Feeling euphoric on a low-carb diet? The effect on your brain is similar to an illicit drug
Some people on very low-carb diets say they feel euphoric, have clear minds and lose their appetite.
Going low-carb might even mimic the effects of GHB – the recreational drug better known as fantasy, liquid ecstasy or grievous bodily harm – on the brain.
To understand why we need to look at how the body processes a very low-carb diet, one that typically limits carbohydrates to no more than 50 grams a day. That’s one cup of rice, two slices of bread or roughly 10% of your total daily energy needs.
Your body thinks it’s starving
A very low-carb diet flips your metabolic switch from burning more carbs than fat, to more fat than carbs. This usually takes a few days in a process known as ketosis.
During this time, your body thinks it’s starving. Once it uses up most of your glucose (carb) reserves, the body stimulates the breakdown of stored fat into fatty acids and releases them into the blood.
When fatty acids reach the liver they’re converted into acetoacetate, an excellent metabolic fuel that belongs to a family of chemicals called ketones. That’s why very low-carb diets are sometimes called “ketogenic” diets.
Acetoacetate decomposes to carbon dioxide and acetone, the smelly solvent best known for its ability to remove nail polish. This is why very low-carb dieters and people who are fasting often have sweet smelling breath.
A healthy liver minimises the acetone lost via the lungs by converting most of the acetoacetate it produces to a more stable substance, called beta-hydroxybutyrate or BHB. And this is where those euphoric feelings could come from.
The molecule BHB, which your body produces during a very low-carb diet, is very similar to GHB, the recreational drug with psychoactive effects.
BHB is almost identical to GHB, the naturally occurring neurotransmitter, called gamma-hydroxybutyrate, that in synthetic form is used as a recreational drug.
BHB and GHB have exactly the same chemical formula. Both consist of just 15 atoms, with the only difference being the position of one hydrogen and oxygen atom. It’s not too surprising, therefore, the two molecules share the same carrier across the blood-brain-barrier, the impermeable tissue that protects the brain.
During ketosis, BHB can reach high levels in the brain, where it can bind to the same anxiety-reducing receptors as GHB. They bind with sufficient affinity that they may have similar effects.
There are no reports of BHB supplements or low-carb diets causing any of GHB’s adverse effects, loss of consciousness, seizures and death.
So, apart from the similar-sounding name, what evidence is there that BHB produced by the liver by people on a very low-carb diet has euphoric, GHB- effects in the brain?
Fasting for the original ‘natural high’
The first case of euphoria directly attributed to ketosis was reported by Walter Bloom, who pioneered therapeutic fasts for obesity in the 1950s. After several days without food, his patients lost their appetite, felt remarkably well, and experienced a mild intoxication:
not dissimilar to the effects of ethanol.
Bloom speculated that acetoacetate had caused the inexplicable jubilation.
Other people have observed similar effects, including three Scottish doctors whose patients fasted for up to 249 days in the 1960s. After several days without food, their appetites subsided and all patients felt an increased sense of well-being which:
in some amounted to frank euphoria.
Unfortunately, no studies of the euphoria reported by low-carb dieters have been conducted, as far as we know.
So, researchers don’t know the exact cause of these feelings. Acetoacetate, acetone and BHB, or any of their metabolites, may all be involved, as well as the effects of low blood sugar, which can cause euphoria and giddiness.
A good place to start might be to image brain activity in people on a very low-carb diet and compare activity with people on a normal, non-calorie restricted diet. The aim would be to see if brain imaging of people on a very low-carb diet has similar effects on brain activity seen when people take GHB.
And if you’re thinking of going on a very low-carb diet to get that high, beware. Side effects include loss of calcium from bones, increased risk of kidney stones and growth retardation.
Special thanks to PhD candidate Ruben Meerman for his input, including his animation of BHB versus GHB.
Low-carb diet may reverse age-related brain deterioration, study finds
A low carbohydrate diet may prevent and even reverse age-related damage to the brain, research has found.
By examining brain scans, researchers found that brain pathways begin to deteriorate in our late 40s – earlier than was believed.
“Neurobiological changes associated with ageing can be seen at a much younger age than would be expected, in the late 40s,” said Lilianne R Mujica-Parodi, a professor in the department of biomedical engineering at Stony Brook University in New York.
“However, the study also suggests that this process may be prevented or reversed dietary changes that involve minimising the consumption of simple carbohydrates,” added Mujica-Parodi.
To better understand how diet influences brain ageing, researchers concentrated on young people whose brains showed no signs of ageing. This is the period during which prevention may be most effective.
Using brain scans of nearly 1,000 individuals between the ages of 18 to 88, researchers found that the damage to neural pathways accelerated depending on where the brain was getting its energy from. Glucose, they found, decreased the stability of the brain’s networks while ketones – produced by the liver during periods of carbohydrate restrictive diets – made the networks more stable.
“What we found with these experiments involves both bad and good news,” said Mujica-Parodi, “The bad news is that we see the first signs of brain ageing much earlier than was previously thought.
“However, the good news is that we may be able to prevent or reverse these effects with diet … by exchanging glucose for ketones as fuel for neurons,” she added in the study, which is published in PNAS.
“We think that, as people get older, their brains start to lose the ability to metabolise glucose efficiently, causing neurons to slowly starve, and brain networks to destabilise,” said Mujica-Parodi.
“So we tested whether giving the brain a more efficient fuel source, in the form of ketones, either by following a low-carb diet or drinking ketone supplements, could provide the brain with greater energy.
Even in younger individuals, this added energy further stabilised brain networks.”
A ketogenic diet is one high in fats and proteins, and low in carbohydrates, forcing the body to burn fats rather than carbohydrates. Primarily used to treat some forms of epilepsy in children, it is also believed that it has potential to help other neurological disorders, including Alzheimer’s disease and Parkinson’s disease.
Dr Katy Stubbs, from Alzheimer’s Research UK, said the research was “very interesting” but needed more investigation. “The ketogenic diet has risks of its own,” she said. “It has been shown that eating such high levels of fat, which generally goes with people eating less fruit and vegetables, has a detrimental impact on your heart, which has dangerous side effects.
“Also, there is a huge amount of evidence showing that the Mediterranean diet is the best diet we’ve got so far for brain and heart,” she added. “That includes a lot of wholegrains. We’re going to need a lot more research if the ketogenic diet is going to be widely recommended as an alternative to that approach as a prevention against dementia.”
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