- Why this conversation matters in early CKD
- Most online “renal diet” advice is actually for more advanced kidney disease
- In early CKD, diet should usually focus on heart-healthy eating
- Potassium is not the villain for most people with early CKD
- Ultra-processed foods should be limited and replaced with more whole foods
- Be cautious with high-protein diets
- So what should you focus on?
- Final thoughts
Many people with CKD Stage 3 or 4 tell us the same thing:
“I was told I had kidney disease by my GP… but not really what to do about my diet.”
Sometimes they find out in a consultation. Sometimes it is through the NHS App, a letter, or blood test results that are mentioned almost in passing. Then, when they do ask what they should eat, they are often told something vague like, “Just eat normally and cut down on salt.”
So what happens next?
Quite often, people turn to Dr Google.
And that is where things can quickly become overwhelming. One search leads to another, and before long, they are looking at long “renal diet” food lists that make it seem like everything is off limits. Or that one list says one thing and the other list says the complete opposite!
If that sounds familiar, you’re not alone.
This is exactly why we recently agreed to speak about diet with CKD Stage 3-4 on a podcast for healthcare professionals, including GPs in the UK, about how (mainly) GP practices can better support people with CKD Stages 3–4 through diet, especially when specialist kidney dietetic services are often not available at this stage.
That conversation may have been aimed at GPs, but it matters just as much for you.
Because if these are the messages healthcare professionals need to hear, they are also the messages people living with CKD deserve to hear clearly and early.
At KidneyWise, it is important to us not just to support people living with CKD directly, but also to improve the advice being shared more widely. Educating GPs and other healthcare professionals is part of our wider mission to help improve support for people with early CKD.
In this post, we are sharing the 5 key points we wish every GP would tell people with a new diagnosis of CKD.
Why this conversation matters in early CKD
One of the biggest problems in early CKD is that many people are not referred to a specialist kidney dietitian early enough. Not because it’s not important, but because there are limited resources in dietetics (and the NHS more widely), so they are usually saved for more advanced cases of CKD.
That leaves a lot of people stuck in a frustrating middle ground.
On one side, there is very vague advice like, “Just eat normally.”
On the other hand, there is strict online advice that is often designed for people with much more advanced kidney disease.
The result is usually the same: fear, confusion, and often unnecessary restriction.
Diet does matter in early CKD, and it can make a difference. But the advice needs to be stage-specific, evidence-based and practical. It should help you feel clearer and more confident, not frightened.
Here are the 5 things we wish every GP would tell people early on.
Most online “renal diet” advice is actually for more advanced kidney disease
This is one of the biggest sources of confusion.
A lot of the advice people find online is aimed at those with later-stage CKD or even people on dialysis, not those with Stage 3 or 4 CKD who are still in the earlier phases of managing their condition.
The term “renal diet” is often used far too broadly online. Many websites, forums and social media posts do not make it clear who the advice is actually for. Furthermore, some of the advice is outdated or not written by a specialist healthcare professional.
That means people with Stage 3–4 CKD often end up cutting out foods unnecessarily or “just in case”, even when there is no clear reason to do so.
This can look like:
- Avoiding bananas or tomatoes because they have heard potassium is “bad”
- Cutting out milk because they are worried about phosphate levels
- Choosing white bread over wholegrain bread because they have heard it is better for their kidneys
Blanket restrictions often do more harm than good. They can reduce variety in your diet, make meals feel stressful, and increase anxiety around food.
The truth is, not every person with CKD needs the same diet.
What matters is your stage of CKD, your blood results, your medications, and your overall health.
In early CKD, diet should usually focus on heart-healthy eating
For most people with CKD Stages 3–4, the best starting point is not a long list of foods to avoid.
It is a way of eating that supports both kidney health and heart health.
This matters because the kidneys and the heart are closely linked. People with CKD have a higher risk of developing cardiovascular disease (a condition affecting the heart and blood vessels).
When you have CKD, looking after things like blood pressure, blood sugar levels and cholesterol becomes especially important. A helpful eating pattern to support these three includes:
- Plenty of fruit and vegetables
- Wholegrains
- Beans, lentils and other plant foods
- Healthier fats such as olive oil, nuts and seeds
- Moderate portions of protein
- Less salt
- Fewer ultra processed foods
This way of eating helps support your overall health, not just your kidneys.
And importantly, it gives you something more useful to focus on than restriction.
Instead of asking, “What can’t I eat?”, it can be much more helpful to ask:
“What can I add more of to support my kidneys and heart?”
That simple shift can make a big difference. It moves the focus away from fear and towards building a diet that feels nourishing, realistic and sustainable.
Potassium is not the villain for most people with early CKD
Potassium is often the nutrient people panic about first.
But a low potassium diet is not usually necessary.
