If you’ve ever Googled “what to eat on a kidney diet,” chances are you’ve been bombarded with information about low potassium diets. Suddenly, you’re faced with a long list of foods to avoid—many of which you thought were good for you. It’s overwhelming and confusing, and you don’t even know if this applies to you.
With so much conflicting advice online, it’s hard to know what’s right for you. But don’t worry—we’re here to break it all down in a simple, practical way. In this blog, you’ll learn:
✔ What causes high potassium levels in Chronic Kidney Disease (CKD)
✔ How high potassium is treated (both short- and long-term), including a low potassium diet
✔ Whether you actually need to follow a low-potassium diet—spoiler: not everyone does!
✔ Practical steps to lower potassium if needed—without feeling deprived.
By the end, you’ll have a clear action plan and the confidence to make the right food choices for your kidneys. Let’s get started!
What is potassium & why does it matter?
Potassium is an essential mineral that plays a big role in your body’s health. It helps:
- Keep your heart beating steadily
- Support muscle and nerve function
- Maintain fluid balance
When your kidneys are healthy, they regulate potassium levels by removing any excess through urine. In CKD, however, the kidneys don’t filter potassium as efficiently, which can lead to a buildup in the blood—this is called hyperkalemia.
Potassium is measured through a blood test, and normal levels typically range between:
🔹 3.5 – 5.3 mmol/L (millimoles per liter)
For people with CKD, doctors often recommend keeping potassium below 5.0 mmol/L to prevent complications. Levels above 5.3 mmol/L are considered raised, and anything above 6.0 mmol/L can be dangerous and may require urgent medical attention.
Symptoms of high potassium
When potassium levels rise too high, it can disrupt your heart’s rhythm and, in severe cases, even lead to a heart attack. Other symptoms can include:
✅ Muscle weakness
✅ Numbness or tingling
✅ Fatigue
✅ Nausea
One tricky thing about high potassium is that symptoms don’t usually appear until levels are dangerously high. That’s why regular blood tests are so important if you have CKD, in particular, more advanced levels of CKD.
What causes high potassium?
There are several reasons why potassium can build up in your blood:
- Reduced kidney function: As already mentioned, as CKD progresses, your kidneys can’t filter out potassium as well, leading to higher levels.
- Certain medications: If you are on any of the following medications, your healthcare team may monitor your potassium levels closely as they can cause an increase in potassium levels:
💊 Some blood pressure medications e.g. Ramipril, Lisinopril, Losartan, Valsartan. Even though these medications may cause potassium levels to increase, they are often the optimal drug for the treatment of high blood pressure and preserving kidney function in people with CKD.
💊 Diuretics (water tablets), in particularSpironolactone.
💊 Pain medication e.g. Ibuprofen as this can reduce kidney function.
💊A medicine that protects the heart and kidneys in particular Finerenone
- Poorly controlled blood sugars: If blood sugar levels are too high, potassium levels can rise.
- Blood test issues: Sometimes, a high potassium result is due to an issue with the blood sample, not your actual levels. A repeat sample may be requested if this is suspected.
- Dehydration: When you’re dehydrated, your kidneys hold on to more potassium instead of flushing it out through urine, so keep yourself hydrated.
- Constipation: Potassium is also removed through bowel movements, so constipation can cause levels to rise. Eating fibre and keeping hydrated can improve constipation.
- Acidosis: Too much acid in your blood causes potassium levels to increase. You can tell if you have acidosis by checking if you have low bicarbonate levels in your blood (sometimes written as HCO3)
- Blood transfusions: Your potassium levels may be checked after any blood transfusion.
- A high-potassium diet: If your kidney function is declining, eating too many potassium rich foods can contribute to raised levels.
How is a high potassium treated?
Treatment depends on how high your potassium levels are and whether it’s an emergency.
Emergency treatment (Potassium above 6.0 mmol/L)
If potassium levels are dangerously high and/or you have symptoms like irregular heartbeat, muscle weakness, or numbness, immediate treatment in a hospital is usually needed and may include:
✔ Intravenous calcium gluconate: to protect the heart
✔ Intravenous insulin & glucose: to help lower potassium quickly
✔ Nebulised salbutamol: via a face mask or T-tube piece in your nostrils
✔ Dialysis: if kidney function is severely impaired
Emergency treatment quickly lowers potassium, but it’s a temporary fix. You’ll still need a long-term management plan to prevent it from happening again.
