The basis of many diets in the past was, "If you want to lose fat, you have to lower the fat intake to minimum." That was also what the leading health institutes recommended. But in the last few years that thesis was proven wrong. There are many scientific studies that show that we lose fat faster if we limit our carbohydrate consumption to minimum, while increasing the fat intake.
Sources of energy for the body
Body needs energy for it's activity. In general body gets this energy primary from carbohydrates, then fat and if necessary also from protein. So if you limit the carbohydrate intake to 30grams or less, your body will have to search for alternative fuel source, which is fat. Your body can still manufacture carbohydrates from protein and one of the components of fat (glycerol).
Every organ except the brains and the nervous system can use fatty acids as an alternative fuel source. Actually the brains and the nervous system can function fairly efficiently without glucose (carbohydrates), because they can get up to 75% of energy from ketones. Ketones are a byproduct of the incomplete breakdown of fatty acids in the liver. They are used as fuel for brains and nervous system.
If you stay on the ketogenic diet for few days, the body starts manufacturing more and more ketones and it greatly reduces the usage of glucose. At the same time the conversion of protein to energy is reduced, which is very important when trying to keep lean body mass (muscle). More muscle mass you have, the more calories your body will burn. This is one of the reasons ketogenic diet is so effective.
Body adjustment to the ketogenic diet
Body needs three weeks to completely adjust to the usage of fatty acids and ketones as an energy source. If you try the ketogenic diet the first few days will be like hell, you will not be able to concentrate, you will be nauseous and weak. This is because the body needs some time to adjust to the new energy source. The body is used to carbohydrates and if you just lower your carbohydrate to zero, that will be a big shock. But when the body adjusts you will start benefiting from the ketogenic diet.
When you start eating high fat and low carbohydrate diet you will start influencing mainly two important hormones, insulin and glucagon. Insulin in the body transports nutrients from blood to cells (like glucose to muscles). Glucagon acts as an opposite, it influences the cells to starts releasing the stored nutrients to the blood stream. When there is a shortage of glucose it encourages the lives to produce glucose from other sources and releasing them to the blood, where they can reach any cell in the body.
If you lower the carbohydrate intake, the body gradually starts releasing less and less insulin and more glucagons. That and the small storage of carbohydrates in the blood soon starts to release fatty acids from the fat deposits and transporting them to the liver where they are metabolized. That leads to increase in ketone production, thereby putting the body in the state called ketosis.
How to reach ketosis
There are many different ketogenic diet, which are based on low carbohydrate consumption. I will explain a few of them in the following articles, including with complete diet and training plans.
The basis of all ketogenic diet is that you lower the carbohydrate significantly. The maximal upper limit of the carbohydrate is 30-50g (that depends from a person to person, but if you intake less you will reach ketosis faster), Then you have to increase the fat intake (fat should represent the main source of calories in your diet). Also you should eat about 1-2g protein per kg (1g protein per lbs), so you will not lose lean body mass.
Ketogenic diet benefits over other diets
This was the overview of the ketogenic diet.