The cost of food is escalating so quickly that a healthy diet becomes a financial as well as nutritional investment. To get the most from your foods, prepare them to retain the highest nutritional value. Proteins are most frequently cooked before consumption, so pay attention to what nutrients survive the microwave or the soup pot when you're making dinner.
Cooking doesn't affect the protein content in ground beef. The University of Wisconsin Extension says pan-frying or -broiling meat patties left the protein in the meat intact, but did provide a healthy benefit for high-fat meats. Cooking reduced the amount of fat in the meat by almost half, a significant benefit for those trying to lose weight or watch cholesterol intake. Lean meat lost a very small amount of fat during cooking, but both high-fat and lean meats kept all of their protein and iron.
Beans and Legumes
Some nutrients in beans and legumes leach into cooking water when they are boiled -- less so when they are steamed. To keep all the nutrients from veggie sources, use the least amount of water possible for cooking and save that water for soups or sauces. The soaking water that prepares beans for cooking, which contains moderate amounts of leached nutrients, should be discarded.
Seafood is an excellent protein source that is most often cooked before it is consumed. During cooking, the protein in the connective collagen "melts," so the fish flakes when it is done. The protein in the muscle coagulates and becomes opaque. When fish is cooked for a short time at a high temperature, it remains moist and tender, and the protein content is preserved. By overcooking fish and drying it out, some of the gelatinous collagen is lost, decreasing the amount of protein remaining in the dish. Shellfish are similarly quick-cooked -- when boiled, it takes moments for them to be done. The only caveat about seafood nutrition is a warning about mercury. The North Carolina Department of Health and Human Services says mercury bonds to the protein in fish and is not disturbed by cooking. Choose low-mercury fish to get your protein without harmful chemicals.
Eggs are a near-perfect protein source, and cooking them does little to alter that. The protein in egg changes shape when heated, but doesn't dissipate. Whites contain 10 percent protein – the rest is water – and the protein in egg whites breaks apart and reforms when exposed to heat. So a cooked egg white is no longer clear; it is coagulated and opaque. Too much cooking will force water from the protein bonds and give you rubbery, dry eggs, but no less protein. Even beating egg whites to make meringue just traps air in the protein bonds. When you let meringue sit for a while, it begins to turn back to liquid as the air escapes.
- University of Wisconsin Extension: Reducing Fat Levels in Ground Beef
- North Carolina Department of Health and Human Services: What Fish are Safe to Eat?
- Exploratorium: Science of Cooking: Cooking Fish with Finesse
- Exploratorium: Science of Cooking -- Do You Know How Hard to Cook an Egg?
- Oregon State University Extension; "Eggs…They Really Are Incredible"; January 2008