Inclusion Criteria:  Healthy adolescents Aged 14-18 years Normal weight (BMI between 15th and 85th percentile for age and gender) Minimum weight of 45kg Regular sugar consumption >25g/d  Exclusion Criteria:  Severe acute or chronic diseases Pregnancy Regular intake of prebiotics Regular intake of probiotics Regular intake of pro-/prebiotic foods Antibiotics cure within 3 months preceding the present study Substance abuse Inability to follow procedures due to psychological disorders or insufficient knowledge of project language (German) Participation in another study with investigational drug within the 30 days preceding and during the present study. Pre-existing regular consumption (>1/week) of erythritol Fructose-intolerance Pre-existing diet (vegetarian, vegan, gluten-free, lactose-free, caloric restriction, etc.)