Eating Well on Dialysis in the Tropics: A Practical Guide

Almost every renal diet sheet in existence was written for a temperate country. It will tell you about potatoes and bananas, and say nothing about breadfruit, cassava, coconut or the fish that is on the table most days of the week in Seychelles. This is an attempt to fix that. It is not a diet plan, and it cannot be one, because your numbers are yours.

There is no single kidney diet

The right diet depends on your modality, your remaining kidney function, your blood results, your other conditions, and what you actually eat. KDOQI's 2020 nutrition guideline deliberately moved potassium and phosphate advice away from blanket restriction and towards individualisation, which is a quiet admission that the photocopied "avoid these foods" list was never very good evidence.

And the message that gets lost: malnutrition harms more people on dialysis than one high-potassium meal does. Protein-energy wasting is common, dangerous, and strongly linked to poor outcomes. Eating less is not automatically safer than eating.

Protein goes up when dialysis starts

Before dialysis, protein is often restricted. Once dialysis starts it roughly doubles, to around 1.0 to 1.2 g per kg of ideal body weight per day, on both haemodialysis and peritoneal dialysis (KDOQI Nutrition, 2020), because dialysis itself removes protein and amino acids. People who carry the pre-dialysis rules into dialysis get malnourished. If nobody has explicitly told you the rule changed, ask.

Salt is the lever. Not the water glass.

The most useful fluid advice is not "drink less". It is "eat less salt and you will want to drink less". Salt drives thirst, thirst drives drinking, and everything you drink has to be pulled off in the next session. The faster it comes off, the more likely you are to crash, cramp and feel wrecked afterwards. As NIDDK puts it: "Too much sodium makes you thirsty, which makes you drink more liquid."

The target is under 2,300 mg of sodium a day (KDOQI Nutrition, 2020), roughly under 5 to 6 g of salt. Most of it is not in the salt cellar. It is in stock cubes, sauces, processed and cured meats, bread, takeaways and salted snacks.

One specific warning: salt substitutes are usually potassium chloride, and they are generally not suitable if you have kidney failure. Check the packet, and check any "low sodium" seasoning in a self-catering kitchen.

We are not going to give you a fluid number

Your allowance depends on your remaining urine output, your modality and your unit. Kidney Care UK is blunt: there is no one-size-fits-all advice on fluid in hot weather, and you should never change your fluid restriction, your diuretics or your blood pressure medicines on your own, even in extreme heat.

Heat cuts both ways. Sweating on top of fluid removal can tip you into dehydration, low blood pressure, cramps or fainting. Drinking to thirst in tropical heat can tip you into fluid overload: breathlessness, swollen ankles and face, headaches, no energy. Your allowance does not automatically go up because you are near a beach. It is individual, and it is a conversation with your unit.

Remember what counts as fluid: soup, gravy, sauces, ice, jelly, ice cream, yoghurt, and juicy fruit. In a resort, the iced drinks, the sorbet and the fruit platter are exactly the trap.

Coconut is the headline warning

Coconut water is sold everywhere in the tropics as a natural health drink. For someone on dialysis it is a double hit: it is a fluid, and it is a potassium load.

The numbers below are per 100 g, from the USDA FoodData Central database, retrieved on 13 July 2026.

Food	Potassium (mg per 100 g)
Breadfruit seeds, raw	941
Avocado, raw (California)	507
Breadfruit, raw	490
Banana, raw	358
Coconut meat, raw	356
Avocado, raw (Florida)	351
Cassava, raw	271
Coconut milk, raw	263
Coconut water, from the nut	250
Coconut water, ready to drink, unsweetened	165

Coconut milk in a curry is potassium you cannot see on the plate. That is worth knowing before you order it three nights in a row.

Breadfruit and cassava are the local staples nobody warned you about

Breadfruit at 490 mg per 100 g is in avocado territory, and avocado is on every renal "be careful" list in the world. Breadfruit seeds are higher still, and cassava is not far behind. These are traditional, everyday Seychellois carbohydrates, and they do not appear on a UK or US renal diet sheet at all. If your potassium runs high and nobody has ever asked you about breadfruit, that is a conversation worth starting.

Boiling starchy vegetables in plenty of water and throwing the water away leaches potassium out of them, and that applies directly to breadfruit and cassava. We are deliberately not publishing a percentage, because we could not verify one for these foods, and a made-up number is worse than no number. Ask your dietitian how much they expect it to help.

The good news: not all tropical fruit is a problem

This is the part patients almost never get told.

Food	Potassium (mg per 100 g)
Papaya, raw	182
Mango, raw	168
Pineapple, raw	109 to 137

All three are lower in potassium than banana. Pineapple is notably low. There is a real difference between a diet of prohibitions and a diet where you know which pleasures are cheap, and this is one of the cheap ones.

Fish: excellent, but not free

Fish is the Seychelles staple, and it is exactly the high-quality protein that NIDDK recommends for people on haemodialysis, because it produces less waste for the amount of protein it provides. But it is not potassium-free or phosphate-free.

Yellowfin tuna, per 100 g	Potassium	Phosphorus
Fresh, raw	441 mg	278 mg
Fresh, cooked	527 mg	333 mg

Eat the fish. Watch the portion. Both things are true.

While we are here: NIDDK notes that people on haemodialysis are usually limited to about half a cup of milk a day, because of the phosphorus.

Phosphate: read the label, not the lentils

The single most useful fact about phosphate is that not all phosphate is equal. Phosphate added to food as an additive is almost completely absorbed. Phosphate occurring naturally in plants such as beans, nuts and grains is bound up and poorly absorbed. Animal foods sit in between (National Kidney Foundation).

So cutting processed food with phosphate additives is far higher yield than cutting lentils. Read ingredient lists for anything containing "PHOS". Dark colas, processed cheese, enhanced meats and convenience foods are the usual suspects.

And the trap to name out loud: the highest-phosphate foods are often the highest-protein foods, and you need protein. That is exactly why phosphate is managed with binders taken with food rather than by eating less. Binders only work if they are in your stomach at the same time as the food, which means with every meal and every snack.

Potassium depends on how you dialyse

On haemodialysis, especially over the long two-day gap, potassium is the sharp end. NIDDK is direct: too much potassium can be dangerous to your heart. On peritoneal dialysis, potassium is removed continuously and many people run low, and some are told to eat more, not less. The advice is not interchangeable, and neither is the diet sheet.

What to actually do with this article

Take it to a renal dietitian. Not a general dietitian, and not a leaflet. Bring your real food diary and your recent blood results, because the diet follows the numbers and the numbers change.

These tables are food composition values. They are here so that you can have an informed conversation about the food that is actually on your table, not so that you can hand yourself either permission or a prohibition.

Sources

• KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update, American Journal of Kidney Diseases.
• NIDDK, Eating and Nutrition for Hemodialysis. niddk.nih.gov
• National Kidney Foundation, Phosphorus and Your Diet. kidney.org
• Kidney Care UK, Stay safe in the heat and in the sun. kidneycareuk.org
• USDA FoodData Central, Foundation and SR Legacy datasets, retrieved 13 July 2026. fdc.nal.usda.gov

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This article is general information, not medical advice. It does not diagnose, it gives no doses, and it must never be used to start, stop or change a treatment. Your dialysis prescription, your fluid allowance, your diet and your medicines depend on your own blood results, your own remaining kidney function and your own other conditions, and those decisions belong with you and your kidney care team. If you are unwell, contact your dialysis unit. In an emergency, call your local emergency number.