Genetic factors can influence our ability to digest carbohydrates. The gene encoding for salivary α-amylase, AMY1, has gathered attention in recent years due to the extensive copy number variation (when sections of the genome are repeated in various numbers in different individuals). Individuals with few copies of the AMY1 gene have lower levels of salivary amylase and may have difficulty digesting starch into glucose. We have in a study comprising 19 subjects found a higher postprandial (after eating) glycemia in those with high AMY1 copy number compared to those with low copy number. We now intend to examine the postprandial response to two different starch doses in 60 individuals with low or high AMY1 copy number. Including outcomes such as breath analysis, microbiota and metabolites such as sugars, lipids, amino and organic acids, would give us a more detailed insight into the effect of AMY1 copy number on starch digestion and glucose metabolism. Participants will be recruited from the Malmö Offspring Study by genotype-based recall. We will also examine whether AMY1 copy number is associated with microbiota composition and metabolites among approximately 1500 individuals from the cohort to further understand the metabolic profile of those with low and high copy number. Because high postprandial glycemia is a risk factor for type 2 diabetes, this research project will hopefully contribute to more personalized prevention strategies in which glucose intolerance could be reduced by recommending specific starch intakes depending on the AMY1 copy number.