Long-term management (Potassium above 5.0 mmol/L)
For ongoing high potassium, doctors may recommend:
✔ Diuretics: to help flush out potassium
✔ Sodium bicarbonate: if potassium is high due to too much acid in the blood
✔ Potassium binders e.g. Lokelma: bind to potassium in the gut
✔ A low-potassium diet: if needed. A specialist kidney dietitian can support you with this.
Does everyone with CKD Stages 3 and 4 need a low potassium diet?
The short answer? No, not everyone with CKD Stage 3 or 4 needs to follow a low-potassium diet.
If your kidneys can still manage potassium levels well, there’s no need to cut back, and unnecessarily restricting potassium could even limit your intake of healthy foods.
You may need to limit high-potassium foods if:
- Your blood tests show raised potassium levels (above 5.3 mmol/L)
- You take medications that raise potassium levels
- Your doctor, nurse or dietitian has advised you to reduce potassium
If your potassium levels are normal, there’s no need to restrict potassium unless advised by your healthcare team.
Before changing your diet, we recommend:
- Discuss your potassium levels with your healthcare team and whether a low-potassium diet is needed
- Look at all possible causes, not just your diet and take any other necessary steps
- Enquire if you can work with a specialist kidney dietitian if you need to follow a low potassium diet to find the right balance—cutting out potassium completely is unnecessary and could limit healthy food choices.
We get asked a lot about potassium in our 1:1 consultations. If you would like to know more about whether you need to reduce potassium in your diet and how you can best do that for kidney health, why not book a FREE 15 minute enquiry call to chat with a kidney specialist dietitian to see how 1:1 support can help you.
10 steps for a low potassium diet
If you have been advised to follow a low potassium diet, we recommend working with a specialist kidney dietitian if you can. If you are unable to, here are a few tips to get you started:
- Avoid foods with potassium additives: Check food labels for ingredients like potassium chloride, potassium sorbate, potassium nitrate, potassium citrate, potassium phosphate and potassium lactate. Potassium additives are most commonly found in processed foods eg crisps & savoury snacks, salt substitutes and some canned goods.
- Choose low potassium fruits: Fruit does not and should not be excluded if you are on a low potassium diet. Instead opt for low potassium fruit such as apples, blueberries, peaches, clementines and pears (80g portion size).
- Choose low potassium vegetables: Like fruit, vegetables should also not be excluded on a low potassium diet. Choose low potassium options such as green beans, cauliflower, courgettes, carrots, cucumber and peppers (80g portion size).
- Choose low potassium starchy carbohydrates: Pick rice, pasta, noodles, oats and couscous over potatoes, sweet potatoes, quinoa and bulgur to keep potassium levels in check.
- Swap animal protein with plant protein: Replace higher potassium meats like beef with plant-based options like tofu, beans or lentils.
- Use low potassium cooking methods: Boil potatoes and vegetables before cooking and discard the cooking water to reduce potassium content, rather than roasting or steaming.
- Choose lower potassium snacks: Stick to popcorn, rice cakes, tortilla chips, plain biscuits, sponge cake instead of chocolate bars, potato crisps, Bombay Mix or fruit cake.
- Choose lower potassium drinks: Stick to water, tea, infused water, sugar-free fizzy drinks and squash instead of coffee, drinking chocolate, fruit juices and smoothies. Read our blog post about what people with kidney disease can drink besides water for further information.
- Pair higher-potassium foods with low-potassium options: Balance your plate by mixing a small portion of a high-potassium food with low-potassium sides. For example, if you have a tomato-based sauce, pair it with pasta and a low potassium vegetable instead of potatoes and a high-potassium vegetable.
- Practice portion control: If including high potassium foods occasionally, keep an eye on serving sizes to avoid excess potassium.
