Taoiseach Leo Varakdar was a little bit put out to learn his metabolic age was 53, even though he only turned 40 in January.
Operation Transformation was testing celebrities 'true age' on the show by inviting them to be tested.
Metabolic age is based on our basal metabolic rate which is the amount of energy burnt per day before physical activity compared to others who share our age group.
As OT host Kathryn Thomas explains, "muscle burns more then fat, so the lower your metabolic age the fitter and healthier you are."
Stepping up to the scales, the fitness fan was sceptical commenting: "I'm definitely a kilo lighter on my scales at home, but never mind that."
When the result of 53-years-old was revealed, the 40-year-old Taoiseach said he was "surprised" to hear it.
Fellow celebs who stepped up to scales included Mícheál Ó Muircheartaigh, 88, who had a metabolic age of 73 - young enough to make him "available for the Kerry team."
31-year-old Anna Geary had a metabolic age of 16 while country singer Jake Carter, 20, scored a result of 16-years-old.
Varadkar's fellow 40-year-old Kathryn Thomas had a metabolic age of 25.