高一英语必修3第2单元healthy eating课件2.ppt

Unit2 Healthy eating,Human beings need food to grow, and maintain(维持) good health. Eating the right foods can help us avoid some diseases or recover faster when illness occurs. These and other important functions功能 are provided by chemical substances in our food called nutrients. Nutrients are classified as,carbohydrate, protein, fat, vitamin, mineral, and water.,Carbohydrates are the human bodys key source of energy, providing 4 calories of energy per gram.,rice, noodles, sugar,bread potatoes,Chinese food has many variations, but most dishes are served with rice or noodles.,Proteins are powerful compounds that build and repair body tissues器官, from hair and fingernails指甲 to muscles. Besides maintaining the bodys structure, proteins speed up chemical reactions in the body. Although protein provides 4 calories of energy per gram, the body uses protein for energy only if carbohydrate and fat intake is insufficient.,Animal proteins, found in such food as eggs, milk, meat, fish, and poultry Plant proteins are found in vegetables, grains, and beans,Fats, which provide 9 calories of energy per gram, are the most concentrated集中 of the energy-producing nutrients, so our bodies need only very small amounts. Fats play an important role in building the membranes膜 that surround our cells and in helping blood to clot凝块. Once digested and absorbed, fats help the body absorb certain vitamins. Fat stored in the body can protects us from extreme cold.,Oil, cream, butter, nut,Vitamins and minerals not only help the body perform its various functions, but also prevent the onset of many disorders. For example, vitamin C is important in maintaining our bones and teeth.,Although such fibers provide no energy or building materials, they play an important role in our health. They help to flush the digestive tract消化道. Researchers claim it helps eliminate消除 cancer-causing chemicals and may decrease the amount of cholesterol in the blood stream.,The healthy diet pyramid,The food in Wang Pengweis restaurant provides more _ than