clear that the media has a huge part to play in the unhealthy obsession with ‘clean’ eating.

Eating healthy food is good, but obsessing over your food choices and restraining other key food groups is not.

As Dr. Yeo concludes his documentary: ‘The NHS advises us to eat a balanced diet including fruit, vegetables, whole grains, and dairy whilst limiting meat, and the simple if, unfashionable truth is that science has so far discovered nothing to prove otherwise’.