The keto diets WRECKS your body: ultra-low carb plan raises cholesterol, reduces 'friendly' gut bacteria... and it's no better for weight loss than other slimming plans, experts discover
It's the low-carb diet promoted by celebrities that promises to help you effortlessly slim down simply by cutting out foods like potatoes, pasta and bread.
However, while it may help you shed a few pounds following the controversial keto diet could have serious downsides, including an increased risk of heart attacks.
According to research from the University of Bath those who stuck to the plan had raised cholesterol levels and reduced levels of 'friendly' gut bacteria.
These effects occurred after just three months on the diet and worse still keto dieters didn't lose more weight than people on a less drastic low sugar diet.
Experts warned that people who commit to a keto diet could be damaging their health in the long term.
An example of a range of ketogenic foods. A recent UK study has shown that while a keto diet could help you lose weight it may come at a steep cost of harming your long term health
A keto diet aims, by almost eliminating energy dense carbohydrates, for people to achieve a state called ketosis.
This means no bread, pasta, rice, and no starchy veg such as corn, beans and squash and almost no fruit.
Without carbohydrates, the body starts to burn stored fat for energy instead, helping people lose weight.
In the latest study, experts took 53 healthy adults and randomly assigned them to one of three diets.
One of these was a keto, low carb diet, with another being a low sugar diet also designed to help people lose weight.
The final diet assessed was a 'moderate sugar diet' designed to mimic the average food intake of people living in high income countries like Britain, which served as a control for the experiment.
Researchers then measured aspects like weight loss and other health indicators four weeks into the study and again at the study's conclusion of 12 weeks.
Analysing the results, scientists found people on the keto diet lost only slightly more weight, shedding just over 6lbs (2.9kg).
Those cutting sugar from their diet lost about 4.5lbs (2.1kg).
However, those on the keto diet also had a range of concerning health indicators.
Experts found participants who had cut carbs had raised bad cholesterol levels, including a specific type which linked to dangerous plaque buildup in the arteries.
In contrast, a low sugar diet lowered the amount of bad cholesterol in people's blood.
Additionally, separate examination of participants gut microbiome, the collection of microscopic organisms in the digestive system, found those on a keto diet had reduced levels of a bacteria called Bifidobacteria.
This bacteria, often found in probiotic treatments, helps produce B vitamins, stops harmful bacteria from taking hold in the gut and also lowers cholesterol.
Again, in contrast, the low sugar diet had no significant impact on gut microbiome composition.
Finally, those on a keto diet also displayed signs of insulin resistance as their body forgot how to handle carbohydrates which meant, if they switched back to a normal diet, they could be at increased risk of developing type 2 diabetes.
Actress Gwyneth Paltrow has previously advocated for the keto diet as way to improve health. Here she is pictured in June this year
Jennifer Aniston has been a fan of cutting out carbs in the past though has since said she does eat them in moderation. Here she is pictured in February earlier this year
Lead researcher Dr Aaron Hengist, an expert in nutrition, exercise and metabolism, said the results showed weight-loss wasn't the only health measure to keep in mind when it came to weight-loss diets.
'Despite reducing fat mass, the ketogenic diet increased the levels of unfavourable fats in the blood of our participants, which, if sustained over years, could have long-term health implications such as increased risk of heart disease and stroke,' he said.
Dr Russell Davies and expert on the gut microbiome, and who led on this portion of the study added: 'Dietary fibre is essential for the survival of beneficial gut bacteria like Bifidobacteria.
'The ketogenic diet reduced fibre intake to around 15 grams per day, half the NHS recommended intake.
'This reduction in Bifidobacteria might contribute to significant long-term health consequences such as an increased risk of digestive disorders like irritable bowel disease, increased risk of intestinal infection and a weakened immune function.'
Professor Javier Gonzalez, another expert in nutrition, exercise and metabolism said the increased insulin resistance among keto dieters was also a potential health concern for the future.
'The ketogenic diet reduced fasting glucose levels but also reduced the body's ability to handle carbs from a meal,' he said.
'This insulin resistance is not necessarily a bad thing if people are following a ketogenic diet, but if these changes persist when people switch back to a higher carbohydrate diet it could increase the risk of developing type 2 diabetes in the long-term.'
The authors concluded their study by saying while further research is needed on these diets currently, if people want to lose weight, they would recommend a low sugar intake one.
Fellow author Professor Dylan Thompson, an expert in human physiology said: 'The ketogenic diet is effective for fat loss, but it comes with varied metabolic and microbiome effects that may not suit everyone.
'In contrast, sugar restriction supports government guidelines for reducing free sugar intake, promoting fat loss without apparent negative health impacts.'
Actress Halle Berry swears by the keto diet and has been following it for more than 30 years to help manage her type 1 diabetes. Here she is pictured in April
Reality star Kourtney Kardashian has also backed the diet and even shared her recipes online
Keto diets typically advocate for cutting carbs while eating a higher amount of fat, with a moderate amount of protein.
A ketogenic consists of 75 per cent fat, 20 per cent protein and only 5 per cent carbohydrates.
This is radically different from the NHS's healthy balanced diet advice which advocates for 30 per cent fat, 15 per cent protein and 55 per cent carbohydrates.
The typical person on a keto diet is advised to only eat between 20g to 50g of carbohydrates per day.
With a slice of wholemeal bread containing 14g of carbohydrate and a banana 20g, this means people on a keto diet need careful plan their meals.
Despite multiple studies pointing to the potential dangers of a keto diet it has become increasingly popular.
A number of celebrities such as Gwyneth Paltrow, Jennifer Aniston, Halle Berry and Kourtney Kardashian who have spoken about being on the low-carb diet in the past.
