Nutrition in Later-Stage CKD (Stages 3b–5)

Nutrition Becomes More Individual in Later CKD 

As CKD progresses into stages 3b–5, nutrition often becomes a little more complex - and for many people, more emotional too. Food choices that once felt straightforward can suddenly come with questions or conflicting advice, and it's completely understandable to feel anxious about getting it wrong or worried that eating is going to become restrictive and joyless.

The good news is that there is no single "renal diet" that works for everyone. Nutrition at stages 3b to 5 is highly individual, and with the right guidance it can remain flexible, supportive, and focused on keeping you feeling as well as possible.

Why Nutrition Needs to Change in CKD Stages 3b–5 

As kidney function declines in stages 3b to 5 of kidney disease, the kidneys become less efficient at filtering waste products, balancing electrolytes such as potassium and phosphate, and managing fluid levels. This can affect:

• How your body handles waste products, including urea from protein digestion
• Your electrolyte balance, which can shift up or down
• Your appetite and energy levels - many people notice tiredness, taste changes, or feeling full more quickly than usual

But these changes don't affect everyone in the same way. Your blood results, symptoms, medications, body size, activity level, and any other health conditions all play a part in shaping your nutritional needs. This is why personalised advice matters so much at this stage of kidney disease.

If you haven't already seen a renal specialist, you can ask your medical team for a referral. Or if you'd like to find a dietitian in private practice you can search for one on the BDA website.

Protein: Personalised targets, Not Eliminated 

Protein is often a source of confusion for people with CKD. Your protein needs may change as your kidney function declines, but protein is not automatically taken out of your diet.

The goal is to find the right balance between:

• Preserving your muscle strength and function
• Avoiding a build-up of waste products in the blood

For some people with CKD, modestly reducing protein intake can help manage symptoms or blood results. For others - particularly those who are frail, unwell, losing weight, or preparing for dialysis - getting enough protein is essential to maintain the strength needed for daily life.

This balance is best worked out with a renal dietitian, who can help you adjust your protein intake over time based on your kidney function, blood results, and overall health.

Potassium: Awareness  

Potassium is a mineral that helps keep your heart, muscles, and nerves working properly. In CKD, potassium levels in the blood can become too high or too low - both of which can be dangerous. However, not everyone with CKD needs to restrict potassium.

A simple blood test can measure your potassium levels. Normal blood potassium levels are 3.7- 5.5mmol/l. How much potassium you need will depend on:

• How well your kidneys are working 
• Whether you are taking medications that affect potassium levels

If you do need to reduce potassium in your diet, some practical options include:

• Avoiding potassium additives in foods 

• Reducing portion sizes of potassium rich foods

• Using cooking methods that can reduce potassium - for example, peeling, cutting, and double‑boiling potatoes can lower potassium by around half 

• Choosing lower‑potassium fruits and vegetables such as green beans, sweetcorn, cauliflower, celery, berries, and apples 

There is also emerging evidence that choosing higher-fibre fruits and vegetables may help prevent significant rises in blood potassium for some people.

Foods that tend to be higher in potassium include bananas, tomatoes, melons, potatoes, dried fruit, nuts, fruit and vegetable juices, milk, yoghurt, dried beans and peas, and protein-rich foods such as meat, fish, and poultry. Whether any of these need limiting depends entirely on your individual blood results - not on a blanket avoid list.

Phosphate: Protecting Your Bones and Blood Vessels 

Phosphate is a mineral that supports bone health. But as kidney function declines, phosphate can build up in the blood, increasing the risk of bone disease and damage to blood vessels.

It helps to understand the difference between two types of phosphate in food:

• Natural phosphate, found in foods like dairy, meat, fish, nuts, and pulses
• Phosphate additives, often hidden in processed foods - and more easily absorbed by the body

Reading ingredient labels for words beginning with "phos" can help you spot hidden phosphate in your diet. Evidence shows that cutting back on phosphate additives in particular can significantly lower phosphate levels in the blood. Rather than eliminating whole food groups, renal dietitians can help with practical swaps and portion control.

Calcium and phosphate are closely linked. Many good sources of calcium are also high in phosphate, and often the most effective way to protect your bones is to limit high-phosphate foods rather than simply increasing calcium intake. Some people may also need phosphate binders or a prescribed form of vitamin D - your renal team will guide you on this.

Salt and Fluid Balance with CKD

Reducing your salt intake can help

• control your blood pressure
• lower your risk of heart disease
• support fluid balance.

People with CKD are advised to reduce their saly intake to no more than 5–6g of salt per day.

Rather than using salt for flavour, try using herbs, spices, garlic, pepper, lemon and vinegars. Fluid restriction is only needed for some people, and is introduced based on symptoms and medical advice. If you are unsure whether you need to limit your fluid intake, speak to your renal team.

Eating Enough to Maintain Your Energy and Weight 

Reduced appetite, taste changes, and feeling full quickly are all common in later-stage CKD, and can lead to unplanned weight loss. Keeping on top of this can become an important priority.

Some strategies that can help maintain your energy with later stage CKD:

• Small, frequent meals can be easier to manage than three larger ones
• Nourishing snacks (your dietitian can help with ideas)
• Making and eating food that is familiar and enjoyable

It's worth remembering that nutrition isn't just about numbers - maintaining pleasure and quality of life around food matters too.

Nutrition Before Dialysis 

If you are approaching dialysis, good nutrition can help support your strength, healing, and resilience going into treatment. Extreme or overly restrictive diets are rarely helpful at this stage - there is no need to "save protein" or panic.

The aim is preparation, not perfection, and your dietitian will be able to help guide you through this transition.

How a Renal Dietitian can help You 

A renal dietitian can help by: 

• Setting personalised targets based on your individual needs
• Reviewing and adjusting advice as your blood results change over time
• Supporting your quality of life alongside your medical care

Your nutrition plan should change as your health does - but it should never feel punishing.

Take-Home Message

Nutrition in later-stage CKD is about support, not punishment. With the right guidance, food can remain pleasurable, nourishing, and meaningful - helping you live as well as possible at every stage of your kidney disease journey.