Epidemiological studies have indicated a positive health impact of coffee. Nevertheless, intervention studies testing the effect of daily coffee consumption over a longer period are lacking so far. Moreover, there is a lack of knowledge about the properties of different coffees and their influence on weight development. Therefore, we tested the effect of two coffees differing in their alkyl pyridine content over a period of 3 months on weight development.

Participants were randomly associated to two groups, a test coffee group and a control coffee group. After coffee abstinence of 1 months, participants in both groups got a coffee machine and coffee pads for three months. Clinical data have been assessed before and after coffee abstinence and after 3 months of coffee consumption.

Inclusion Criteria:

• age 18-69 years
• BMI ≥27 kg/m2
• coffee consumption of ≥3 cups per day

Exclusion Criteria:

• new diagnosed type 2 diabetes during the last 6 months
• severe diseases with hospital stay during the last 3 months
• change of body weight of more than 2 kg per week during the last 4 weeks
• smoking cessation during the last 3 months or planned during the study
• acute infects
• chronical diseases with except of type 2 diabetes mellitus
• regular pharmacological therapy with except of oral antidiabetic medication or contraception
• lack of contraception in women
• breastfeeding
• physical activity of more than 1 hour per day