Sir Keir Starmer is preparing a series of 'nanny state' interventions in public health as he tries to save the NHS from collapse.
The government on Thursday promised a "prevention revolution" - saying the measures would be bold, controversial and not universally popular.
Ministers have announced plans to introduce a ban on junk food advertising after 9pm by October 2025, as well as a total ban on paid online advertising.
The Prime Minister has also promised a raft of further measures as part of efforts to move 'from disease to prevention' of ill health.
A ban on energy drinks for children under 16 is expected to be introduced in parliament next month, with supervised tooth brushing for pre-schoolers due to be introduced later this year.
In a speech on the future of the NHS, Sir Keir said: "I know some of the prevention measures will be controversial, but I am prepared to be bold, even in the face of loud opposition. So no, some of our changes will not be universally popular, but I will do the right thing for our NHS, our economy and our children."
Meanwhile, Health Minister Andrew Gwynne said the government would honour its election manifesto and restrict junk food advertising on TV and online.
In a written statement to MPs, he said: "The country wants our broken NHS fixed. Our health mission makes clear that this requires a prevention revolution, tackling the causes of preventable disease and reducing the demand on health services."
Sir Keir has already said the government is considering introducing a ban on smoking in pub gardens. The measure would complement measures to make it illegal for anyone born after 2009 to ever buy cigarettes, which were originally planned by the previous government.
The Tobacco and Vaping Bill, which is also expected to ban disposable vapes as part of efforts to tackle "the scourge of teen vaping," is expected to be introduced into parliament within weeks.
Starmer: I know the measures will be controversial
On Thursday, Sir Keir said ministers were considering further measures to tackle obesity and unhealthy diets, as part of a 10-year plan for the NHS due to be implemented next year.
Asked what measures were being considered, the prime minister said: "We need to move to the preventive model. I am absolutely convinced of that and that will be part of the 10-year plan."
Speaking at the King's Fund annual conference in London, Sir Keir said he was shocked to learn that tooth extractions are the main reason children aged six to 10 are admitted to hospital.
He said: "That is a disease that is very easily preventable, but of course you also need diet and a healthy lifestyle.
"We're going to have to get into that space because we're going to have more and more conditions, we're going to live longer. That's good, but just throwing more and more money into the NHS as it is now is not going to work. We also need preventive measures and we'll set those out in the 10-year plan.
"Of course I know some of them will be welcome and I know some of them will be controversial. They always are. But unless we change the model, I don't think we can get the change we need."
Before the election, Labour announced plans for supervised toothbrushing for three- to five-year-olds during breakfast clubs.
The schemes are expected to be rolled out in the most deprived areas later this year.
Earlier this week, Mr Gwynne said measures to prevent disease were "at the heart" of the Department of Health and Social Care's bids for Treasury spending.
The minister said he hopes "many public health projects" will be included in the upcoming spending review.
Last month he announced plans for workplace MOTs as part of efforts to tackle rising heart disease among middle-aged men.
Ministers have also pledged to give local authorities more powers to crack down on junk food outlets and restrict their location near schools.
Recently, the Ministry of Finance discussed the introduction of new taxes on foods with a high salt or sugar content.
But Wes Streeting, the health secretary, told LBC there were no plans for such taxes. He said: "The reason we are reluctant to go down that route is because there is a cost of living crisis at the moment."
Speaking at the King's Fund, following the publication of an independent inquiry into the NHS which declared the situation "in critical condition", Sir Keir said that without reform there would be no more money for the NHS.
And he promised to crack down on any unions that stood in his way. He said he had faced "a lot of resistance" to changing the Labour Party, but he was pushing ahead.
The comments came after Prof Sir John Bell, a leading scientist, said doctors at the British Medical Association had been "a major barrier to health reform".
The Prime Minister said: "Reform doesn't just mean investing more money. Of course a Labour government, even in difficult financial circumstances, will always make the investment in the NHS that is needed, but we have to fix the pipes before we turn on the taps.
"So listen to me when I say this: no more money without reforms."
NHS weakened by cuts, report finds
The Health Secretary promised to "get tough on ill health, get tough on the causes of ill health", as he embodied the spirit of New Labour in the House of Commons.
Mr Streeting gave a nod to Sir Tony Blair's mantra of "tough on crime" as he outlined a "national mission" to improve health services across the country.
Lord Darzi's inquiry into the NHS found that the health service had been "seriously weakened" in the decade before the pandemic, with both austerity funding and the 2012 Conservative reforms of the health service blamed.
"In other words, it's not just that the Conservatives didn't fix the roof while the sun was shining. They doused the house with petrol, left the gas on and Covid lit the match. That's why today's waiting lists are up to 7.6 million."
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Victoria Atkins, the shadow health secretary and Streeting's predecessor, said MPs should stop "political posturing and start talking constructively about the future of the NHS".
The Conservative MP defended the previous government's record, which included working with NHS England to announce a productivity plan, and said her party had not sought to misrepresent the problems facing the NHS.
She said: "We on this side of the House have never pretended that everything has been resolved, we have never pretended that we have a monopoly on wisdom, or that there are easy answers to the difficult challenges that face us."