Potatoes: the carbohydrate nobody plans around

Potatoes get treated as filler. For a fighter running a deficit for 8 weeks they are closer to a solution, and there is a number behind that rather than an opinion.

The number

A study in the European Journal of Clinical Nutrition fed 38 foods to subjects in isocaloric portions, then measured how full people felt every 15 minutes over the following 2 hours.

White bread was set at 100 percent and everything else scored against it.

Highest of all 38, and not narrowly. It beat porridge by more than 100 points and brown rice by nearly 200.

The study also identified what predicted satiety across the whole set, and those answers explain why potatoes won.

Why that matters more than the macros

In a deficit that runs for weeks, hunger breaks plans far more often than macronutrient ratios do.

A fighter who is eating correctly and abandons it in week six has not failed on nutrition science. He has failed on being hungry every evening for a month and a half, which is a different problem with a different solution.

Two hundred and forty calories of boiled potato physically weighs more than 240 calories of almost anything else you could put on a plate. That heft, plus the water it carries, is doing the work.

Which is also why butter undoes it. Fat was the one predictor pointing the wrong way, and adding it removes the advantage you chose the food for.

Sweet potatoes, and the myth that will not die

Sweet potatoes carry a reputation as the athlete's version. The evidence for it is thin.

Per 100 grams the two are close to identical in carbohydrate, protein and fat. Sweet potato carries around a gram more fibre.

Potassium and vitamin B6 are roughly comparable, with white often slightly ahead on potassium.

One genuine difference exists, and it matters: orange sweet potato is extremely high in beta-carotene, the precursor to vitamin A, which white potato does not provide in meaningful amounts.

Note that white and purple sweet potato varieties do not carry it either.

The colour is the thing rather than the name.

On satiety, only white potato has the validated data. Sweet potato shares most of the relevant properties, similar water and similar weight per calorie, so it is probably close.

Nobody has put it through the same test.

The finding that settles the argument

How you cook it moves the glycaemic response far more than which one you choose.

A swing of roughly 50 points from cooking method alone, against a difference of 10 to 15 between the two vegetables.

The mechanism is starch gelatinisation. Raw potato starch sits in compact crystalline granules that enzymes struggle to break into. Heat and water make those granules swell and lose their structure, and the more completely that happens, the faster the starch is digested.

Dry heat does it more thoroughly than boiling.

So a boiled sweet potato beats a baked white potato by a wide margin. A baked sweet potato and a baked white potato are both high.

Anybody choosing sweet potato and then roasting it in oil has optimised the variable that barely matters and ignored the one that decides.

The skin is the whole fight week question

Most of a potato's fibre sits in and just under the skin. Remove it and what remains behaves much like white rice in the gut: bland, well tolerated, and low in residue.

Which puts potatoes in an unusual position on this site. Most foods are either in or out during the final days. This one changes category depending on how it is prepared.

Peeling costs you the fibre and keeps the rest. The weight and water per calorie are still there, so a peeled boiled potato remains one of the more filling things available in a week when almost everything else has been removed.

On fight day the timing rule applies as everywhere else: high-intensity work slows gastric emptying, and anything solid arriving close to the bell tends to stay put.

One practical note for the working fighter

Cold boiled potatoes are perfectly edible, even if nobody enjoys describing them that way.

For somebody fitting camp around a job, a container of boiled potatoes with a protein source is one of the few genuinely portable meals that needs no microwave, and that constraint decides more diets than any macronutrient argument does.

There is a small bonus. Cooling cooked potato converts some of the starch to resistant starch, which lowers the glycaemic response further. Reheating reduces the effect without eliminating it.

A minor gain rather than a strategy, and a reason not to treat the cold container as a compromise.

How much, in grams

Those portions look large and they are, which is the entire point. Four hundred grams of boiled potato is a substantial plate of food for the calories in a bowl of cereal.

Against rice: 300 grams of boiled potato and 165 grams of cooked white rice carry similar carbohydrate.

The potato weighs almost twice as much and, by the satiety data above, will do considerably more about hunger.

Potatoes lose relatively little weight when boiled, so raw and cooked weights are close enough that either works for tracking, unlike rice or oats.

Varieties, and which behave differently

Waxy potatoes hold their shape when boiled and have a firmer texture. Floury ones break down and are what you want for mashing.

For a fighter the practical difference is small, with one exception. Waxy varieties hold together better when boiled in advance and eaten cold, which makes them the better choice for the container that goes to work.

New potatoes are simply young ones, harvested early, with thinner skin and slightly firmer flesh. Nothing about them changes the reasoning on this page.

The one preparation that undoes all of it

Chips and roast potatoes belong in a different category, and the size of the gap needs stating.

A hundred grams of boiled potato is around 80 calories. The same weight roasted in oil is roughly double that, and deep-fried can be triple or more.

The satiety advantage described above disappears alongside it, because fat was the one predictor working in the wrong direction.

So the food that scored highest of 38 for fullness becomes an ordinary calorie-dense side dish, and it happens in the pan rather than in the vegetable.

Storage, and the one thing to avoid

Raw potatoes keep for weeks in a cool, dark, dry place, which makes them one of the cheapest carbohydrates to buy in quantity.

Not in the refrigerator, though. Cold storage converts some of the starch to sugar, which changes the taste and, when the potato is later cooked at high heat, increases the formation of acrylamide.

Keep them in a cupboard.

Green patches and sprouts indicate solanine, which is mildly toxic and concentrated in and just under the skin. Cut them away generously, and discard any potato that is extensively green or soft.

Boiled potatoes keep 3 to 4 days refrigerated, the same window as the rest of the batch-cooked food on this site.

What goes with it

Potatoes are a carbohydrate and nothing else in any useful quantity. Two grams of protein per 100, essentially no fat.

Which means the plate is only half built. A meal of potatoes alone is a large volume of food that leaves you short on protein for that feed, and the satiety advantage described above can hide that: you feel full and you have eaten 12 grams of protein.

The pairings that work in camp are the obvious ones, and the arithmetic is worth seeing once. Three hundred grams of boiled potato with 150 grams of chicken breast gives roughly 50 grams of carbohydrate and 46 of protein for around 400 calories.

That is a complete feed at a cost most fighters would accept in any week of camp.

Swap the chicken for white fish and the calories drop by 50 without much protein moving.

Potassium, and one honest correction

Potatoes carry more potassium than a banana per 100 grams, which is a fact that gets repeated because it surprises people.

It is true and it matters less than it sounds, for the reason set out under bananas: the evidence that dietary potassium prevents exercise cramp in a well-fed athlete is thin, and potassium is one of the electrolytes where no difference was found between athletes who cramp and athletes who do not.

So eat potatoes for the carbohydrate, the satiety and the practicality. The potassium is a bonus rather than a reason, and anybody selling it as a cramp solution is repeating the same error that attached itself to bananas 40 years ago.

Boil it and keep the butter off

• Boiled potato is the most filling thing measured, and hunger is what ends camps. Use that.
• Boil rather than bake or roast. It matters more than which potato you bought.
• Sweet or white is a preference, not a strategy. Take sweet if you want the vitamin A and you like it. Do not believe anybody who tells you it is a meaningful decision.
• Skin on in camp, peeled in the final days.
• Keep the butter off, especially in a deficit. Fat was the one thing in that study working against you.