NUTRITION PROCTOR CHAPTER 1: SOURCES OF NUTRITION Macronutrients: carbohydrates, proteins and fats CARBOHYDRATES Main function: provide energy for the body  Provide energy for cellular work  Help regulate protein and fat metabolism  Essential for normal cardiac and CNS functioning Average minimum amount needed to fuel the brain- 130 g/day Acceptable macronutrient distribution range for carbs- 45%-65% of calories Glycogen- stored carbohydrate source found in the liver and muscl...