Kidney disease: why there is no single 'kidney diet', and what to eat instead

The first thing many patients do after a diagnosis of chronic kidney disease is search for a "kidney diet". What they find is a list of forbidden foods: no bananas, no tomatoes, no daal, no meat, no milk, drink less water. By the time they reach my clinic they are frightened of food and often eating far too little.

So let me say the most important thing first. There is no single kidney diet. What is right for you depends on your stage of kidney disease, your blood results, your medicines, and whether you are on dialysis. The same advice can be unnecessary for one person and genuinely harmful for another.

What your kidneys do

Your kidneys filter waste and extra fluid out of your blood, and they keep minerals such as sodium, potassium and phosphorus in balance. When kidney function declines, often without obvious symptoms at first, those balances become harder to maintain. That is why nutrition matters so much in CKD, and why the advice has to follow your results rather than a generic list.

The five things that change

Salt (sodium). This is the one change that applies to nearly everyone with CKD. Less salt helps blood pressure, which protects the kidneys, and reduces fluid retention. Most of our salt comes from cooking salt, pickles, chutneys, papad, namkeen and packaged foods. Flavour with lemon, herbs and spices instead.

Protein. This is where the generic advice goes most wrong. If you have CKD and are not on dialysis, your team may advise a moderate protein intake, but not zero: too little protein causes muscle loss and malnutrition, which makes everything worse. If you are on dialysis, your protein needs usually go up, because the treatment removes some. The right amount is set from your results and your stage.

Potassium. Bananas, oranges, tomatoes, potatoes, daal and dry fruit are all rich in potassium. They are limited only if your blood potassium is high. Many people with CKD can and should keep eating fruit and vegetables. When a limit is needed, portions and cooking methods (such as boiling potatoes and discarding the water) usually matter more than banning whole food groups.

Phosphorus. As kidney function falls, phosphate can build up and damage bones and blood vessels. The biggest culprits are not natural foods but phosphate additives in processed foods and cold drinks. Reading labels for anything containing "phos" is often more useful than cutting dairy or daal.

Fluid. Most people with early CKD do not need to restrict fluids, and drinking too little can harm the kidneys. Fluid limits usually come later, or on dialysis, and they are set by your nephrologist.

Pakistani food and the kidneys

Our everyday diet is not a problem in itself. Daal, roti, sabzi, chicken, fish, dahi and rice can all fit into a kidney plan. What usually needs attention is the salt in cooking and achar, the phosphate in cold drinks and packaged snacks, and the portion of protein, in whichever direction your results require.

Fresh meals, thoughtful portions and less processed food help almost everyone. But please do not cut potassium-rich foods, protein or fluids on your own. Those decisions need your results and your team.

If you also have diabetes or high blood pressure

In Pakistan, these are the two most common causes of kidney disease, and most of my kidney patients have at least one. The plan has to balance all three: steady blood sugar, lower blood pressure and kidney-appropriate portions. It is more detailed, but it is very doable with the food you already cook.

What to bring to a consultation

Your most recent blood and urine results, especially eGFR, creatinine, potassium, phosphate, sodium, albumin and HbA1c, and your full medicine list. Bring whoever cooks at home too. Kidney nutrition changes as results change, so regular review matters, and I share the plan with your nephrologist if you wish.

Never change prescribed medicines or fluid limits without your nephrologist.

Sources

• NHS, Chronic kidney disease: living with
• NICE NG203, Chronic kidney disease: assessment and management
• KDIGO 2024, Clinical practice guideline for the evaluation and management of CKD
• National Kidney Foundation, Nutrition and kidney disease