British Prime Minister Boris Johnson revealed Tuesday he was obese when he contracted the coronavirus earlier this year, but after losing weight said he now felt much better.

The 56-year-old spent three nights in intensive care in April after contracting COVID-19, and there have been swirling questions about his health ever since.

"I am fitter than I was before, it may irritate you to know," he said when asked by a reporter about his health following a speech on education.

"I am fitter than a butcher's dog, thanks basically to losing weight."

"When you reach 17 stone six (around 111 kg, 244 pounds) as I did, at a height of about five foot 10 (around 1.78 meters), it's probably a good idea to lose weight, so that's what I've done. And I feel much much better."

An online calculator provided by the state-run National Health Service (NHS) suggests that a man with Johnson's age, weight and height would have a body mass index (BMI) of 34.9 – classing him as obese.

It is not the first time Johnson has boasted about his health, using a newspaper interview in June to make the "butcher's dog" analogy and even doing push-ups to prove his fitness.

But the issue has returned as a talking point amid anxiety among his Conservative lawmakers over his handling of a new uptick in coronavirus cases.

The outbreak has so far killed 42,000 people in Britain – the worst toll in Europe.

Johnson has recently been spotted running with a personal trainer in a park near his Downing Street office. As London mayor between 2008 and 2006, he was a keen cyclist.