Sweet Potato — calories & nutrition
By Jenny Updated
Sweet potato has become one of the most popular healthy-eating staples in British kitchens over the past decade, and it's well-deserved. With around 86 calories per 100g raw, a medium glycaemic index, excellent fibre content, and a brilliant natural sweetness that works in everything from roasted wedges to curries, sweet potato is as versatile as it is nutritious.
Compared to a standard white potato at around 77 kcal per 100g, sweet potato is marginally higher in calories but packs considerably more beta-carotene — the antioxidant that gives it that vivid orange colour — plus more vitamin C and a slightly lower glycaemic impact when boiled or steamed. The fibre content also makes it more filling per portion than plain white potato, which means you often don't need as much to feel satisfied.
On Slimming World, sweet potato counts as a Free Food, so you can eat it without counting Syns. The most popular preparation is baked — scrub, pierce, and roast at 200°C for 45–60 minutes until the skin is crisp and the flesh is soft and caramelised. Make syn-free wedges by cutting into thick chips and roasting with spray oil, paprika, and garlic. It works beautifully in curries, soups, and fritters too.
Sweet Potato nutrition breakdown
| Portion | Calories | Carbs (g) | Fat (g) | Protein (g) |
|---|---|---|---|---|
| 100g raw | 86 | 20 | 0 | 2 |
| Medium sweet potato, ~150g raw | 129 | 30 | 0 | 2 |
| Large sweet potato, ~200g raw | 172 | 40 | 0 | 3 |
| 100g baked flesh only | 90 | 21 | 0 | 2 |
How Sweet Potato compares
Calories per 100g
FAQs
How many calories are in a sweet potato?
A medium sweet potato weighing around 150g raw contains approximately 129 calories. A large sweet potato at 200g is around 172 kcal. Per 100g raw, sweet potato provides about 86 calories. Baking concentrates the sugars slightly, bringing it to around 90 kcal per 100g of flesh once cooked. These values are for plain sweet potato — adding butter or oil will increase the calorie count significantly.
Is sweet potato a Free Food on Slimming World?
Yes — sweet potato is a Free Food on Slimming World. You can eat it without measuring or counting Syns as part of your Food Optimising day. This applies to sweet potato that is baked, boiled, steamed, or roasted with spray oil (Frylight). If you add butter, oil, or a creamy sauce, those additions will carry Syns. Sweet potato wedges made with Frylight are one of the most popular SW Free Food comfort dishes.
Is sweet potato healthier than white potato?
Sweet potato and white potato are both nutritious foods with similar calorie counts — sweet potato at around 86 kcal per 100g raw versus white potato at around 77 kcal. Sweet potato has the edge nutritionally due to its very high beta-carotene content, more vitamin C, and slightly better fibre profile. White potato is higher in potassium. For weight loss purposes both are excellent Free Foods on Slimming World, so the choice comes down to taste and what you're cooking.
How do you cook sweet potato without adding calories?
The best zero-added-calorie cooking methods for sweet potato are baking whole in its skin, steaming, or boiling. For wedges or chips, a few sprays of Frylight (approximately 1 calorie per spray) counts as essentially calorie-free. Season with smoked paprika, cumin, garlic granules, and salt, then roast at 200–220°C for 25–35 minutes, turning halfway through. The natural sugars caramelise beautifully without any added fat. Avoid frying in oil, which will add 100+ calories per tablespoon.
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