How many calories are in a teaspoon of sugar?

One level teaspoon of sugar (approximately 4g) contains 16 kcal, all from carbohydrate. This sounds small, but it adds up quickly — three sugars in tea three times a day is 144 kcal and 36g of pure sugar, equivalent to nearly 9 teaspoons. Per 100g, sugar delivers 400 kcal with zero protein, zero fat, zero fibre, and zero micronutrients.

Is brown sugar healthier than white sugar?

Nutritionally, brown sugar (demerara, muscovado, light brown, dark brown) is almost identical to white sugar. Brown varieties retain small amounts of molasses, which provides trace minerals like calcium, potassium, and iron — but in negligible quantities. Per 100g, demerara has 100g carbs and 401 kcal versus granulated at 99.7g carbs and 400 kcal. The glycaemic response is effectively the same. Choosing brown over white sugar for health reasons makes no meaningful difference.

What is the glycaemic index of sugar?

Table sugar (sucrose) has a glycaemic index of approximately 65, which is classified as medium-high. Pure glucose scores 100 on the GI scale, and sucrose scores lower because it is 50% fructose (which is processed by the liver rather than entering the bloodstream directly as glucose). However, a GI of 65 still causes a significant blood sugar spike, especially when consumed in liquid form or on an empty stomach.

Glucose: Very LowNOVA 2

Nutritional Information for Sugar

Sugar is a processed culinary ingredient that is essentially pure carbohydrate — 100g of sugar contains approximately 100g of carbs and 400 kcal, with virtually no other nutrients. From a SpikeSaver perspective, sugar is the benchmark for glucose impact: a very high GI of around 65 means it hits your bloodstream fast. All common types — granulated, caster, demerara, muscovado, icing — are nutritionally near-identical. The differences are texture, colour, and trace minerals in brown varieties, but the glucose response is functionally the same across all of them.

Nutrition per 100g

Nutrient	Per 100g	Per serving
Energy	400 kcal / 1700 kJ	16 kcal
Protein	0g	0g
Carbohydrates	99.7g	4g
of which sugars	99.7g	—
Fat	0g	0g
of which saturated	0g	—
Fibre	0g	—
Salt	0.13g	—

Serving size: 1 teaspoon (~4g) · Source: Tesco product page, October 2025

Glucose impact

Glycemic Index

Very Low

Glucose risk

Sugar is virtually 100% carbohydrate with a high glycaemic index (~65 for sucrose). A single teaspoon (4g) is minor, but sugar is rarely consumed in isolation — it accumulates across tea, coffee, baking, sauces, and processed foods. Because sucrose is 50% glucose and 50% fructose, it delivers a rapid blood sugar spike followed by a fructose load processed by the liver. Context matters: sugar in a cake with fat and protein will spike less than sugar dissolved in water.

Processing level

NOVA 2 (processed culinary ingredient)

Sugar is a processed culinary ingredient — it is extracted and purified from sugar cane or sugar beet through industrial processes (crushing, refining, crystallising). It is not consumed on its own as a meal but used as an ingredient in cooking and food manufacturing. White granulated and caster sugar are the most refined; demerara and muscovado retain small amounts of molasses but undergo similar processing. Icing sugar with anti-caking agents (tricalcium phosphate) remains NOVA 2.

Sugar at Tesco

Source: Tesco product page, October 2025

Tesco Golden Granulated Sugar 1Kg

£2.50*NOVA 2 (processed culinary ingredient)

Tesco Demerara Sugar 1Kg

£2.50*NOVA 2 (processed culinary ingredient)

Silver Spoon Granulated Sugar 2Kg

£2.15*NOVA 2 (processed culinary ingredient)

Silver Spoon Caster Sugar 1Kg

£2.25*NOVA 2 (processed culinary ingredient)

Silver Spoon Icing Sugar 1Kg

1 UPF marker

£2.55*NOVA 2 (processed culinary ingredient)

*Prices were correct at the time of collection and may have since changed. Check Tesco.com for current pricing.

What to watch for when shopping

All sugar types — granulated, caster, demerara, muscovado, icing — deliver essentially the same glucose hit per gram. Demerara and muscovado contain trace minerals from molasses but not enough to meaningfully change the nutritional profile. Icing sugar often contains an anti-caking agent (tricalcium phosphate) but remains NOVA 2. The real SpikeSaver concern is hidden sugar in processed foods: a single can of cola contains ~35g of sugar (nearly 9 teaspoons). Budget tip: Silver Spoon Granulated Sugar 2Kg at £2.15 (£1.08/kg) is the cheapest per-kilo option.

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