The ketogenic diet, best known as a fat-busting fad, holds promise for treating anorexia nervosa. Following the diet – which contains high amounts of fat, moderate amounts of protein and very few carbohydrates – caused nearly 75 per cent of people with the eating disorder to drop below the threshold for diagnosis in a small study. This is thought to be due to the diet restoring malfunctioning energy release in brain cells, which has been linked to anorexia, thereby lowering anxiety and reducing the compulsion to restrict food.

Mimicking starvation by restricting carbohydrates in a condition characterised by extreme dieting, and with of all mental health conditions, sounds risky. But at the University of California, San Diego, argues that when properly supervised, it could remove the compulsive drive to self-starve. “People tell me clinically, it’s like an addiction, [saying] ‘I crave this’,” he says. “Perhaps if you create that state that they crave while giving them enough food, it can be beneficial.”

Frank and his team asked 22 women with anorexia, whose body mass index (BMI) had risen enough to sit in the healthy to slightly underweight range, to follow a ketogenic diet for 14 weeks, supervised by a dietician, psychiatrist and a peer support counsellor who had experienced anorexia. Their weight, mood and anorexia symptoms were monitored weekly, using questionnaires to track any changes in body image, depression, food-related anxiety and fear of weight gain.

The 18 women who stuck to the diet for the full 14 weeks showed a significant improvement in anorexia symptoms and scores of depression, which commonly occurs alongside anorexia. Thirteen of them (72 per cent) even improved enough to drop below the threshold for clinical diagnosis for both anorexia and depression. “The level of recovery was far better than what we see in other anorexia treatments,” says Frank.

The aim of the study was not to see if the keto diet made the participants gain weight, however, they all stayed in a healthy to slightly underweight BMI range, and didn’t relapse.

Ketogenic diets are named for the way they prompt a metabolic shift that evolved to help us survive times of famine. As plant-eaters, our metabolism runs mostly on carbohydrates, which are broken down into glucose to be burned in the energy-releasing mitochondria in cells.

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When carbs are unavailable, the body adapts to burn fat, releasing it from storage and converting it in the liver to molecules called ketone bodies. These can be burned in the mitochondria in place of glucose.

The diets were invented in the 1920s, not for weight loss, but as a treatment for epilepsy. It was known that fasting for several days could reduce or stop seizures, but as a treatment, it was unsustainable. The ketogenic diet provided a solution: restricting carbs enough to mimic starvation, while providing enough dietary fat so those on it didn’t lose weight.

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In children with anorexia nervosa or other restrictive eating disorders, changes in the brain’s outer layer don’t seem to be due to lack of nutrition alone – and some mirror those seen in other neurological conditions

Research since suggests that epilepsy and many mental health conditions, including anorexia, are associated with problems related to releasing energy from glucose in the brain, and ketone bodies can relieve these problems by providing an alternative fuel.

at the University of California, Los Angeles, who researches and treats eating disorders, sounds a note of caution for anyone considering trying a keto diet for anorexia. “It is important to distinguish between close monitoring from an eating disorder psychiatrist, dietitian and treatment team, and attempting to do this independently.” Until we have more data from large, randomised controlled trials, it is too early to change the way we treat anorexia, he says, which typically involves therapy and nutritional support.

A shipping container holding three mobile flotation tanks is en route to Maui, Hawaii, to tackle a mental health crisis caused by one of the deadliest wildfires in US history. While mostly found in high-end spas, flotation tanks have shown promise as a treatment for anxiety and post-traumatic stress disorder (PTSD). If the roll-out is successful, fleets of the tanks could be sent to disaster zones all over the world.

In August 2023, a series of wildfires erupted on Maui, the worst of which killed 102 people and . In the years since, risks of depression and anxiety have been higher within wildfire burn zones, and there are fears of an unfolding epidemic of PTSD.

“Maui does not have an infrastructure to deal with a mental health crisis of this magnitude,” says , a clinical neuropsychologist who set up the non-profit . “People are self-medicating. There’s a lot of alcohol use; there’s a surge in suicide and PTSD.”

On 2 May, Feinstein announced at the in Los Angeles that the float units would be available for free sessions for first responders and survivors of the 2023 wildfires, while also being used to collect long-term data on flotation as a mental health treatment.

Flotation therapy, also known as Float-REST (reduced environmental stimulation therapy), involves lying in a shallow pool that contains enough dissolved Epsom salts to support the body without effort. The water in the pool and the air above it are kept at body temperature, and with ear plugs to reduce noise and the lights switched off, the brain is cut off from all external sources of sensory stimulation.

The tanks were invented in the 1950s by neuroscientists to answer the question of whether the brain would shut down without this stimulation. The answer was no – people remained conscious, but they did report a sense of deep relaxation.

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Feinstein has since spent more than a decade ’s mental and physical effects. This work has suggested that it significantly reduces anxiety in volunteers without any mental health conditions, and in people with anxiety disorder and other mental health conditions, such as depression and PTSD. It produces an effect that is roughly equivalent to taking benzodiazepines, a type of sedative, says Feinstein.

While the exact mechanisms are still unclear, flotation is thought to work by removing external sensory stimulation and reducing movement, allowing the body and brain to settle into a state of relaxation. Studies have shown that within minutes, and blood pressure falls, while and emotional processing towards a restorative, sleep-like state.

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Feinstein, who has lived in Maui since 2020, has worked with the UK-based company Floataway to design lower-cost modular float pods, which, unlike regular tanks, can be assembled anywhere in a matter of days. The will bring the tanks to the area and is set to start gathering data in the summer. If successful, the aim is to have a fleet of pop-up tanks that can be sent to disaster zones to potentially prevent PTSD.

at University College London, who has studied the bodily basis of PTSD, says that the focus on calming the body is a much-needed change in how we treat the condition. “A core feature of PTSD is hyperarousal, which is accompanied by increased reactivity of bodily responses,” she says. “Flotation is seemingly able to bring about a feeling of internal safety, which an important shift in the understanding and treatment of PTSD.  I’m really excited by this work.”

Need a listening ear? UK Samaritans: 116123 (samaritans.org); US Suicide & Crisis Lifeline: 988 (988lifeline.org). Visit bit.ly/SuicideHelplines for services in other countries.