Content Vocabulary energy glucose fatty acids amino acids toxin calories gram digestion

Three nutrients—carbohydrates, fats, and protein—provide energy the body can use to grow, to move, and to create heat to maintain a steady temperature. energy The capacity to do work or produce heat 2

Energy from Nutrients The body stores extra energy from the carbohydrates, fats, or proteins you eat as glycogen or body fat. 3

Energy from Nutrients Carbohydrates provide the body with its main fuel, glucose. The brain and nervous system depend on glucose for energy to think, to trigger movement, and to send messages between tissues. glucose A simple form of carbohydrate which serves as the body’s sugar 4

Energy from Nutrients Fat supplies energy to the body as fatty acids. Muscles rely heavily on fatty acids to fuel physical activity and movement. fatty acids Building blocks of fat that supply energy fuel for most of the body’s cells 5

Energy from Nutrients Protein supplies energy as amino acids. In difficult situations when the body is stressed, it can burn amino acids from protein at a greater rate than at less stressful times. amino acids Building blocks of protein normally used to build tissues or, under some conditions, burned for energy 6

Energy from Nutrients Some substances, such as the toxin alcohol, provide calories but are not nutrients. toxin poison calorie A unit used to measure energy 7

Vitamins and minerals are measured in grams or milligrams. Energy from Nutrients Vitamins and minerals are measured in grams or milligrams. gram A unit of weight, about 1/28th of an ounce 8

Energy from Nutrients Alcohol can contribute to fat because it provides calories but it does not promote growth, maintenance, or repair of the body. If you consume more carbohydrate, fat, and protein than you need, these nutrients will be stored in your body, mostly as fat. 9

Energy from Food The best source of energy for the body is a balanced diet. 10

Energy from Food For sufficient energy, eat a meal balanced with the right amounts of carbohydrates, fat, and protein. Fat helps with digestion while the carbohydrates and protein provide the body with lasting energy. digestion The breaking down of food into nutrients the body can use 11

Section Review: Reviewing the Vocabulary Define digestion. digestion The breaking down of food into nutrients the body can use

Section Review: Reviewing the Vocabulary What are calories? calories A unit used to measure energy