Claire Byrne is the latest public figure to face off against the now-dreaded metabolic age test, following in the footsteps of Taoiseach Leo Varadkar who was shocked to learn his "true age" after completing the test on last week's Operation Transformation

The nation collectively cringed when Varadkar, the 40-year-old devotee of triathlons and his strict meat-free diet, was found to have a metabolic age of 53, signifying that the former minister for health and sport isn't as fit as he thought. 

Believed to show your "true age", metabolic age measures your overall health and fitness levels and is calculated based on our Basal Metabolic Rate, which is the amount of energy or kilocalories we burn a day before activity, compared with other people in our age group. 

Claire Byrne predicted a metabolic age of 53

Using a specially designed weighing scales, metabolic weight is measured according to age, weight, height, activity level, body fat mass, and lean body mass and monitored when the body is in as neutral a state as possible, so usually after 12 hours of fasting. 

It's typically believed that lean muscle will burn more fat, so the more resistance training or strength exercises you do, the lower your metabolic age will be. 

No doubt intrigued, Byrne was the latest to put herself to the test, against her "better judgement", and went one step further: doing so live on air from her studio. 

"I didn't want to do this, I refused when I was first asked, but you know what? It's a bit of craic", said the presenter, approaching the machine.

"Maybe I just won't tell them if it's really bad."

Joined in the studio by Prof Niall Moyna of, who explained where Varadkar may have gone wrong last week, he explained that the machine would pass a small electrical current through Byrne's body and this would help calculate the composition of muscle and fat.

The machine measures body fat by passing a small current through the body

"See I don't lift weights, I don't do any of that ... it's going to be awful", the 43-year-old predicted, as she said she doesn't do any resistance training whatsoever. 

"So if I get 53 I'll be happy because I think that's what I deserve", she laughed. 

Telling the presenter to close her eyes, Moyna announced that her metabolic age is 28, a brilliant result that Byrne was evidently chuffed with. 

"I'm so relieved, so relieved," she said. 

Due to her good fitness routine and balanced diet, Moyna said that Byrne's body fat was likely lower than she expected.  

Spare a thought for poor Leo, so.