1. Carbohydrates: These are the body's primary source of energy. They are made up of sugar molecules and can be found in foods like bread, pasta, rice, fruits, and vegetables.

2. Proteins: These are essential for building and repairing tissues, making enzymes and hormones, and transporting substances throughout the body. They are made up of amino acids and can be found in foods like meat, poultry, fish, beans, nuts, and dairy products.

3. Fats (Lipids): These are a concentrated source of energy and help the body absorb vitamins, insulate organs, and protect cells. They are made up of fatty acids and can be found in foods like oils, butter, cheese, and fatty meats.