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.
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.