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.
How many calories are there in a gram of fat? Each gram of fat contains 9 calories. Compare this to protein or carbohydrates, which each contain 4 calories per gram, and you can see why a diet high in fat can lead to weight gain. Calorie Density. Sources of calories for the body are divided into those from fat, carbohydrates, protein, and alcohol.