Low potassium recipes
Try to experiment with low potassium recipes to find meals that you enjoy so you don’t feel restricted. Here are a few simple low potassium recipes to get you started:
Lemon & Herb Chicken with Rice and Green Beans
Serves 2 | Prep & Cook Time: 45 minutes (includes 30 minutes marinating time)
Ingredients:
- 2 small chicken breasts (or 1 large, split)
- 1 tbsp olive oil
- 1 tbsp lemon juice
- 1 tsp dried oregano
- ½ tsp garlic powder
- 1 cup cooked rice
- 1 cup green beans, trimmed
Instructions:
- In a bowl, mix olive oil, lemon juice, oregano, garlic powder, and black pepper. Coat the chicken and let it marinate for 30 minutes at least.
- Heat a pan over medium heat and cook the chicken for 5–6 minutes per side, until fully cooked.
- While the chicken cooks, steam the green beans for 5 minutes until tender.
- Serve the chicken with rice and green beans.
Creamy Garlic Pasta with Courgette & Peppers
Serves 2 | Prep & Cook Time: 25 minutes
Ingredients:
- 150g pasta
- 1 tbsp olive oil
- ½ small onion, finely chopped
- 1 cup mixed peppers, sliced
- 1 small courgette, sliced
- 1 garlic clove, minced
- ½ cup unsweetened almond milk
- 2 tbsp cream cheese
- Black pepper & dried basil to taste
Instructions:
- Cook the pasta according to packet instructions. Drain and set aside.
- Heat olive oil in a pan over medium heat, then sauté onions, mixed peppers, and courgette for 5 minutes.
- Add garlic and cook for another minute.
- Pour in oat/almond milk or dairy milk and stir in cream cheese until smooth. Simmer for 2 minutes.
- Toss in the cooked pasta, season with black pepper and basil, then serve warm.
Tofu & Veggie Stir Fry with Noodles
Serves 2 | Prep & Cook Time: 20 minutes
Ingredients:
- 200g firm tofu, cubed
- 1 tbsp sesame oil
- ½ small red bell pepper, sliced
- 1 cup cabbage, shredded
- ½ cup courgette, sliced
- 1 tbsp reduced-salt soy sauce
- ½ tsp ginger (grated or powdered)
- 1 tsp honey (or maple syrup)
- 150g rice noodles, uncooked
Instructions:
- Heat sesame oil in a pan and lightly fry tofu cubes until golden. Remove and set aside.
- In the same pan, stir-fry bell pepper, cabbage and courgette for 5 minutes.
- Add soy sauce, ginger, and honey, then return the tofu to the pan.
- Toss with cooked rice noodles, stir well, and serve.
Can I have a meal plan to reduce my potassium?
If you’ve been told to follow a low potassium diet, it’s natural to wonder whether you need a strict meal plan to keep things under control. The truth is, a meal plan isn’t always necessary for everyone. Many people successfully manage their potassium levels by learning which foods to limit, how to adjust portion sizes, and making simple swaps in their everyday meals.
However, there are times when a structured meal plan can be really helpful, especially if:
- You’re feeling overwhelmed and don’t know where to start.
- Your blood potassium levels have been persistently high despite trying to make changes.
- You’re struggling to balance a low potassium diet with other dietary needs, such as diabetes or heart health.
- You want reassurance that you’re meeting your nutritional needs while keeping potassium in check.
If this sounds like you, our 7-Day Meal Plan for CKD Stage 4 could be just what you need. It takes the guesswork out of meal planning and provides balanced, kidney-friendly recipes that are naturally lower in potassium, salt, phosphate and protein. It is also suitable if you have CKD Stage 3 and have been advised to follow a low potassium diet.
Key takeaways
If you have CKD, potassium is something to be mindful of but not everyone needs a low potassium diet. The key is to monitor your levels, understand the root cause of high potassium, and make dietary changes if needed—with the support of your healthcare team.
Need more guidance? A specialist kidney dietitian can help you personalise your diet while keeping it enjoyable and balanced. You don’t have to do this alone! Book a free 15-minute enquiry call to chat with a kidney specialist dietitian to see how 1:1 support can help you.
Disclaimer: This advice is primarily for individuals with CKD Stages 3 & 4. It is solely educational and provides general advice only. It is not a substitute for seeing a registered dietitian or another qualified healthcare professional.
