It’s the low-carb diet promoted by celebrities that promises to help you lose weight effortlessly by simply eliminating foods like potatoes, pasta and bread.
However, while it may help you shed a few pounds, following the controversial ketogenic diet could have serious downsides, including an increased risk of heart attacks.
According to research from the University of Bath, those who followed the plan had elevated cholesterol levels and reduced levels of “friendly” gut bacteria.
These effects occurred after just three months of following the diet, and worse still, those on the ketogenic diet did not lose any more weight than people on a less drastic low-sugar diet.
Experts have warned that people who commit to a ketogenic diet could be damaging their health in the long term.
An example of a variety of ketogenic foods. A recent study conducted in the UK has shown that while a ketogenic diet can help with weight loss, it can come at a high cost in terms of long-term health damage.
A ketogenic diet aims to bring people into a state called ketosis by almost completely eliminating energy-dense carbohydrates.
This means no bread, pasta, rice, no starchy vegetables like corn, beans and squash, and almost no fruit.
Without carbohydrates, the body starts burning stored fat for energy, which helps people lose weight.
In the latest study, experts took 53 healthy adults and randomly assigned them to one of three diets.
One was a low-carb ketogenic diet and another was a low-sugar diet also designed to help people lose weight.
The final diet tested was a “moderate sugar diet” designed to mimic the average food intake of people living in high-income countries such as Britain, which served as a control for the experiment.
Researchers then measured weight loss and other health indicators four weeks after the start of the study and again at the end of the 12-week study.
Analyzing the results, the scientists found that people who followed the ketogenic diet lost only slightly more weight, losing just over 6 pounds (2.9 kg).
Those who eliminated sugar from their diet lost about 4.5 pounds (2.1 kg).
However, those who followed the ketogenic diet also showed a number of worrying health indicators.
Experts found that participants who had cut back on carbs had elevated levels of bad cholesterol, including a specific type linked to dangerous plaque buildup in the arteries.
In contrast, a low-sugar diet reduced the amount of bad cholesterol in people’s blood.
Additionally, a separate examination of the participants’ gut microbiome — the collection of microscopic organisms in the digestive system — found that those on a ketogenic diet had reduced levels of a bacteria called Bifidobacteria.
This bacteria, often found in probiotic treatments, helps produce B vitamins, prevents harmful bacteria from settling in the intestine and also lowers cholesterol.
Again, in contrast, the low-sugar diet had no significant impact on gut microbiome composition.
Finally, those on a ketogenic diet also showed signs of insulin resistance as their body forgot how to handle carbohydrates, which meant that if they returned to a normal diet, they could be at higher risk of developing type 2 diabetes.
Actress Gwyneth Paltrow has already advocated the ketogenic diet as a way to improve health. Here she is pictured in June of this year.
Jennifer Aniston has been an advocate of cutting carbs in the past, though she has since said she eats them in moderation. She is pictured here in a photo from early February of this year.
Lead researcher Dr Aaron Hengist, an expert in nutrition, exercise and metabolism, said the results showed weight loss was not the only health measure to consider when it came to weight loss diets.
“Despite reducing fat mass, the ketogenic diet increased levels of unfavorable fats in the blood of our participants, which, if sustained for years, could have long-term health implications, such as increased risk of heart disease and stroke,” she said.
Dr Russell Davies, a gut microbiome expert who led this part of the study, added: ‘Dietary fibre is essential for the survival of beneficial gut bacteria such as Bifidobacteria.
‘The ketogenic diet reduced fibre intake to around 15 grams per day, half the intake recommended by the NHS.
‘This reduction in Bifidobacteria could contribute to important long-term health consequences, such as an increased risk of digestive disorders such as irritable bowel disease, an increased risk of intestinal infection, and a weakening of immune function.’
Professor Javier Gonzalez, another expert in nutrition, exercise and metabolism, said increased insulin resistance among people on the ketogenic diet was also a potential health concern for the future.
“The ketogenic diet reduced fasting glucose levels, but it also reduced the body’s ability to process carbohydrates from a meal,” he said.
‘This insulin resistance is not necessarily a bad thing if people are on a ketogenic diet, but if these changes persist when people return to a higher-carb diet, it could increase the risk of developing type 2 diabetes in the long term.’
The authors concluded their study by saying that while more research is currently needed on these diets, if people want to lose weight, they would recommend a low-sugar diet.
Fellow author Professor Dylan Thompson, an expert in human physiology, said: ‘The ketogenic diet is effective for fat loss but comes with a range of metabolic and microbiome effects that may not be suitable for everyone.
‘On the contrary, sugar restriction supports government guidelines to reduce free sugar intake, promoting fat loss with no apparent negative health impacts.’
Actress Halle Berry is a staunch follower of the ketogenic diet and has been following it for over 30 years to manage her type 1 diabetes. She is pictured here in April.
Reality star Kourtney Kardashian has also endorsed the diet and has even shared her recipes online.
Ketogenic diets generally advocate reducing carbohydrates while consuming a higher amount of fat, with a moderate amount of protein.
A ketogenic diet consists of 75 percent fat, 20 percent protein, and only 5 percent carbohydrates.
This is radically different from the NHS’s healthy balanced diet advice, which recommends 30 percent fat, 15 percent protein and 55 percent carbohydrates.
A typical person following a ketogenic diet is advised to consume only 20-50g of carbohydrates per day.
Since a slice of whole wheat bread contains 14 g of carbohydrates and a banana 20 g, this means that people on a ketogenic diet need to plan their meals carefully.
Despite multiple studies pointing out the potential dangers of a ketogenic diet, it has become increasingly popular.
Several celebrities including Gwyneth Paltrow, Jennifer Aniston, Halle Berry and Kourtney Kardashian have spoken about following a low-carb diet in the past.