People tell us they have stopped eating bananas, tomatoes, potatoes, avocados, spinach, or other fruits and vegetables because they were worried these foods might harm their kidneys.
But for most people with CKD Stage 2–3, and many with Stage 3–4, potassium restriction is not routinely needed unless:
- Blood potassium levels are high
- Certain medications mean potassium needs closer monitoring
- Their healthcare team has specifically advised them to reduce it
This is important because unnecessarily cutting back on potassium-rich foods can mean eating fewer fruits and vegetables overall, which may actually make the diet less supportive for both heart and kidney health, not to mention overall health.
Potassium advice should be based on:
- Your blood test results
- Your medications
- Your kidney function trends
- Your individual clinical picture
Potassium advice should NOT be based on: fear or something you have read online that may not apply to you.
So if you have been avoiding lots of nutritious foods “just in case”, it may be worth getting proper advice before cutting them out.
Ultra-processed foods should be limited and replaced with more whole foods
When we think about what may be more harmful in early CKD, the bigger dietary concern is often not whole foods like fruit, vegetables or pulses. It is often the regular intake of ultra-processed foods, which tend to be high in salt, sugar, additives and poor-quality fats.
These foods can make it harder to manage blood pressure, blood sugar and overall metabolic health, all of which matter in CKD.
That said, not all processed foods are equal.
There is a big difference between:
- Minimally processed foods, such as oats, frozen vegetables, plain yoghurt, tinned beans, wholegrain bread or peanut butter
and - Ultra-processed foods, such as crisps, sugary breakfast cereals, processed meats, instant noodles, fizzy drinks, packaged cakes, and ready meals
Minimally processed foods can still absolutely have a place in a practical, kidney-friendly diet.
The aim is not perfection.
The aim is to reduce ultra-processed foods where possible and replace more of them with nourishing whole or minimally processed foods.
Some simple swaps could include:
- Crisps → unsalted nuts
Processed meats → chicken, fish, eggs, tofu, beans or lentils - Sugary cereals → porridge or a lower sugar wholegrain cereal
- Takeaway or ready meal → a simple homemade meal
Small swaps like these can make a meaningful difference over time.
Be cautious with high-protein diets
High-protein eating is heavily promoted online at the moment.
And to be fair, it can sometimes be helpful in specific situations. But for most people with CKD Stages 3–4, it is not usually the right direction.
Extra protein is not usually better when you have CKD.
Protein shakes, protein bars, protein supplements and high-protein diets such as keto diets may put unnecessary strain on the kidneys and should usually be avoided unless you have been specifically advised to use them.
For most people with CKD, a more moderate protein intake is appropriate.
In fact, many people in the UK already eat more protein than they actually need, so reducing protein intake a little is often necessary when diagnosed with CKD.
It can also help to shift the balance of your protein sources. Eating a more plant-based diet including plant-based proteins such as beans, lentils, chickpeas, tofu and soya foods can be useful, partly because they tend to contain less protein per gram than many animal-based sources and can support a more balanced eating pattern overall. If you do eat animal protein, aim for small portions and ideally no more than once per day.
This does not mean cutting out protein completely. It means aiming for the right amount, and often improving the balance of where that protein comes from.
So what should you focus on?
Try to focus on these key points:
- Be cautious with generic online “renal diet” advice
- Focus on an overall heart-healthy eating pattern
- Do not cut out potassium unless you have been told to do so
- Dial down on eating ultra-processed foods
- Avoid jumping on high-protein trends
- Moderate your protein intake rather than adding more
- Base decisions on your blood results, stage of CKD and individual advice
You do not need to fix everything at once. Small, realistic changes count. And in many cases, those small changes are the ones that are easiest to stick with long-term.
Final thoughts
If you have been feeling confused about what to eat with CKD, we hope this has helped cut through some of the noise.
You deserve advice that is clear, practical and tailored to your stage of kidney disease.
Not frightening. Not conflicting. And not designed for someone at a completely different stage of CKD.
That is the message we wanted GPs to hear in the podcast. And it is the message we want you to hear, too.
If you have CKD Stage 3 or 4, getting the right support with your diet early can make a real difference.
Many people are told they do not need to think about diet until their kidney disease becomes more advanced. But in reality, simple, personalised changes can be really helpful in supporting you to make long-term dietary changes that are kinder to your kidneys.
At KidneyWise, we support people with CKD Stages 3–4 with practical, personalised advice designed to help you feel clearer, calmer and more confident about food.
If you would like personalised support, you can book a free 15-minute enquiry call with an experienced kidney dietitian to explore how private 1:1 support can help you.
Disclaimer: This advice is primarily for individuals with CKD Stages 3 and 4. It is for educational purposes only and provides general advice. It is not a substitute for seeing a registered dietitian or another qualified healthcare professional.
