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 more complex - and for many people, more emotional too. Food choices that once felt straightforward can suddenly come with questions, restrictions, or conflicting advice. 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 nutrition at later stages of CKD is highly individual. There is no single “renal diet” that works for everyone [1,2]. With the right guidance, nutrition can remain flexible, supportive, and focused around maintaining both your health and quality of life [1]. 

Why Nutrition Needs Change in CKD Stages 3b–5 

As kidney function declines, the kidneys become less efficient at filtering waste products, balancing electrolytes such as potassium and phosphate, and managing fluid levels [1]. These changes can affect: 

• Waste product handling, including urea from protein metabolism [1] 
• Electrolyte balance, which can shift in either direction [3] 
• Appetite and energy levels, with many people experiencing fatigue, taste changes, or early fullness [4] 

Importantly, these effects do not occur in the same way for everyone. Blood results, symptoms, medications, body size, activity level, and other medical conditions all influence nutritional needs [1,2]. This is why personalised advice is so important in later-stage CKD [2]. 

Protein: Individualised, Not Eliminated 

Protein is often a source of confusion. In CKD, protein needs may change, but protein is not automatically removed from the diet. 

The goal is to balance: 

• Preserving muscle strength and function 

• Avoiding excessive waste buildup 

For some people, a modestly adjusted protein intake may help manage symptoms or blood results [5]. For others - particularly those who are frail, unwell, losing weight, or preparing for dialysis - adequate protein is essential to maintain strength and resilience [2,6]. 

This balance is best guided by a renal dietitian, who can adjust protein intake over time as kidney function, blood results, and overall health change [1,2]. 

Potassium: Awareness  

Potassium is a mineral that helps keep the 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 — but not everyone with CKD needs to restrict potassium [3,7].  

A simple blood test shows 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 [7] 

Some options reduce potassium blood levels involve [7,8]: 

• Avoid potassium additives in foods  

• Reudcing Portion sizes  

• Cooking methods 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 emerging evidence that choosing higher‑fibre fruits and vegetables may help avoid significant rises in blood potassium for some people [8]. 

Foods higher in potassium include certain fruits and vegetables (bananas, tomatoes, melons, potatoes), dried fruit, nuts, fruit and vegetable juices, milk and yoghurt, dried beans and peas, potassium‑based salt substitutes, and protein‑rich foods such as meat, fish, and poultry. Whether these need limiting depends entirely on individual blood results — not on avoid‑lists alone [7,8]. 

Phosphate: Protecting Bones and Blood Vessels 

As kidney function declines, phosphate can build up in the blood, increasing the risk of bone disease and blood vessel calcification [9].  

It helps to understand the difference between: 

• Natural phosphate, found naturally in foods like dairy, meat, fish, nuts, and pulses 

• Phosphate additives, often hidden in processed foods and absorbed more easily by the body [9,10] 

Reading ingredient labels for words starting with “phos” can help reduce hidden phosphate intake. Evidence shows that reducing phosphate additives can significantly lower serum phosphate levels [10]. Rather than eliminating food groups, renal dietitians focus on practical swaps and portion control [1].  

Calcium and phosphate balance are closely linked. Many good sources of calcium are also high in phosphorus, and often the most effective way to protect bones is to limit high‑phosphorus foods rather than increasing calcium intake. Some people may need phosphate binders, avoid calcium‑fortified foods, or take a prescribed form of vitamin D. Decisions regarding phosphate binders, calcium intake, or vitamin D supplementation should be guided by a renal team [9]. 

Salt and Fluid Balance 

Reducing salt intake can help: 

• Control blood pressure 

• Lower cardiovascular risk 

• Support fluid balance [3] 

Flavour can be enhanced using herbs, spices, garlic, pepper, lemon and vinegars in replacement to adding salt. All people with CKD should aim to reduce their salt consumption.  

Fluid management is only needed for some people and is introduced based on symptoms and medical advice. If you are uncertain on whether you need to restrict your fluid intake, you should discuss this with your renal medical team.  

Maintaining Adequate Energy Intake 

Poor appetite, taste changes, and early satiety are common in later‑stage CKD. Preventing unintentional weight loss becomes a key priority [4]. 

Strategies may include: 

• Small, frequent meals 

• Nourishing snacks 

• Making food enjoyable and familiar 

Nutrition is not just about numbers — maintaining pleasure and quality of life is essential [1]. 

Nutrition Before Dialysis 

For those approaching dialysis, nutrition supports strength, healing, and resilience. Extreme or overly restrictive diets are rarely helpful [2]. There is no need to “save protein” or panic. Preparation, not perfection, is the aim and dietitians play a key role in guiding this transition [1,2].  

How a Renal Dietitian Supports You 

A renal dietitian helps by: 

• Setting personalised targets 

• Reviewing advice as blood results change 

• Supporting quality of life alongside medical care 

Nutrition plans evolve — they are not fixed or punitive. 

Summary 

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