'A diet rich in protein and fat promotes fluid loss. (Urea, a byproduct of protein, is a well-known diuretic.) Instead, try consuming more foods that are rich in complex carbohydrates. Beans, legumes, and whole grains absorb and retain water. '

According to Dr. David williams on his article dehydration a hidden cause of joint pain  he adds that eating high protein foods can add to this:
''A diet rich in protein and fat promotes fluid loss. (Urea, a byproduct of protein, is a well-known diuretic.) Instead, try consuming more foods that are rich in complex carbohydrates. Beans, legumes, and whole grains absorb and retain water. Pretty much any high-fiber food will help tremendously, including vegetables (particularly raw), whole fruits (the pectin content in apples makes them especially helpful), and sprouted seeds. As they move through the intestinal tract, they provide a “reservoir” from which the body can pull water as it is needed. By the time most foods reach the large intestine, about the only thing being absorbed at that point is water. ''

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