The study evaluates the acute effects of Helichrysum italicum on resting energy expenditure and substrate oxidation in humans. The resting energy expenditure and substrate oxidation will be measured by indirect calorimetry at baseline and after ingestion of either Helichrysum italicum infusion or hot water.

Bioactive compounds found in medicinal plants and plant extracts, such as polyphenols, represent the oldest and most widely used form of alternative or complementary treatments for the prevention and management of obesity. Their consumption is currently increasing in the population due to the high cost, potential adverse effects and limited benefits of currently available pharmaceutical drugs. Helichrysum italicum is a mediterranean plant with promising nutraceutical activities. The plant is known as a rich source of biologically active compounds such as polyphenolic antioxidants, which are recognized in the prevention of various non-communicable chronic diseases. However, most of its traditionally claimed uses have not yet been scientifically proven.

The proposed study will investigate the acute effect of Helichrysum italicum infusion on resting energy expenditure, substrate oxidation, respiratory quotient and blood pressure in a pilot study of 11 male adults. It will be designed as a crossover study. Half of the participants will consume the Helichrysum italicum infusion and the other half will consume hot water. After seven days of washout period the participants will consume the alternate beverage.

Inclusion Criteria:

• healthy, weight-stable (±3 kg in the last 3 months), normotensive, non-smokers, no use of dietary supplements or frequent use of medication and no known metabolic disorders.

Exclusion Criteria:

• females, smoking, medications, dietary supplements, metabolic diseases, hypertensive