Potatoes are a much-loved part of meals here in the UK – from a comforting roast dinner to creamy mash, crispy chips, or a jacket potato with your favourite filling. So, it can feel confusing and even frustrating when you’re told to avoid them after a kidney disease diagnosis, or when you read online that you need to double-boil them or cut them out altogether.
We hear this a lot: potatoes are often one of the first foods mentioned by healthcare teams, sometimes without a clear explanation, and the conflicting information on the internet doesn’t make it any easier. You might be wondering – are potatoes bad for kidney disease? Do I really need to give them up completely? Or is there a way to still enjoy them safely?
The good news is you don’t necessarily need to cut potatoes out completely. With the right preparation and portion sizes, they can still fit into a kidney-friendly diet.
In this post, we’ll break down:
- The nutrients in potatoes and what they mean for kidney health,
- Why potassium is a concern (and whether it applies to you),
- How different types of potatoes and potato products compare
- The best preparation methods if you need to follow a low potassium diet
- Practical tips to help you still enjoy potatoes without feeling deprived.
By the end, you’ll feel clearer, more confident, and reassured that you can still include potatoes in your meals – in a way that supports both your kidney health and your love of good food.
Nutrients in potatoes
Potatoes are often seen as a comfort food, but they also provide important nutrients. Understanding what’s in them can help you see how they might fit into your kidney-friendly diet.
Here’s a simple breakdown of raw potatoes:
- Protein: Low
- Fat and saturated fat: Low
- Carbohydrate: High – potatoes are a starchy food, so they provide energy. There is more starch in white potatoes than in sweet potatoes.
- Fibre: Moderate (higher if the skin is eaten) – supports digestion and can help with blood sugar control.
- Sodium (salt): Naturally low – but watch out for added salt in processed potato products such as potato waffles.
- Potassium: High – higher in white potatoes than sweet potatoes, though it is still high. It can accumulate in the blood if kidney function is reduced. So how much potassium is in potatoes? An average portion size of about 200g, equivalent to 1 small to medium-sized raw potato (fist-sized), contains around 900mg of potassium. This is more than in bananas.
- Vitamins:
- Vitamin C: supports the immune system and helps with iron absorption
- Vitamin A: mainly in sweet potatoes, is important for vision and skin health
Why exactly are potatoes such a focus in kidney disease? Let’s look at the main reason they often come up in conversations about CKD (spoiler alert: it’s their potassium content), and what that means for you.
Potatoes & CKD - what's the concern?
The main reason they often get highlighted in kidney disease is that potatoes are high in potassium.
When kidney function is reduced, your kidneys may not be able to remove extra potassium from your blood as well as before. This can cause high potassium levels. If your blood tests show high potassium, your healthcare team may recommend following a low potassium diet, which often includes limiting potatoes.
Here’s something important: not everyone with CKD needs to limit potassium. Your blood results are yourbest guide, so check with your doctor or dietitian before making big changes.
Even if you don’t need a low-potassium diet, there are still reasons to think about how you include potatoes:
- Healthy eating balance: Potatoes are low in fat and salt naturally, but fried options (chips, roasties) or processed products (frozen potato products and instant mash) can add a lot of extra fat, salt, and calories.
- Diabetes and CKD: If you also have diabetes, white potatoes can cause sharper rises in blood sugar. In this case, swapping or mixing with sweet potatoes (which release energy more slowly) may be a better choice – though the potassium content still matters.
- Gut health: The temperature of the potatoes you eat can have an impact on your gut health. Cooling potatoes after cooking and eating them chilled eg potato salad, or even reheating increases the resistant starch. This works as a prebiotic, feeding the friendly bacteria in your gut.
Now let’s look at the different types of potatoes in more detail – from fresh to frozen to instant mash – and how each one fits into a kidney-friendly diet.
If you would like support with a kidney-friendly diet, why not book a FREE 15-minute enquiry call with an experienced kidney dietitian, to find out how 1:1 support could help you.
Kidney-friendly potatoes
Not all potatoes are the same, and the way they’re prepared can make a big difference to their nutritional content. Here’s a breakdown of the most common types:
Fresh potatoes (white or sweet)
- This is the best option if you want full control over how they’re prepared.
- Aim for a portion size of 150-200g or 1 medium-sized potato (fist-sized).
- Can be boiled, mashed, roasted, baked, fried, or air-fried and cooking methods are key to managing potassium and overall health.
- Use low potassium cooking methods to remove potassium (more on that later!) if you are on a low potassium diet.
- Choose cooking methods such as boiling or air frying to limit fat intake.
- Consider eating potatoes chilled eg potato salad, or reheating leftovers to increase the resistant starch for optimal gut health.
Frozen potato products (chips, wedges, roasties)
- Higher in salt compared to fresh potatoes
- Some versions (like triple-cooked chips) can be particularly high in fat. Lighter or “oven-baked” versions may be better, but always check labels
- Can use low potassium cooking methods to remove some potassium (more on that next!)
Tinned potatoes
- Convenient but may be higher in salt
- Can use low potassium cooking methods to remove some potassium (more on that next!)
Instant mashed potato
- Lower in fibre compared to fresh.
- High in potassium and not possible to remove potassium, so best avoided if you are following a low potassium diet.
- Contains phosphate additives.
Potato-containing ready meals
- Nutrient content can vary a lot depending on the meal, but often high in fat and salt.
- Better to prepare fresh meals where possible and limit these ready meals where possible.
👉 The bottom line: fresh potatoes (white or sweet) are usually the better choice, as you can decide how to prepare them, control the portion, and use kidney-friendly cooking methods.
