In terms of how our body uses sugar once it is absorbed, there is no difference between sugar that has been added to foods, and sugar which is naturally present. However the sugars found in fruits are contained within the cells of the fruit and are often consumed with other nutrients such as fibre. This means they are absorbed more slowly into our bloodstream meaning a smaller effect on blood sugar levels – unlike simple added sugars.
Sugars that have been added to foods such as cakes, sweets, sugary drinks and biscuits can cause a sharp rise in our blood sugar levels which is then met with a surge of insulin to help take the glucose up into our cells. This may then result in a corresponding drop in blood sugar soon after, which can lead to cravings and feelings of hunger. Choosing more complex carbohydrates can help to stabilise blood sugar and insulin levels.
Foods high in added sugars also tend to be low in other important nutrients, so eating these foods regularly means we are using our calories on less nutritious foods. This is one of the main reasons why we should aim to limit our sugar intake, as in doing so, we would have a much more nutritionally balanced and energy controlled diet, with less chance of weight gain and nutritional deficiencies.