The study involves a nutritional intervention with a controlled, double-blind, randomized, cross design. It includes 44 healthy subjects with a total duration of 20 weeks with a "wash-out/stabilization" period for 2-4 weeks before randomization. Subjects are randomized in two groups: (1) those who begin drinking 2 alcohol-free beers (33 cl each one) that are enriched in a resistant maltodextrin and isomaltulose during 10 weeks and continue drinking 2 alcohol-free beers (33 cl each one) with regular composition during the next 10 weeks following; (2) those who will follow the same previous intervention but in reverse, beginning with standard alcohol-free beer for 10 weeks, followed by resistant maltodextrin and isomaltulose-enriched beer for the remaining 10 weeks. There is a washout period between both phases to facilitate adherence to nutritional intervention, since we consider that a period of 20 consecutive weeks could be difficult to assume for the participants. Participants and the research team are "blind" to the type of beer that subjects are taking in each phase. Only one person of the company that provide beers, which does not directly participate in the clinic visits or in the analysis of the data, is aware of this information. Clinical staff performed the randomization based on a computerized method.
Among those subjects included in the study, microbiota sub-study is proposed which require a specific authorization within informed consent. Among all subjects that are included in this substudy and that have completed the whole nutritional intervention, 10 subjects (5 from each randomized group) will be selected to microbiota determination.
* Study visits:
1. Prescreening visit: Inclusion and exclusion criteria assessment and blood collection if glucose or glycated hemoglobin is not available in previous 3 months. Healthy diet and physical activity counselling is provided by a nutritionist; it should be maintained during all study. Baseline visit is scheduled in 2-4 weeks after lifestyle stabilization.
2. Baseline phase 1 visit: Clinical, biochemical, dietary, physical activity and anthropometric data are assessed. Computer-based randomization is performed. Alcohol-free beer (A or B according to randomization procedures) for the next 10 weeks is delivered to the participant who has to consume two per day. A nutritionist emphasizes healthy lifestyle counselling to the participant. A feces sample is collected if subjects accept to be included in microbiota sub study.
3. Intermediate phase 1 visit: Clinical, biochemical, dietary, physical activity and anthropometric data are assessed. Satiety after alcohol-free beer consumption is measured by a validated questionnaire. A nutritionist emphasizes healthy lifestyle counselling to the participant.
4. End of phase 1 visit: Clinical, biochemical, dietary, physical activity and anthropometric data are assessed. Satiety after alcohol-free beer consumption is measured by a validated questionnaire. A nutritionist emphasizes healthy lifestyle counselling to the participant. A wash-out period of 4-8 weeks is scheduled before the next phase start. A feces sample is collected if subjects accept to be included in microbiota sub study.
5. Baseline phase 2 visit: Clinical, biochemical, dietary, physical activity and anthropometric data are assessed. Alcohol-free beer (A or B: if subjects consumed alcohol-free beer A, he/she change to alcohol-free B and vice versa) for the next 10 weeks is delivered to the participant who has to consume two per day. A nutritionist emphasizes healthy lifestyle counselling to the participant. A feces sample is collected if subjects accept to be included in microbiota sub study.
6. Intermediate phase 2 visit: Clinical, biochemical, dietary, physical activity and anthropometric data are assessed. Satiety after alcohol-free beer consumption is measured by a validated questionnaire. A nutritionist emphasizes healthy lifestyle counselling to the participant.
7. End of phase 2 visit: Clinical, biochemical, dietary, physical activity and anthropometric data are assessed. Satiety after alcohol-free beer consumption is measured by a validated questionnaire. A nutritionist emphasizes healthy lifestyle counselling to the participant. A feces sample is collected if subjects accept to be included in microbiota sub study.
* Study variables:
* Clinical variables: Gender, age, medical records including diseases and medication, tobacco consumption and blood pressure.
* Anthropometric variables: Weight, height, body mass index, waist circumference, body composition analysis.
* Biochemical variables: Glucose, lipid and iron metabolism are assessed. Inflammatory biomarkers, including C reactive protein, are also determined.
* Microbiota: Feces samples are collected to microbiota analysis including Bacteroides, Lactobacillus, Enterococcus, Prevotella or Roseburia, among others.
* Dietary and physical activity assessment: Diet and physical activity are assessed by validated questionnaires.