Low potassium diets and potatoes
If your blood results show a high potassium and/or you’ve been advised to follow a low potassium diet, you don’t have to cut potatoes out completely – but what you choose, how you prepare them and how you portion them really matter.
Here are some key tips to make potatoes safer for a low potassium diet:
Best to Avoid
- Instant mashed potato: very high in potassium and best avoided.
- Potatoes in ready meals: you can’t control how they’re cooked, and they often contain extra salt and fat. If you need to rely on ready meals, choose those that are lower in salt and rice or pasta-based.
Safer Options (with the right preparation)
- Fresh potatoes (white or sweet): choose fresh when eating potatoes. Limit portion size to 150-200g or 1 small to medium-sized potato (fist-sized). Use our kidney-friendly preparation method below.
- Tinned potatoes: can be used occasionally if soaked before cooking. Soaking for 12 hours reduces the potassium by around 78%.
- Frozen potatoes: can be used occasionally, and it is recommended to be soaked before cooking. Soaking for 12 hours reduces the potassium by around 88%.
Low potassium cooking methods for potatoes
Here is our recommended cooking method for preparing low-potassium potatoes if you are on a low-potassium diet. It shows you exactly how to leach potassium from potatoes in the most kidney-friendly way!
1. Peel your potatoes
2. Cut potatoes: cut into small pieces (strips, cubes, or slices). Smaller pieces increase the surface area, allowing more potassium to leach out when put into water
3. Boil in a large volume of water: use a big pan filled with plenty of water. Potassium moves from the potato into the cooking water. Strip cut or dice cut removes around 35-37% of potassium.
4. Drain and discard the cooking water: never reuse it in gravy, soups, or stews.
5. Soak after cooking (optional): soaking in warm water for a short time before serving can removes more potassium. Strip-cut potatoes boiled for 8 minutes, then soaked for 12 hours, removes 90% of potassium. Dice-cut potatoes boiled for 8 minutes, then soaked for 12 hours, removes 73% of potassium.
6. Cooking styles after boiling
- Once boiled, you can mash, roast, fry, or air-fry. Note that frying will increase the potassium slightly due to loss of moisture.
- Limit the amount of fat added and use healthy fats such as rapeseed oil or olive oil.
What You Don’t Need to Do
- No need to double-boil (boil twice): Previous advice has been to boil twice, but more recent research has shown that this doesn’t make as much difference as previously thought, and one good boil in a large pan of water is enough.
- No need to pre-soak raw potatoes: pre-soaking raw potatoes before cooking only reduces potassium by about 16% so it’s better to focus on other methods that remove more potassium.
Practical tips to include potatoes in a kidney-friendly diet
- Choose fresh over frozen or processed: this gives you more control over how they’re prepared.
- Watch portion size: aim for about 150-200g raw potato (around one small to medium potato or a fist-sized portion).
- Limit frequency: if you’re on a low potassium diet, enjoy potatoes a couple of times a week rather than daily, with the remaining week choosing wholegrain carbohydrates such as brown rice, buckwheat, and whole wheat pasta.
- Mix with alternatives when making mash: try half potato and half cauliflower, swede or carrots.
- Alternate with sweet potatoes: if you also have diabetes, this may help with blood sugar control – but you still need portion control and kidney-friendly cooking methods.
- Pair wisely: serve potatoes alongside low-potassium vegetables (e.g., green beans, carrots, cabbage) to balance your plate.
- Use kidney-friendly cooking methods: boil potatoes first, then soak, followed by your preferred cooking method, such as mash, roast, or air fry.
- Avoid added salt: flavour with herbs, spices, garlic (fresh or granules), or a drizzle of olive oil instead.
These small tweaks mean you don’t have to feel deprived – you can still enjoy potatoes while protecting your kidney health.
Frequently asked questions
❓ Can I eat chips from the chippy?
If you’re not on a low potassium diet: Yes, as an occasional treat. Ask for no added salt and share a portion rather than having a whole one to yourself. If you’re on a low potassium diet: A few chips are usually okay, but avoid making it a regular choice.
❓ Are sweet potatoes better than white potatoes?
Not necessarily. Sweet potatoes are higher in vitamin A and can sometimes be better for blood sugar control if you also have diabetes. However, they still contain a lot of potassium, so portion size and preparation are just as important as with white potatoes.
❓ Can I still eat roast potatoes at Christmas?
Yes! You don’t have to miss out. Prepare them by peeling, cutting, and boiling first to lower the potassium, then roast in a small amount of healthy fat (like olive oil or rapeseed oil). Moderate your portion size and balance it with other lower potassium veggies.
❓ Should I avoid potatoes completely if my potassium is high?
Not usually. Even with high potassium, you may still be able to enjoy small amounts of potatoes occasionally prepared in a kidney-friendly way.
Key takeaways
✅ Potatoes don’t need to disappear from your diet if you have CKD.
✅ Fresh potatoes are usually the best choice, giving you control over preparation and portion.
✅ If you’re on a low potassium diet, focus on portion size, frequency, and kidney-friendly cooking methods like boiling.
With the right approach, potatoes can still be part of enjoyable meals – so you don’t have to feel deprived or miss out on your favourites.
Want to feel more confident about your food choices?
Download our free guide CKD Results Made Simple, where we explain what your blood test results mean and how they connect to your diet.
👉 Download your free guide HERE
This blog is written for people with CKD Stages 3 and 4. It provides general education only and should not replace personalised advice. Always check your blood test results and speak to your doctor or a registered dietitian before making changes to your diet.
