Explainer: Leo Varadkar is 40 but has a metabolic age of 53 - why is that and how can he improve it?
The Taoiseach questioned the science but was he grasping at straws?
Metabolic testing is widely available at gyms, universities and medical clinics - but just how accurate is it and will the data help you lose weight?
Taoiseach Leo Varadkar (40) was "surprised" to learn on Operation Transformation on Wednesday that he has the metabolic age of a 53-year-old.
The Fine Gael leader is a lover of running and has lost a substantial amount of weight in recent years. So why did his result turn out the way it did?
Niall Moyna, professor of health and human performance at Dublin City University, explains.
What is your metabolic age?
It's a term used to describe overall fitness and metabolic activity. The amount of energy the body needs to function while resting for 24 hours is known as the basal metabolic rate. Metabolic age compares your current resting metabolic rate to what it should be for your chronological age.
How is it measured?
There are a number of ways to test it. The method used on Operation Transformation involved measuring the electrical currents in your body on a scales. They took the person's age, gender, body size and the amount of fat and lean tissue they have into consideration. The scales then assess how easy it is for the currents to travel throughout your body. Leo Varadkar's result means he must have more fat than muscle, as fat impedes electrical currents from travelling and that's why he had a higher metabolic age. He's also very tall, so might not have realised how much excess weight he is carrying.
Is it 100pc accurate?
It's a good way to estimate whether you need to lose weight and improve muscle mass, but it's not the gold standard test. Ideally, you should be resting, shouldn't have exercised for 24 hours and shouldn't have eaten for 12 hours before doing a metabolic test, as this can influence your result somewhat. The best way to measure metabolic rate is by lying in a lab for 30 minutes and measuring your oxygen uptake.
How does it differ from BMI?
Body Mass Index doesn't tell you what's muscle or fat. Some athletes are calculated as being overweight or obese because they've tremendous amounts of muscle, which is heavier than fat. The metabolic age test differentiates between muscle and fat.
How do I improve my metabolic age?
The best way is to build up muscle by exercise and reduce fat through diet. Those with more muscle have a faster metabolism. Think of a Ferrari and a Mini Cooper stopped at a red light. The Ferrari is burning a lot more petrol because it has a bigger and stronger engine. Similarly, a person with more muscle is going to burn more calories when at rest. The best type of training to improve muscle mass is endurance and resistance. Diet also has a profound effect. If you're consuming more calories than you're expending, you're going to have more fat and therefore a slower metabolism.