Meat in the hot seat
Cooking meat at high temperatures produces cancer-causing chemicals, but grilling can be made safer.
When we eat meat or fish, we're eating muscle tissue — mainly muscle cells, some collagen that makes up connective tissue (the more collagen, the tougher the meat), and fat. Cooking turns the tissue pleasantly firm and juicy by altering protein inside the muscle cells so it gets more compact and squeezes out water, according to On Food and Cooking, Harold McGee's classic book on food science.
But starting at between 140° and 150° F, the water gushes out, the proteins bunch up even further, and the tissue shrivels. What had been tender and juicy is on its way to becoming shoe leather.