A medium baked potato (200g) contains 173 kcal and is free on Slimming World. Boiled potatoes are 77 kcal per 100g and also free. Chips are where the calories multiply — oven chips are around 150 kcal per 100g, chippy chips around 250 kcal per 100g, and McDonald's fries around 312 kcal per 100g.
The potato itself is not the issue. It is one of the most filling foods per calorie available. The problem is how most people eat potatoes — roasted in oil, fried, or loaded with butter and cheese. Plain potatoes in almost any format are low calorie. The additions are not.
This guide covers calories for every potato format — baked, boiled, mashed, roasted, chips, and crisps — with Slimming World syn values and WW SmartPoints.
A raw potato contains approximately 77 kcal per 100g. A medium baked potato (200g) is 173 kcal. A large baked potato (300g) is 260 kcal. Boiled potatoes are similar at 77 kcal per 100g cooked. All plain potatoes are free on Slimming World.
| Potato type | Portion | Calories | SW Syns | WW Points |
|---|---|---|---|---|
| Baked potato (medium) | 200g | 173 kcal | Free | 5 |
| Baked potato (large) | 300g | 260 kcal | Free | 7 |
| Boiled potatoes | 180g | 140 kcal | Free | 4 |
| Mashed potato (no butter/milk) | 180g | 144 kcal | Free | 4 |
| Roasted potatoes (Fry Light) | 180g | 160 kcal | Free | 4 |
| Roasted potatoes (oil) | 180g | 270 kcal | 6 | 7 |
| Oven chips (supermarket) | 165g | 248 kcal | 6 | 7 |
| Chippy chips | 200g | 500 kcal | 12 | 14 |
| McDonald's Medium Fries | 117g | 366 kcal | 9 | 10 |
| Sweet potato (baked) | 200g | 172 kcal | Free | 5 |
| Sweet potato fries (oven, no oil) | 150g | 135 kcal | Free | 4 |
The difference between roasted potatoes with oil (270 kcal, 6 syns) and roasted potatoes with Fry Light (160 kcal, free) is 110 kcal and 6 syns for exactly the same meal. Fry Light is the most useful swap for any potato dish that usually requires oil.
Yes — all plain potatoes are free on Slimming World. Baked, boiled, steamed, and mashed potato (without butter, milk, or cream) are all free. Potatoes cooked in oil — roasted with oil, fried, chippy chips, oven chips — carry a syn cost because of the added fat.
Sweet potatoes are also free on Slimming World. The same rules apply: plain and cooked without fat is free; cooked with oil or butter carries a syn cost. Most sweet potato fries recipes use Fry Light, which keeps them free. Shop-bought frozen sweet potato fries often contain oil in the coating — check the ingredients before assuming they are free.
A medium baked potato (200g without skin) contains 173 kcal and is free on Slimming World. A large baked potato (300g) is 260 kcal. The skin adds minimal calories — eating a baked potato with skin adds around 10–15 kcal.
Baked potatoes become high calorie through the toppings. A plain baked potato is 173 kcal. Add a tablespoon of butter (100 kcal, 4 syns), 30g of cheddar (125 kcal, 6 syns), and a tablespoon of sour cream (50 kcal, 2.5 syns) and the same potato is now 448 kcal and 12.5 syns before any filling. The SW approach is to use quark, cottage cheese, or baked beans (all free) as the topping instead.
Chippy chips contain approximately 240–280 kcal per 100g — around 500 kcal for a standard portion. Oven chips from a supermarket are 140–160 kcal per 100g, making them significantly lower calorie than deep-fried chips. Homemade oven chips using Fry Light are around 100 kcal per 100g and free on Slimming World.
The calorie difference between homemade Fry Light chips and chippy chips is approximately 400 kcal per portion. That is a significant saving for a meal that tastes broadly similar — oven chips made from par-boiled sliced potatoes sprayed with Fry Light and seasoned are one of the most popular free SW side dishes for exactly this reason.
Plain mashed potato — potato, water, and seasoning only — contains approximately 80 kcal per 100g. A standard 180g portion is 144 kcal and free on Slimming World. Mashed potato made with butter (typically 25g per serving, 180 kcal extra) and whole milk (50ml, 30 kcal extra) comes to approximately 350 kcal per 180g portion and around 8–9 syns.
SW mashed potato uses skimmed milk and a small amount of quark or fat-free fromage frais instead of butter — this gives a creamy texture for free. The result is noticeably less rich than butter mash but still satisfying as a side dish. Most members adjust to it within a week and stop noticing the difference.
Sweet potato contains approximately 86 kcal per 100g raw — slightly more than white potato at 77 kcal per 100g. The calorie difference is small. Sweet potato has a higher glycaemic index than white potato but a lower glycaemic load per typical serving, meaning blood sugar rises at a similar rate.
Both are free on Slimming World. Choose based on taste preference — the calorie difference is not significant enough to make one a better weight loss choice than the other when cooking methods are the same.
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