The aim of this study is to investigate the effect of a six-week period personalised food intervention with prebiotic supplementation on intense exercise performance in healthy, recreationally active adults.

The study conforms to a randomized, single-blinded, placebo-controlled parallel study design.

a prebiotic supplement will be selected based on a participants gut microbiota. 1 sachet of prebiotic or placebo will be given twice a day over a period of 6 weeks.

Before the start of the study, a VO2max test will be performed. Subjects will bring faecal samples which is collected at home. A time to exhaustion of approximately 80% of their VO2max will be performed at baseline and after the 6 weeks intervention period.

Inclusion Criteria:

• Male or female 18 - 40 y
• BMI range 18.5 - 25 kg/m2
• Recreational active (performing non-competitive physical endurance exercise at least two times per week with a minimum duration of 60 minutes per exercise bout)

Exclusion Criteria:

• Smoking
• Performing regular resistance training (3+ times per week, carrying out progressive overload training)
• Subject following an overly imbalanced or restrictive diet as per nutritional advice
• Participants who received antibiotics in the 90 days prior to the start of the study
• Self-admitted lactose intolerance
• Administration of probiotic or prebiotic supplements in the 14 days prior to the study