Calorie counting just became more complicated. A new study has found that baking can dramatically alter the sugar content and calorie count of some foods.

Published in the Journal of Nutrition and Food Sciences, the UBC study found that baked goods can lose up to 25 per cent of their sugar content during the baking process. This means that the sugar content and calories indicated on nutritional labels could be quite different from the end result.

“Our initial intention was to educate and remind the general public that the amount of added sugar stated in the nutrition facts table may not accurately reflect the actual calories from sugar that we consume,” said PhD student Ningjian Liang, the lead author of the study.

Sugar is lost due to browning processes and caramelization. The sugar in baked goods reacts with other ingredients and heat to convert into compounds that are hard to digest. These compounds are often excreted and do not contribute to the total calorie count of the food.

The study compared cakes baked with two kinds of sugar. Cakes baked with invert sugar, a mixture of glucose and fructose, lost on average of 20per cent of their sugar content during baking. Cakes baked with more conventional table sugar, sucrose, only lost about 6per cent.

Liang says this study could indicate that other nutrients are affected by the baking process. However, it is unlikely that this study will impact how companies report nutritional value. In order to calculate actual sugar content, manufacturers would need to extract and test each ingredient separately after baking.

“The whole extracting and separating process increases costs,” Liang says.