Everyday habits and behaviours such as eating unhealthily, drinking too much, smoking and not being active enough are responsible for around 40% of all deaths in England, it has been suggested.
This costs the NHS more than £11 billion a year.
The new 'One You' campaign from Public Health England hopes to address preventable disease in adults by urging them to take control of their health and make simple changes before it's too late.
Professor Sir Muir Gray, clinical adviser for the 'One You' campaign, said: "Many diseases that impact people’s health and shorten their active lives can be prevented.
"Currently 42% of adults in midlife are living with at least one long-term health condition that increases their risk of early death and disability.
"Although it has been customary to blame people for their ‘lifestyle’ we now appreciate that we need to take into account the environmental pressures that make it difficult to make healthy choices, having to sit eight hours a day at work for example, and then drive an hour home.
"One You is designed to help every individual identify not only their risks but also the pressures they face in their life and the stress that results, and then support them with personalised tools and advice."
According to PHE, new figures show that life expectancy at older ages is at record levels, yet many are spending their retirement living in ill health.
Currently 15 million Britons are living with a long-term health condition, yet studies show living healthily in middle age can double your chances of being healthy when you are 70.
The new campaign from Public Health England aims to help adults move more, eat well, drink less and be smoke free.
'One You' will also provide information on how people can reduce their stress levels and sleep better.
People who are interested in switching up their lifestyle can take a new online health quiz called 'How Are You', which provides personalised recommendations based on a person's results.
Professor Dame Sally Davies, chief medical officer for Public Health England, said: "It is important people of all ages feel able to prioritise their health so they can lead long and healthy lives.
"We all have the power to shape our future health by making simple and small changes now. The One You campaign acknowledges that this can be difficult and is there to help make these changes easier."
Professor Kevin Fenton, national director for the health body, said: "For the first time, Public Health England is launching a campaign that talks to adults directly about all of the things they can do to improve their health.
"The scale of the campaign is unprecedented and includes new public and commercial partnerships with Asda, Slimming World, BBC Get Inspired and the Ministry of Defence.
"We want everyone across the country to know that it is never too late to get your health back on track."