Fat has gotten a bad rap, too, but it's one that's not entirely undeserved. "Bad" fats are associated with heart disease, some types of cancer, and some chronic illnesses. The right types of fat, however, are a concentrated source of energy. Saturated fat (found in foods like meat, butter, lard, and cream) and trans fat (found in baked goods, snack foods, fried foods, and margarines) have been shown to increase the risk for heart disease. Replacing saturated and trans fat in your diet with unsaturated fat (found in foods like olive oil, avocados, nuts, and canola oil) has been shown to decrease the risk of developing heart disease.
In order to strike the right balance, choose polyunsaturated fats such as vegetable oils and seafood and monounsaturated fats such as olive oil, nuts, and seeds. The unsaturated variety can help lower "bad" LDL cholesterol.
Fats and carbohydrates may supply the body with energy, but protein helps regulate the release of that power. Protein maintains cells, assists in growth, transports hormones and vitamins, and preserves lean muscle mass. Muscles and many hormones are, in fact, made up of protein. You need proteins for your immune system. So replenishing your body's source of the nutrient is very important.
Good sources of protein include meat, poultry, fish, eggs, beans, nuts, soy, and low-fat dairy products. When you eat these types of foods, your body breaks down the protein that they contain into amino acids (the building blocks of proteins). Some amino acids are essential, which means that you need to get them from your diet, and others are nonessential, which means that your body can make them.
In diets where the body does not get its usual fuel of carbohydrates and fat, protein provides the body energy.
The Weight of Water
Two-thirds of your body is made up of water. Without it, you could only live a few days. The fluid helps control body temperature through sweat, moves food through the intestines, and greases the joints. It's also an essential ingredient in the production of energy molecules.