How many calories are in a tomato?
A medium tomato — about 120 g — is roughly 22 kcal. Raw tomato runs about 18 kcal per 100 g and is around 95 per cent water, which makes the fresh fruit one of the least consequential things on a plate. Everything that matters happens once the water leaves.
Per portion
| Portion | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| 1 medium tomato (120 g) | ~22 kcal | 0.9 g | 4 g | 0.2 g |
| 100 g raw | ~18 kcal | 0.9 g | 3.9 g | 0.2 g |
| 10 cherry tomatoes (170 g) | ~30 kcal | 1.5 g | 7 g | 0.3 g |
| 400 g tin, chopped | ~75 kcal | 4 g | 15 g | 0.8 g |
| 100 g passata | ~30 kcal | 1.3 g | 6 g | 0.2 g |
| 100 g purée, double concentrate | ~80 kcal | 4 g | 16 g | 0.5 g |
| 100 g sun-dried, dry | ~260 kcal | 14 g | 56 g | 3 g |
| 100 g sun-dried in oil, drained | ~215 kcal | 5 g | 23 g | 14 g |
| 1 tbsp ketchup (17 g) | ~18 kcal | 0.2 g | 4.5 g | 0 g |
What changes the number
Concentration, almost entirely. Nothing in that table is a different plant. Take water out of tomato and the energy per gram climbs: 18 kcal fresh, about 30 as passata, 80 as double-concentrate purée, 260 dried. It takes several kilograms of tomatoes to make a kilogram of purée, and the sugars that were spread thinly through all that water end up in one spoonful.
Per portion the ladder flattens again, which is the part worth holding on to. A tablespoon of purée is 15 g — about 12 kcal. Two sun-dried halves are maybe 10 g, so 25 kcal dry or 45 kcal if they came out of oil. Dense per gram does not mean expensive per meal, as long as the portion stays spoon-sized.
Oil, in the pan and in the jar. A fresh-tomato sauce started in two tablespoons of oil carries about 240 kcal of oil and 70 kcal of tomato. Sun-dried tomatoes packed in oil are the same trick in reverse: the oil runs over 800 kcal per 100 g, so how much clings to them matters more than the fruit underneath. Grilled or fried tomatoes in a breakfast absorb whatever is in the pan.
Ketchup is mostly sugar. Around 22 g of sugar per 100 g — roughly a quarter of its weight — which accounts for most of its 100 kcal per 100 g. A tablespoon is only 18 kcal, so this is a condiment problem rather than a meal problem, until the bottle is tipped over a plate of chips.
Where it fits in a deficit
Fresh tomato is nearly free: a 300 g salad’s worth is about 55 kcal, with the bulk and water that make a calorie deficit tolerable. Fibre is modest at 1.2 g per 100 g, so it fills less durably than carrot does, and protein is negligible.
Its real value in a deficit is cooked. A 150 g passata base is about 45 kcal and carries flavour, acidity and salt into a dish for almost nothing — the cheapest alternative to a cream or fried-onion base there is. Tinned tomatoes are the single most useful thing in a deficit store cupboard.
Reading the label on a jar
Tomato products are where per-100 g labelling is most misleading, because nobody eats 100 g of them and almost everybody eats a whole jar between two.
- A 500 g jar of pasta sauce at 60 kcal per 100 g is 300 kcal. The label will quote a 125 g serving, which is a quarter of the jar.
- Many jarred sauces add oil and sugar: 5–10 g of sugar per 100 g is common, so check whether the carbohydrate figure is roughly double plain passata’s.
- Tins state drained weight as well as net weight. Chopped tomatoes in juice are all food; the difference matters for whole plum tomatoes.
The habit that helps is reading the figure for the whole pack, not the serving and dividing it by however many people are actually eating.
Figures are typical values and vary by variety, size and preparation. General information, not medical advice.