Keto is a low carb, high fat, moderate protein diet designed to force the body into a state known as ketosis, which is a natural state the body uses to produce energy during a food shortage. During ketosis, our bodies produce ketones, which are formed by breaking down fats in the liver.
Other terms which refer to the keto diet include low carb high-fat diet (LCHF), low carb diet, or ketogenic diet.
How Does the Keto Diet Work?
When you consume foods high in carbohydrates, the body will produce glucose and insulin. Glucose is used as the primary fuel source for energy because it is the easiest molecule to metabolize. Fats are not used and are stored away as reserve energy.
The goal of the keto diet is to force your body to use its fat stores as energy, which is achieved not by starving yourself of calories, but by drastically limiting your intake of carbohydrates.
The body reacts to carbohydrate restriction similarly to fasting, in that it searches for alternative sources of energy. In the case of the keto diet, the energy source is provided by ketogenesis, the process whereby fat cells are converted into ketone bodies which the cells then use for energy.
After between 2 to 4 days of "starving” yourself of carbohydrates, which is achieved by eating less than 20 to 50 grams of carbs in a day, the body will start breaking down fat as a source of energy.
Eating high-fat content foods is more satiating than consuming a meal high in carbohydrates, which means that people tend to consume fewer calories per meal on a ketogenic diet. However, this a very personal attribute and varies dramatically between individuals.
Keto diets reduce the level of insulin in the body. Insulin is used to control glucose levels in the blood, but it also triggers the body into storing fat. With less insulin in your blood, less fat will be stored in the fat cells.
Research indicates that weight loss on a ketogenic diet is faster at the beginning than other types of foods. However, it's important to note that this advantage is lost over time.
Ketogenic diets also show promise for short-term improvements in blood sugar levels for type 2 diabetes patients, due to a low quantity of carbohydrate-rich foods which increase the level of sugar in the blood.
Limiting yourself to foods which are high in fats may sound appealing at first, but the truth is you are quite limited in what you can eat because of the carb restrictions.
These restrictions can make eating with family and friends and going out for meals quite challenging. The average American diet consists of about 50% carbohydrates, which can make the keto diet very hard to stick with as a long-term weight loss solution. You may find yourself craving the sweet, juicy flavours of a fruit salad or the crunchy goodness of an apple.
In 1996, Copenhagen University conducted a study on the effects of high-fat diets on athletic performance. [*1] The results indicated lower performance levels in both power output and endurance when compared against high-carb diets. A ketogenic diet may, therefore, not be the best choice for elite athletes.