The view that sugar causes cancer is prevalent in the popular press and on the internet and it should be avoided.
A number of doctors and naturopaths hold this view. Since starches are digested as simple sugars then it is recommended that starches should also be avoided.
As a result, a low-carbohydrate diet is endorsed. Some ketogenic diets recommend high levels of vegetables which are high in nutrients but low in the amount of energy that is provided. The absence of starch from these diets results in a calorie restricted diet which is possibly ketogenic. If a diet is restricted in carbohydrates, it will be high in fat and protein.