Let me give you a clear and practical answer.
Granulated sugar is almost pure sucrose, which is a simple carbohydrate. Carbohydrate provides 4 calories per gram. So the calorie value depends entirely on how many grams are in your spoon.

How much does 1 spoon weigh?
In nutrition, the standard measures are:
- 1 level teaspoon (tsp) of granulated sugar = about 4 grams.
- 1 level tablespoon (tbsp) = about 12 to 13 grams.
How many calories does that give?
Since 1 gram of carbohydrate gives 4 calories:
- 1 teaspoon (4 g) is about 16 calories
- 1 tablespoon (12 g) is about 48 calories

These values are consistent with USDA FoodData Central, which is the standard reference database for nutrient composition.
Does 1 spoon affect blood sugar?
Yes, it does raise blood glucose. Sucrose is rapidly digested and absorbed. If taken in tea on an empty stomach, the glucose rise can be noticeable. If taken along with a balanced meal containing fiber and protein, the rise may be slower, but it still counts toward your total carbohydrate intake.
Is one teaspoon daily harmful?
One teaspoon daily is not dangerous by itself. But in diabetes, the issue is total added sugar over time.
Even small daily additions can make it harder to:
- Maintain weight.
- Improve insulin sensitivity.
- Reach HbA1c targets.
Major guidelines advise limiting “free sugars” as part of long-term metabolic health.
Practical advice
- If your HbA1c is above target, reducing added sugar is a simple first step.
- Gradually reduce from 1 teaspoon to half teaspoon.
- Focus more on total daily carbohydrate quality rather than just one item.
So the direct answer is this:1 teaspoon of granulated sugar contains about 16 calories. 1 tablespoon contains about 48 calories.
The real impact depends on how often you take it and what the rest of your diet looks like.