"DID YOU KNOW?: Eating a high-protein diet can cause dehydration if you don't drink a lot of water. Your body can use only so much protein each day. Any surplus must be converted into urea and excreted in the urine. The conversion requires a surprising amount of water, seven times what you'd need to metabolize the same number of calories in carbohydrates. That's why high-protein diets always call for extra fluids. It also explains why athletes on high-protein regimens are especially prone to water loss: they not only sweat a lot, but also give up water for protein extraction."