The term convection generally refers to the movement of fluids, meaning liquids and gases, but in the earth sciences, convection also can be used to describe processes that occur in the solid earth. This geologic convection, as it is known, drives the plate movement that is one of the key aspects of plate tectonics.
The recommended range is 45 â 65% of calories as carbohydrate. For example, if you eat 1600 calories per day, and 50% of those calories are carbohydrate, you would eat 200 grams per day. Athletes need to eat at the high end of the carbohydrate range, to fuel training and competition.
Carbohydrates: Complex Carbs vs Simple Carbs. Carbohydrates are the main source of calories in a healthy diet and are the primary fuel for the brain and muscles. Typically, about three-fourths of daily calories should come from carbohydrates. It's also important to choose the best carbohydrate sources. That means two things: 1  Choose complex carbohydrates, rather than simple carbohydrates. 2  Choose carbohydrates that still have their fiber, like brown rice or brown bread, rather than white rice or white bread, from which the fiber has been stripped away.