How many calories are in a teaspoon of sugar?
A level teaspoon of granulated sugar (about 4 g) is roughly 16 kcal. A heaped teaspoon is 6–7 g, so about 25 kcal. Sugar is pure carbohydrate at 4 kcal per gram, which makes the arithmetic genuinely simple — and easy to under-count, because it arrives sixteen calories at a time.
Per portion
| Portion | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| 1 level teaspoon, sachet or cube (4 g) | ~16 kcal | 0 g | 4 g | 0 g |
| 1 heaped teaspoon (6–7 g) | ~25 kcal | 0 g | 6–7 g | 0 g |
| 1 tablespoon (13 g) | ~50 kcal | 0 g | 13 g | 0 g |
| 330 ml can of cola (~35 g sugar) | ~140 kcal | 0 g | 35 g | 0 g |
| 500 ml bottle of cola (~53 g sugar) | ~210 kcal | 0 g | 53 g | 0 g |
| 100 g (about 8 tablespoons) | ~390 kcal | 0 g | 100 g | 0 g |
What changes the number
Heaped or level. The biggest variable at the table. A heaped teaspoon holds 50–70% more than a level one, so “two sugars” is anywhere from 32 to 50 kcal.
Which sugar. Caster, granulated, demerara and brown sugar all land between 380 and 400 kcal per 100 g. Brown sugar is marginally lower per 100 g because it holds some moisture, but it packs more densely into a spoon, so per teaspoon it comes out the same. No saving.
Honey and syrups. Honey is about 300 kcal per 100 g and maple syrup about 260, both lower than sugar because they contain water. But they are denser, so a teaspoon of honey weighs about 7 g and comes to roughly 21 kcal — slightly more than a teaspoon of sugar. Jaggery is within a couple of per cent of white sugar per gram.
Whether it is dissolved. Sugar in a drink contributes no chewing, no bulk and almost no appetite suppression. The same 50 kcal in a biscuit at least registers as food.
Where it fits in a deficit
Do the day’s arithmetic once and the scale becomes obvious. Four teas with two teaspoons each is about 130 kcal. A 500 ml soft drink is about 210. Two biscuits are about 140. A flavoured yoghurt pot carries 15 g of sugar before the rest of the pot. That is roughly 500 kcal, none of it a meal, and more than most people’s whole calorie deficit.
Sugar is not poison, and there is no metabolic penalty making 100 kcal of it behave like 150. The awkwardness is structural: it carries no protein, fibre or water, so it does nothing for fullness per calorie — the bottom of the density ladder — and it arrives in a dozen untracked moments a day rather than three visible ones.
For scale, the WHO suggests keeping free sugars under 10% of energy, ideally under 5%. On 2,000 kcal that is 50 g (twelve level teaspoons) and 25 g (six). The lower figure is one bottle of soft drink.
The highest-yield change is usually drinks rather than food. Going from two teaspoons to one across four daily teas saves about 65 kcal a day, roughly 450 a week, with nothing on your plate changing. Taste adapts within a fortnight.
Sugar you did not add
Most of the sugar in a typical day was not spooned in by the person eating it. A tablespoon of ketchup holds about a teaspoon of sugar, as does a serving of many pasta sauces, most breakfast cereals, and sweetened peanut butter at 2–3 g per tablespoon.
The most useful habit is a conversion: 4 g of sugar on a label is one teaspoon. Read “27 g of sugars” as “nearly seven teaspoons” and it stops being abstract. Two cautions when reading the label: the “of which sugars” line includes naturally occurring sugars, so plain milk and whole fruit look worse than they are; and “no added sugar” can still mean plenty of it arriving via fruit juice or concentrate.
Figures are typical values and vary by variety, size and preparation. General information, not medical advice.