- Weight loss
- Allergy or disease
Limiting your carbohydrate intake can be beneficial to your health because abstaining from them typically means you will have low insulin levels throughout the day. Regular, prolonged elevated insulin levels are linked to cardiovascular disease (1, 2), cancer, and obesity.
When insulin levels are low, your body finds it easier to burn body fat. By not eating carbohydrates, and therefore consistently keeping insulin levels low, your body has more time to burn body fat than on a medium or high carb diet. This often results in weight loss.
In addition, many people report that eating fatty foods is more satiating than eating high carb foods, meaning they take in less total energy throughout a regular day of eating.
Allergy or diseases
Some people suffer from allergies or intolerance of certain foods, such as gluten. Most foods containing gluten are high in carbohydrates. It therefore makes sense to eliminate them altogether. The same could be true for other allergies. If there is an overlap with carbohydrates, one might choose to adopt a ketogenic diet.
Other than that, people report that bloating, reflux, migraines, lethargy, and mood swings, greatly improve or disappear when switching to a ketogenic diet. Although such evidence is anecdotal, it is omnipresent.
Lastly, diabetes type II can be reversed completely (1, 2) by adopting a balanced ketogenic diet, and type I diabetes can also be controlled much better when adopting a very low carb diet.
What (not) to eat
Carbohydrates are one of the four main energy sources (macronutrients): carbohydrates, protein, fat, alcohol. When you do not eat carbs, you need to get more energy from fat. On a ketogenic diet, you eat a lot more fat than on a high carb diet, and about the same amount of protein.
People on a ketogenic diet do not eat:
- Bread, pizza, tortillas
- Rice, grains
- Potatoes, fries, polenta, starchy vegetables
- Candy, pastry, dessert
- Regular soda, ice tea, sweetened drinks
- Beer, cocktails
- Most fruits, fruit juice
They instead eat more:
- Butter, cream
- Bacon, fatty cuts of meat
- Fatty fish
Many people on the ketogenic diet still eat a fair amount of vegetables, as long as they are not starchy.
It is not required to eat more meat on a ketogenic diet than on any other diet. Eating a vegetarian ketogenic diet is possible, with some creativity. Eating a vegan keto diet is very complex, but it has been done.
It takes the human body a while to get used to primarily burning fat for fuel. People report adaption periods ranging from 5 days to four weeks. This depends on how strictly carbohydrates are limited and physical exercise, among other (personal) factors.
During adaptation, some people report feeling under the weather. This is called the keto flu.
One can adopt a ketogenic diet for an indefinite amount of time. It can be used as a short term weight loss diet, or a permanent way of life.
The ketogenic diet is not dangerous when implemented with care. Eating a lot of processed foods is bad, and so is eating lots of heated or processed vegetable oils, regardless of diet.