An endless stream of diets promise to boost health and shift the scales.

But teasing apart which is actually going to leave you more trim without damaging your health in the long-term can seem nearly impossible. 

Here, MailOnline asks two leading dieticians which regimes are actually best for maintaining a healthy lifestyle…

The keto diet, involves cutting out most of your carbohydrates and adding a high amount of fat, keeps your blood glucose level at a safe but low level, which encourages the body to burn fat for energy, which is known as ketosis

It’s a regime lauded by A-list celebrities including Kim and Kourtney Kardashian, Halle Berry and Gwyneth Paltrow.

The ketogenic diet, also known as the keto diet, involves cutting out almost all carbs and adding a high amount of fat and protein to every meal.

As a result, bread, rice and pasta are completely excluded, as are sweets, chocolate and cakes. Even dairy, fruit and vegetables are limited.

It has been shown to help with weight loss and lower blood sugar levels among type 2 diabetics, according to Dr Duane Mellor, a dietitian based at Aston University in Birmingham

‘It has the pros of being low in sugar, and filling due to protein,’ he said. 


Meals should be based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally wholegrain, according to the NHS

Eat at least 5 portions of a variety of fruit and vegetables every day. All fresh, frozen, dried and canned fruit and vegetables count.

Base meals on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally wholegrain

30 grams of fibre a day: This is the same as eating all of the following: 5 portions of fruit and vegetables, 2 whole-wheat cereal biscuits, 2 thick slices of wholemeal bread and large baked potato with the skin on

Have some dairy or dairy alternatives (such as soya drinks) choosing lower-fat and lower-sugar options

Eat some beans, pulses, fish, eggs, meat and other proteins (including 2 portions of fish every week, one of which should be oily)

Choose unsaturated oils and spreads and consuming in small amounts

Drink 6-8 cups/glasses of water a day

Adults should have less than 6g of salt and 20g of saturated fat for women or 30g for men a day

Source: NHS Eatwell Guide  

The diet aims to force the body into burning fat for energy instead of glucose — a process known as ketosis.

This fat-burning effect of the diet is why it’s marketed as good for weight loss, says Rob Hobson, registered nutritionist and author of Unprocess Your Life.

Additionally, the high fat content can reduce appetite and aide weight loss, he says.

However, the diet — similar to the Atkins and Dukan approaches — is notoriously difficult to stick to. Followers need to have fewer than around 40g of carbs and 75g of protein per day for ketosis to kick in.

Additionally, cutting back on plant-based foods can lead to nutritional deficiencies, warns Mr Hobson. 

‘The initial stages of this diet also incur unwanted symptoms such as headache, fatigue and irritability,’ he said. ‘The low fibre content of this diet may impact on digestion.’

Dr Mellor warns that the high fat diet could, in theory, increase heart disease risk. 

However, this could be balanced out if those following the diet successfully lose weight, as this lowers the chance of developing of the condition, he says.


It won’t come as much of a surprise that dietitians are not fond of a diet that involves only eating meat, eggs and cheese and no vegetables or fruit. 

The incredibly restrictive approach, known as the carnivore diet, stems from the belief that our ancestors mostly ate meat and that today’s diets, which are typically high in carbohydrates, raise the risk of health problems. 

It has been promoted online by the likes of commentator Jordan Peterson and Shawn Baker, an American orthopaedic doctor who believes the diet can help treat anxiety, obesity, diabetes and even arthritis.

The carnivore diet is a version of the Keto diet because, without carbohydrates, the body will burn fat instead.

Benefits of a high-protein diet include feeling fuller for longer, because the nutrient takes longer to digest than carbohydrates.

However, dieticians do not recommend the carnivore approach. 

‘This diet eliminates plant-based foods and sticks to just animal foods so it is restrictive, said Mr Hobson. ‘It is not a diet I would recommend following.

‘The high protein content can help with satiety and increase feelings of fullness and obviously protein has many rolls in the body. 

‘I guess there is the potential for weight loss, given the likelihood you would be eating less calories. But this is likely to be short lived.’ 

Because the diet excludes all fruits, vegetables, grains and legumes, the body will be lacking in vital sources of fibre, vitamins and minerals, explains Mr Hobson. 

Adults should eat 30g of fibre a day to lower their risk of heart disease, stroke and type 2 diabetes, the NHS says.

The restrictive carnivore diet is promoted online by the likes of Jordan Peterson and Shawn Baker, an American orthopedic doctor, who believes the diet can help treat anxiety, obesity, diabetes and arthritis

As well as being terrible for gut health, if followers are eating processed meats in excessive quantities, they could be increasing their cancer risk, Dr Mellor warns.

Health chiefs advise having no more than 70g a day of sausages, bacon or ham to reduce the risk of bowel cancer.

Just like the keto diet, the carnivore diet can be impossible to stick to in the long-term, says Mr Hobson. 

‘Consuming high amounts of meat and dairy foods could lead to eating high amounts of saturated fat, which can increase cholesterol levels and other risk factors for heart disease,’ he said. 

‘Then there is the practicalities of maintaining this diet which could be tricky in social settings.’


It’s one of the biggest health trends of the past decade and it’s hailed as being one of the best diets.

Veganism involves cutting out all meat, dairy and eggs and eating plenty of fruit, vegetables, wholegrains, legumes, nuts and seeds.

Advocates say they can get all the nutrients they need by eating fortified foods and supplements to get enough calcium, iron and vitamin B12, which are difficult to get in high enough quantities while being plant-based.

Vegan diets can be healthy to both us and the planet, they can be nutrient dense, packed with fibre, vitamins and minerals,’ said Dr Mellor. 

‘The downside is that it takes a bit more planning to be healthy, as it can be lacking in nutrients like vitamin B12, vitamin D, iron and iodine, which need to be taken to maker sure that a vegan diet is balanced and healthy. 

‘Also, if you are wanting to eat a vegan diet, it is important to mix sources of protein so that you get the full range of amino acids they contain.’

The Mediterranean has been linked to reducing the risk of heart disease, some cancers, type 2 diabetes and even dementia, according to the NHS

Mr Hobson says the high-fibre diet is not only good for your gut, but also has been associated with a reduced risk of heart disease, type 2 diabetes and some cancers.

However, he warns that the emergence of vegan chocolate, fast food and meat alternatives means there are ‘many more opportunities for vegans to be less healthy’.

These options are ultra-processed and high in salt, sugar and fat, he says. 


Rather than filling up on pasta and pizza, the Mediterranean diet contains an abundance of fresh fruit, vegetables and healthy brain foods like fish and olive oil.

It has long been hailed as the secret behind Italians and Spaniards living long and healthy lives and low rates of obesity and diet-related illnesses.

It’s been linked to a reduced risk of heart disease, some cancers and type 2 diabetes.

That’s why it’s one of the most commonly recommend by dietitians. 

Mr Hobson goes as far to say it is the ‘perfect diet’, with research showing it is a ‘gold standard way of eating’. 

He adds that it contains a wide variety of foods and the diet can be accommodated for a plant-based way of eating as well.  

‘I would most lean toward recommending a Mediterranean diet, as the scientific evidence is strongest for this approach,’ said Dr Mellor. 

But he warns against eating too much pasta, bread and risotto and instead opt for grains and barley.  

He said: ‘A traditional Mediterranean diet is based on the available fresh and minimally processed foods, perhaps when we try and follow it we might go for the less healthy versions with added fat, salt and sugar. 

‘For example, adding a garlic bread to your lasagna.

‘I would encourage people to think about simple dishes made from plants, such as salads and vegetables and adapt it to foods available locally, such as eating pearled barley rather than risotto rice.’

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