Posted by 
Low-carb diet changes your metabolic from burning more carbohydrates to burning of more fat than carbohydrates, this is a process known as ketosis.
When human body uses up carbohydrates glucose 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 are changed into acetoacetate, a metabolic fuel that belongs to a family of ketones.
Acetoacetate decomposes to carbon dioxide and acetone, low-carbohydrates dieters and people who are fasting usually have sweet smelling breath.
A healthy liver minimises the acetone lost through the lungs by converting most of the acetoacetate it produces to beta-hydroxybutyrate BHB. This can cause euphoric feelings.
During ketosis, BHB can reach high levels in the brain, where it can bind to the same anxiety-reducing receptors as recreational drugs with similar effects.
Side effects of ketosis are loss of calcium from bones, kidney stones and growth retardation.