Pre-clinical studies indicate that creatine may play a substantial role in diet-induced thermogenesis and may have a profound effect on energy balance. A recent retrospective study of BAT activation on PET-CT scans in humans showed a positive association with the estimated renal creatinine clearance and BAT activation, possibly linking creatine metabolism in humans to BAT activity. In humans, so far little options are available to activate brown adipose tissue. The most potent intervention to activate BAT is via cold, which has previously been shown to have metabolic effects in humans. Provided the potential health benefits of brown adipose tissue activation in humans, and provided the role of brown fat in diet induced thermogenesis, we here aim to determine whether creatine monohydrate supplementation can increase diet-induced thermogenesis and activate brown adipose tissue in humans.

Inclusion Criteria:

• Male or female;
• 18 to 30 years of age;
• Consuming a vegetarian diet;
• BMI 20-25 kg/m2.

Exclusion Criteria:

• Not meeting all inclusion criteria;
• Non-vegetarian diet;
• Excessive alcohol and/or drug abuse;
• Significant allergies or intolerances concerning the study products;
• Participation in another biomedical study within 1 month before the first study visit, possibly interfering with the study results;
• Medication use known to hamper subject's safety during the study procedures;
• Subjects with contra-indications for MRI and/or PET-CT;
• Subjects who do not want to be informed about unexpected medical findings;
• Subjects who do not want that their treating physician to be informed;
• Co-morbidities to which the intervention or program that may pose as a complicating factor;
• Inability to participate and/or complete the required measurements;
• PET-CT scan in the last 12 months.