Are Potatoes Good for Weight Loss? What the Research Says

Potatoes can help you feel full on fewer calories, which is a genuine advantage when you are trying to lose weight, but they do not burn fat and the research does not say they do. A post calling potatoes “king for fat loss” hit 1.6 million views on X on 7 November 2026. Here is what the studies behind that claim actually found.

Where did the “potatoes are king” claim come from?

Almost every version of this claim traces back to one paper: a 1995 study from the University of Sydney that gave 38 common foods a “satiety index” score. Boiled potatoes came top by a wide margin, and that single result has been doing the rounds in diet circles for thirty years. Along the way it has picked up claims the study never made, about fat burning, metabolism and potato-only diets.

What did the satiety index study actually find?

Susanna Holt and colleagues fed groups of 11 to 13 volunteers 1,000 kJ (240 kcal) portions of each food, then asked them to rate their hunger every 15 minutes for two hours. White bread was set at 100, and every other food was scored against it (European Journal of Clinical Nutrition, 1995).

Boiled potatoes scored 323, give or take 51, the highest of the 38 foods and about seven times the lowest, which was the croissant at 47 (abstract). Fish, porridge, oranges and apples also scored well. Cakes, doughnuts and chocolate bars scored low. The authors found no difference between boiled and mashed potato, and boiled potatoes were more filling than chips for the same calories.

Why potatoes? Mostly water and bulk. A 240 kcal serve of boiled potato weighs about 275 g, while 240 kcal of croissant is about 60 g. Protein and fibre help too, and potato is surprisingly decent on both for a starchy vegetable.

Keep the limits in mind. The groups were small, the test lasted two hours, and it measured how hungry people said they felt, not how much they ate over the following weeks or what happened to their weight. Nobody lost weight in that study, and nobody was meant to.

Does cooking method change the picture?

Completely. The same potato goes from one of the most filling foods per calorie to one of the least depending on what you do to it.

Potato, per 100 g	Energy (kcal)	Energy (kJ)
Boiled, flesh only	87	364
Sweet potato, boiled, without skin	76	318
French fries, fast food	about 310	about 1,300
Potato crisps (chips), plain, salted	532	2,226

Figures are from the USDA’s SR Legacy database (USDA FoodData Central). Frying roughly triples or quadruples the calories per gram, partly by driving off water and partly by adding oil, and the crisp is nearly all starch and fat with the water gone.

The long-term data lines up with that. A Harvard analysis that followed more than 120,000 adults for up to 20 years linked each extra daily serve of potato crisps to about 0.77 kg of weight gain per four years, the biggest effect of any food studied, with other potatoes at about 0.58 kg and french fries higher still (New England Journal of Medicine, 2011, NIH). That is observational, and the “other potatoes” category mixed boiled and mashed with fried, so it is not a verdict on a plain boiled spud. It is a fair warning that “potato” in the real world often means chips.

The trial evidence is kinder to the plain potato. In an eight-week feeding study at Pennington Biomedical Research Center, adults with insulin resistance ate a low-energy-density diet built around either potatoes or beans; both groups lost weight, about 5.6% on potatoes and 4.1% on beans, with no significant difference between them (Journal of Medicinal Food, 2022). The point of that study was energy density: lots of food volume for the calories. Potatoes delivered it, and so did beans. Neither was magic.

One more trial gets quoted a lot. In 2022, 180 adults ate 300 kcal of either french fries or almonds every day for 30 days, and neither group gained a meaningful amount of weight (American Journal of Clinical Nutrition). It was funded by the potato industry and compared fries to almonds rather than to nothing, which critics were quick to note (Food Politics). Read it as “a modest daily portion of chips did not wreck 30 days”, not as a green light.

What about cooled potatoes and resistant starch?

When you cook a potato and then chill it, some of its starch rearranges into a form your small intestine cannot digest, called resistant starch. It behaves more like fibre: fewer absorbed calories, food for gut bacteria, and a slower rise in blood sugar. Reheating reverses part of that, but not all of it, and longer, colder chilling produces more (Proceedings of the Nutrition Society).

The human evidence is small and mixed. In a University of Surrey crossover study of eight people, mashed potato that had been chilled and reheated produced an insulin peak about a fifth lower than freshly made mash, with no significant difference in blood glucose (Proceedings of the Nutrition Society). Diabetes UK gives the same practical advice: cooking and cooling starchy foods can lower their glycaemic impact a little (Diabetes UK). It is a real effect and a modest one. Potato salad is not a weight loss hack; it is a slightly better potato.

If you do cook ahead, cool the potatoes within two hours, keep them in the fridge, and use them within a few days. Cooked potato left warm is a food poisoning risk, which we cover in how long does potato soup last in the fridge?

Potato or sweet potato for weight loss?

Boiled, there is little in it. Sweet potato is slightly lower in calories per 100 g and much higher in vitamin A; white potato has a bit more potassium and protein. Both are mostly water and starch. The 1995 satiety study did not test sweet potato, so the “323” figure belongs to the white potato alone. Either one baked or roasted with a little oil is still a reasonable choice. Either one deep-fried is not, and sweet potato fries are not a free pass. For portion sizes and what a medium sweet potato actually weighs, see how much does a sweet potato weigh?

So can potatoes help with weight loss?

They can help you feel full on fewer calories, which is the part of weight loss most people find hardest. That is the honest summary of the research. The rest of the claim, that potatoes burn fat or drive weight loss on their own, is not supported by anything we found.

Weight changes with your whole diet over months, not with one food. A boiled potato with a bit of protein and vegetables beside it is a filling, cheap, low-fat meal. The same potato fried is one of the most energy-dense things in the supermarket. If you are trying to lose weight, especially if you have diabetes, kidney disease or another condition that affects what you should eat, a GP or an Accredited Practising Dietitian can tell you how potatoes fit into your plan. A viral post cannot.

Common questions

Are boiled potatoes good for weight loss?

They may help. Boiled potatoes scored highest of 38 foods on the 1995 satiety index, meaning people felt fuller for the same calories, and an eight-week trial found a potato-based low-energy-density diet produced weight loss similar to a bean-based one. They do not cause fat loss on their own.

How many calories are in a boiled potato?

About 87 kcal (364 kJ) per 100 g of boiled flesh, according to USDA data. A medium potato of around 170 g boiled is roughly 150 kcal before any butter.

Are sweet potatoes better than potatoes for weight loss?

Not meaningfully. Boiled sweet potato is about 76 kcal per 100 g against 87 for white potato, and it has far more vitamin A. How you cook either matters more than which you choose.

Do cold potatoes have fewer calories?

Slightly. Chilling cooked potatoes converts some starch into resistant starch, which your body does not digest. A small study found a lower insulin response to reheated mash. The effect is modest, not a shortcut.

Is a potato-only diet safe?

No one should try it without medical supervision. Potatoes lack several essential nutrients, including vitamin B12, adequate protein and most fats, and a single-food diet is not something any dietitian recommends.

Do potatoes make you gain weight?

Plain boiled or baked potatoes in normal portions did not cause weight gain in trials. Long-term observational data links potato crisps and french fries to weight gain more strongly than almost any other food.

The bottom line

Potatoes earn their reputation for being filling, and a boiled one is a good ally if you are trying to eat less. That is where the evidence stops. No food is king for fat loss, the same potato fried is one of the most calorie-dense foods there is, and your overall diet, with advice from a doctor or dietitian where it matters, is what decides your weight.

More on potatoes: Fresh Food · How much does a sweet potato weigh? · Black spots on sweet potato · Rotten potatoes: smell and taste · Storing potato chips