1. GENERAL INTRODUCTION. 2. SAMPLING PROTOCOL. 3. REGULATORY ASPECTS. 4. TRACEABILITY OF SAMPLES. 5. CASE REPORT FORM. 6. EUROPEAN SOCIO-ECONOMIC STATUS QUESTIONNAIRE (SESQ), GENERAL QUESTIONNAIRE (GQ), AND QUESTIONNAIRE FOR PARENTS (QP). 7. EWI-C EATING BEHAVIOUR - WEIGHT. 8. NKT-C NUTRITION KNOWLEDGE. 9. FOOD CHOICES AND PREFERENCES. 10. DETERMINANTS OF HEALTHY EATING AND PHYSICAL ACTIVITY. 11. HELENA - DIAT. 12. PHYSICAL ACTIVITY QUESTIONNAIRE. 13. PHYSICAL ACTIVITY ASSESSMENT - ACCELEROMETRY.14. PHYSICAL FITNESS ASSESSMENT. 15. ANTHROPOMETRY AND BIOELECTRICAL IMPEDANCE ASSESSMENT. 16. AIR DISPLACEMENT PLETHYSMOGRAPHY USING BOD POD. 17. MANUAL FOR BLOOD SAMPLING. 18. MANUAL FOR STRESS ASSESSMENT. 19. LIST OF AUTHORS