Ever grabbed a banana thinking it’s a super low-cal snack, only to find out the size you picked was double the calories of a smaller one? Bananas are brilliant for us, and totally Free on Slimming World, but their calorie count varies wildly by size – from 71 to 160 kcal! Let’s get into the nitty-gritty.
A medium banana (120g) contains 107 kcal. Bananas are Free Food on Slimming World — unlimited, no syns, at any ripe stage. On WW, a medium banana costs 0 SmartPoints under the current plan.
Banana calories vary more than most people expect because size varies so much. A small banana from a bunch can be 80g and 71 kcal. A large banana from a supermarket bowl can be 160g and 142 kcal. The same food, eaten in the same way, can be twice the calories depending on which banana you pick up. It's properly surprising when you think about it!
This guide covers exact calorie counts for every banana size, dried banana and banana chips, banana in recipes, and how bananas fit into Slimming World and WW in 2026.
A medium banana (120g peeled weight) contains 107 kcal. Per 100g, bananas contain 89 kcal. The range across sizes runs from 71 kcal for a small banana to 160 kcal for an extra-large banana. It really goes to show how much difference a slightly bigger banana can make to your daily count!
| Banana size | Peeled weight | Calories | Carbs | SW |
|---|---|---|---|---|
| Small | 80g | 71 kcal | 18g | Free |
| Medium | 120g | 107 kcal | 27g | Free |
| Large | 150g | 134 kcal | 34g | Free |
| Extra large | 180g | 160 kcal | 41g | Free |
| Baby/finger banana | 50g | 45 kcal | 11g | Free |
The peeled weight is what matters — always weigh or estimate after removing the skin. A typical supermarket banana loses around 30–35% of its weight in the skin, so don't get caught out weighing it with the peel still on!
Yes, absolutely! Bananas are Free Food on Slimming World — no syn cost at any portion size. All fresh fruit is Free on the plan, and bananas are no exception despite being higher in sugar and calories than most other fruits. I know, right? You'd think with all that sweetness they'd have a syn value, but nope!
Slimming World's Free Food list is based on the principle that the fibre and water content of whole fruit regulates intake naturally. A banana at 107 kcal is more filling than 107 kcal of biscuits because of the 2.6g fibre and bulk. Members who eat bananas as snacks typically find the satiety lasts 2–3 hours, which is brilliant for keeping those mid-morning or afternoon munchies at bay.
Dried banana and banana chips are not Free — the dehydration removes the water content that creates satiety, concentrating the sugar without the bulk. These are definitely a syn trap, so do check the dried banana section below for their syn values.
They certainly can be! Dried banana slices contain approximately 290 kcal per 100g. Banana chips (fried in oil) contain 519 kcal per 100g — nearly six times the calorie density of fresh banana. A standard 30g bag of banana chips contains around 156 kcal and costs approximately 8 syns on Slimming World. That's quite a lot for a small bag, so be mindful!
| Product | Portion | Calories | SW Syns |
|---|---|---|---|
| Fresh banana (medium) | 120g | 107 kcal | Free |
| Dried banana slices | 30g | 87 kcal | 4.5 |
| Banana chips (fried) | 30g | 156 kcal | 8 |
| Freeze-dried banana | 20g | 70 kcal | 3.5 |
Banana chips are not a low-calorie snack. The oil used in frying doubles the calorie count compared to plain dried banana slices. Honestly, if you're watching your calories, stick to a fresh banana every time over those crispy little devils!
A banana smoothie made with one medium banana (120g), 150ml skimmed milk, and no added sugar contains approximately 175 kcal. Adding yoghurt, honey, or peanut butter increases this significantly — a banana, peanut butter, and milk smoothie can reach 400–500 kcal per glass. That's basically a meal in itself, so be careful what you're chucking in!
On Slimming World, a banana smoothie blended from Free ingredients (banana, fat-free yoghurt, skimmed milk within HEA) costs 0 syns. However, blended fruit carries a syn cost in some interpretations of the plan because blending removes the need to chew and reduces satiety. Personally, I find I'm much hungrier quicker after a smoothie than eating the whole fruit, so it makes sense. Always check the official app for current guidance on smoothies, as it can sometimes change!
Absolutely! Bananas support weight loss when eaten as a replacement for higher-calorie snacks. A medium banana at 107 kcal delivers 2.6g fibre and 27g slow-release carbohydrate — a more satiating option than crisps, biscuits, or chocolate at the same or higher calorie count. I always grab one when I'm feeling peckish between meals, and it properly keeps me going.
The common concern that bananas are "too high in sugar" for weight loss is not supported by evidence. A medium banana contains 14g sugar — less than a small glass of orange juice, and delivered alongside fibre that slows absorption. The NHS includes bananas in its five-a-day guidance without qualification, so you know they're good for you.
The practical rule: a banana as a snack is a good choice. Banana-flavoured products — banana bread, banana chips, banana milkshake — are not the same food and should not be treated as equivalent. Don't be fooled by the 'banana' label!
Oh, banana bread, the ultimate comfort bake! A slice of homemade banana bread (approximately 80g) contains 250–310 kcal depending on the recipe. Most banana bread recipes use 2–3 ripe bananas plus butter, sugar, and flour — making a single slice nutritionally closer to cake than fruit. Delicious, but definitely a treat!
Slimming World banana bread recipes using fat-free yoghurt, sweetener, and self-raising flour (as HEB) can reduce this to 120–150 kcal per slice and 1–3 syns. The key variable is whether the recipe uses butter and sugar — standard recipes do, SW-adapted recipes replace both. If you're on plan, definitely seek out a proper SW recipe!
Bananas contain 89 kcal per 100g peeled. This figure applies to fresh ripe bananas across all varieties available in UK supermarkets — Cavendish (the standard yellow banana), organic, and Fairtrade varieties are all within 2–3 kcal per 100g of each other. So no need to faff about picking a specific type!
Unripe (green) bananas contain slightly fewer digestible calories because some of the starch has not yet converted to sugar — around 80–85 kcal per 100g. Overripe (black-skinned) bananas are slightly higher at around 95 kcal per 100g because all starch has converted to sugar. For practical purposes, though, just treat all ripe bananas as 89 kcal per 100g. It keeps things simple!
Brilliant news for my WW mates! A medium banana (120g) costs 0 SmartPoints on the current WW plan. WW moved bananas to 0 points as part of its ZeroPoint Foods update — the same change that made most fresh fruit 0 points. A large banana (150g) remains 0 points. Banana chips, dried banana, and banana-based products still carry a points value, so be careful with those. Always check the app if you're unsure!
Strawberries are an even lower-calorie fruit option at just 32 kcal per 100g. See Calories in Strawberries UK for a full portion breakdown.
For another popular fruit, see Calories in Grapes UK — including how green, red, and black grapes compare and why raisins cost syns.
Watermelon is even lower in calories than banana at just 30 kcal per 100g. See Calories in Watermelon UK for the full breakdown.
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