You might expect a renal cancer diagnosis to come with lots of diet restrictions, since damaged kidneys may allow fluid and waste to accumulate in the body and blood. But that’s not necessarily true. “We try to be liberal, not restrictive,” says Neha Shah, R.D., a clinical nutrition expert for cancer and kidney disease at Stanford Health Care in Palo Alto, CA. “We want patients to eat.” Proper nutrition can combat side effects of cancer treatment (like fatigue), keep blood pressure and blood sugar in check (vital for healthy kidneys), and maybe even aid treatment. But knowing what to eat can be tough.