Sufficient dietary carbohydrates prevent excess formation of what?

Answer 1

You eat carbohydrates to get calories, which you need for everything you do (like breath).

Another source of calories is protein, but if you use only protein to provide your calories, you'll get ketoacidosis.

Another source of calories is fat, but if you use only fat to get calories, you'll be at high risk of cardiovascular disease.

Another source of calories is alcohol, but if you use only alcohol to get calories, you'll die of alcohol poisoning.

Etc.

You don't eat carbohydrates to prevent formation of something-- you eat them to give you the energy to do everything that you do. (You probably also need them to replace the carbohydrate components of various important molecules, but anybody who doesn't eat enough for that purpose is somebody who is already dying from malnutrition related to energy needs.)