You'll need to get on what's called a 'Renal Diet'. You'll have to avoid any food high in potassium, as the kidneys are responsible for ridding the body of excess potassium, which is a crucial electrolyte responsible for proper heart functioning. Renal patients also aren't able to get rid of extra salt, so need to limit that.
Here's a site that explains the basics. A dietician could help with planning.
Not eating excessive Protein will help delay the next stage of kidney failure. Talking to a dietitian about how much Protein you can have is wise as well as learning about your levels so you know if you already have to limit other things such as Phosphorus and Potassium. It is wise to read up on what foods and drinks are high in these things but do not do anything you see online without consulting your Nephrologist (Kidney Doctor) or at least you Urologist. Family doctors don't always know specifics of what to do with kidney disease. Reading online will guide you to know what questions to ask. The reason why you need to limit Protein is because Protein is hard on a weak or failing kidney. But there have been studies that have said that you don't need to go with low Protein in some cases but just not eat excessive Protein. This is why it is important to seek the attention of your Nephrologist as soon as you can or at least a Renal Dietitian.
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