Another aspect of the low-carb diets worth commenting on is the phenomenon known as ketosis. Although our bodies can burn fat and protein for energy, glucose is the primary fuel of cells. Our brains are especially dependent upon a steady supply of glucose for energy, and this is why we need to maintain a certain blood glucose level for optimal health. We cannot convert fat or protein into glucose, and therefore must consume a certain amount of carbohydrates in order to meet the body’s needs. If the cells in our body are starved of carbohydrates then they produce proteins known as ketones and burn the ketones as an emergency substitute for glucose. This leads to a build up of ketones in the blood, a metabolic state known as ketosis.
Diabetics can go into ketosis, not because they are starved of glucose but because of insulin dysfunction, preventing adequate transport of glucose from the blood into cells. So even though there is plenty of glucose around, the cells can’t get access to it and must rely upon ketones for quick energy. Another way to achieve ketosis, however, is to simply deprive the body of carbohydrates. The Atkins diet recommends decreasing carbohydrate intake to less than 20% of total calories, which is low enough to cause ketosis, and this is, in fact, the goal. Some more extreme low-carb diets call for total carbohydrate intake of 5% or less.
Ketosis is generally considered to be an unhealthy metabolic state. Ketones are acidic, and high levels of ketones in the blood therefore lead to another metabolic state known as acidosis. One side effect of ketoacidosis is a decrease in hunger, and that is likely a major contributor to the apparent short-term weight loss that low-carb dieters experience.
