How many calories in a banana? By size, ripeness and form

A banana is the fruit you grab on your way out in the morning, throw into a gym bag or mash into porridge, without ever weighing it. Yet between a very small banana and a very large one, the gap is more than 60 kcal. According to Ciqual, the French national food composition table run by the food safety agency ANSES, 100 g of raw banana without the peel provides 87.6 kcal, 19.7 g of carbohydrate including 15.6 g of sugars, 2.7 g of fibre, just over 1 g of protein and almost no fat.

The real question is how much your banana weighs once peeled. The USDA, the US Department of Agriculture, which publishes the FoodData Central database, gives reference weights by length: 81 g of flesh for an extra small banana, 118 g for a medium one and 152 g for an extra large one. With those weights, a medium banana provides about 103 kcal. Using its own analyses (89 kcal per 100 g), the USDA gets 105 kcal for the same banana.

Norway’s Matvaretabellen tells the same story: 88 kcal per 100 g and 120 g for one banana, which makes 106 kcal. Per piece of fruit, the gaps between the big food tables add up to two or three calories, nothing that changes your day.

In a banana, almost all the calories come from carbohydrate. A ripe banana mostly contains sugars (glucose, fructose and sucrose) plus some leftover starch, around 4 g per 100 g according to the European tables. Water, which makes up three quarters of the weight, and fibre, about 2 to 3 g per 100 g, explain why a banana stays moderate in calories despite its reputation as a sugary fruit.

The table compares the three big food tables. One difference may surprise you: the USDA shows 22.8 g of carbohydrate, against 19.7 g for Ciqual and Matvaretabellen. It is not a different banana, it is a different method: in the United States, carbohydrate is calculated “by difference” and includes fibre, while European tables count fibre separately.

Weight for weight, a banana is denser than many fruits: 87.6 kcal per 100 g, against 54 kcal for a raw apple with its peel, again according to Ciqual. Our guide on apple calories goes through that comparison in detail.

Leave a green banana in the fruit bowl for a few days and it changes: sweeter, softer, then flecked with brown. It is not just your imagination. In an under-ripe banana, starch makes up 80 to 90% of the carbohydrate; as the fruit ripens, it turns into sugars. A study published in 1986 in the American Journal of Clinical Nutrition measured the scale of the change: starch fell from 37% of the dry weight in the least ripe bananas to 3% in the ripest.

This change does not create calories, but it changes what happens to them. In the same study, carried out in people with an ileostomy (which makes it possible to collect what leaves the small intestine), up to 90% of the banana starch was not digested, and the greener the banana, the more got through. This resistant starch travels on to the colon, like fibre: the amount escaping digestion could reach eight times the fibre content of the banana. Food tables still give a single value, for a banana that is ready to eat, and none of them reliably puts a number on the calorie gap by ripeness. For your tracker, stick with the same figure.

Ripeness does affect blood sugar, though. In a small Danish study of ten people with type 2 diabetes, the under-ripe banana had a glycaemic index of 31, against 53 for the over-ripe one. Other published measurements broadly point the same way, with wide gaps depending on the variety and the participants. To understand what this index measures and where it falls short, read our guide on the glycaemic index.

Take the water out of a banana and its calories become concentrated. The dried banana in the Ciqual table, almost fully dehydrated (3% water), provides 365 kcal per 100 g and 47 g of sugars. The soft dried bananas sold in bags keep more water, so they have slightly fewer calories per 100 g: check the label. For 30 g, the dried fruit portion used by the NHS, the UK health service, count about 110 kcal, roughly the same as a fresh banana.

Banana chips are another story. They are not simply dried bananas but fried slices, sometimes sweetened (5.5 g of added sugar per 100 g in the Norwegian analysis). The result: 499 kcal per 100 g according to Matvaretabellen, 519 kcal according to the USDA, with more than 30 g of fat, mostly saturated. A 30 g handful provides about 150 kcal. The NHS also advises eating dried fruit as part of a meal rather than as a between-meal snack, to limit the effect of sugar on your teeth.

Finally, plantain is cooked like a vegetable. Richer in starch than a dessert banana, it provides 132 kcal per 100 g raw and 125 kcal cooked according to Ciqual. Fried, it climbs to 236 kcal per 100 g when ripe and up to 309 kcal when green, according to USDA analyses.

A banana rarely stays on its own for long: it ends up spread with peanut butter, blended with milk or sliced into a bowl of oats. The banana is the same, it is the extras that change the total. A tablespoon of peanut butter doubles the calories of the snack, but it also adds 3.5 g of protein and some fat, which make it a more complete snack.

The table covers common combinations, made with a 118 g medium banana. For more ideas between meals, our guide to healthy snacks offers a selection.

The cyclist pulling a banana out of a jersey pocket is not a baseless cliché. A medium banana provides about 23 g of carbohydrate, with almost no fat, in natural packaging you can take anywhere. A study published in 2012 put it to the test: 14 trained cyclists rode two 75 km time trials, once with bananas and once with a 6% carbohydrate drink, taking 0.2 g of carbohydrate per kilo of body weight every 15 minutes. Performance did not differ (2 h 25 min against 2 h 22 min on average, a non-significant gap), and neither did blood sugar. The study was partly funded by Dole, a major banana producer, and carried out with two of its scientists: it shows that bananas did as well as a sports drink in these conditions, not that they did better.

How many do you need? For exercise lasting about an hour, small amounts of carbohydrate are enough, according to sports scientist Asker Jeukendrup. For 2 to 3 hours, he recommends up to about 60 g of carbohydrate an hour, roughly two and a half bananas. The 2012 study protocol was in the same range: 56 g an hour for a 70 kg cyclist. Before a workout, a banana is one of the easiest snacks to fit in; our guide on what to eat before exercise covers the right timing for each type of effort.

No single food makes you gain weight: what counts is your balance over the day. With just over 100 kcal, 3 g of fibre and almost no fat, a medium banana is a reasonable snack, and it counts as one of your five daily portions of fruit and vegetables: the NHS names the banana as its example of a portion for a medium-sized fruit.

Its reputation as an overly sugary fruit comes mostly from its density: weight for weight, it has more calories than an apple. But a whole banana (103 kcal) still has half the calories of a slice of banana bread (195 kcal). Calories mostly pile up with concentrated forms, such as chips and dried banana, and with whatever you add around it.

A 118 g medium banana without the peel has just over 100 kcal, 23 g of carbohydrate and 3 g of fibre; count about 70 kcal for an extra small one and 135 kcal for an extra large one. Weighed with the peel, it comes to only about 58 kcal per 100 g. Green or spotty, it keeps roughly the same calories: ripeness mostly changes the share of starch and sugars, and therefore the blood sugar response. Concentrated forms change everything: 365 kcal per 100 g of dried banana, around 500 kcal for chips. During exercise, bananas did as well as a sports drink in the available study, and when you want to lose weight, they remain an easy snack to count, as long as you keep an eye on what comes with them.