The role of dietary sugars, overweight, and obesity in type 2 diabetes mellitus: a narrative review

Nowadays, there is still a popular belief that dietary sugars, in particular sucrose, are directly linked to the development of type 2 diabetes mellitus (T2DM). Furthermore, since insulin action is impaired in T2DM, it is still believed that excluding dietary sugars from the diet can adequately treat T2DM. This might be based on the assumption that dietary sugars have a stronger impact on blood glucose levels than other carbohydrates. Therefore, the aim of this review is to discuss the effects of dietary sugars intake, including sugar-sweetened beverages (SSBs) against the background of overall energy intake and weight gain in the development of T2DM. Furthermore, the effect of dietary sugars, including SSBs on glycemic control will be discussed. Results from various systematic reviews and meta-analyses do not support the idea that the intake of sucrose and other dietary sugars is linked to T2DM. Long-chain or complex carbohydrates can have a greater impact on postprandial glycemic response than sucrose. SSBs do not affect glycemic control if substituted for other calorie sources. Current scientific evidence clearly points toward excess energy intake followed by excess body fat gain being most relevant in the development of T2DM.