Quick Tip: High Protein Diets Can Cause Dehydration. Contrary to what you may have read, high-protein diets are not hard on your kidneysâassuming your kidneys are healthy in the first place. But they can be dehydrating. (Itâs not the same thing.) As a rule of thumb, concentrated urine is a sign that you might need to drink more water. If you increase your protein intake, increase your fluid intake as well to prevent dehydration. Remember that fruits, vegetables, soups, and dairy products are also good sources of water. For more on protein, see How Much Protein Should You Eat? For more on dehydration, see How Much Water Should I Drink?