In a video posted to Twitter on Thursday, Mr Johnson said he is “doing all I can to lose weight”, which has involved early-morning runs and fewer carbohydrates, avoiding chocolate and steering clear of “late-night cheese” snacks.
“I’ve been doing a lot, in fact, everything I can, to lose weight and to feel fitter and healthier,” Mr Johnson said.
“The result is I actually have lost some weight, quite a lot by my standards, and I feel much more energetic, I feel full of beans and I thoroughly, thoroughly recommend it,” he said.
Downing Street has suggested that Mr Johnson has lost around a stone, with Press Secretary Allegra Stratton saying: “I think it’s 14 pounds he has lost, which is a stone. I think he might have lost a bit more than that, I think he is being modest,” according to PA. “He takes his diet very seriously,” she said.
“I know there are many people in the same sort of position as I am, and I was, who want to lose weight. That’s why we’re investing now in that whole national objective,” Mr Johnson said.
On Thursday, the government introduced a £100m-package aimed at helping address obesity, which includes more more than £70m to make weight-management services more accessible.
The investment is expected to enable up to 700,000 adults to access support through the NHS and councils to help them lose weight. Meanwhile, another £30m will be dedicated towards helping people maintain a healthy weight.
The government is also looking into the possibility of a “fit miles” programme that would use rewards to encourage the public to make healthy choices.
Sir Keith Mills, who is behind the Airmiles and Nectar points programmes, has been appointed to advise on developing the “fit miles” scheme.
In a statement published by the Department of Health and Social Care, Mr Johnson noted that “being overweight increases the risk of becoming ill with Covid”.
“If we all do our bit, we can reduce our own health risks – but also help take pressure off the NHS,” he said.
The prime minister launched an effort to promote healthy choices after his own bout with Covid.
He has previously said he takes his hat off to vegans, but called the lifestyle choice “a crime against cheese-lovers”.