How many more years will I live if I make healthy choices?

Jim Pollard answers the million dollar question - bet your shirt on 14.

We're asked all the time to make choices in life. Most of us try to base the choices we make on sound evidence.

For example, you're more likely to back this season's champions Manchester United to win the premier league next season than newly-promoted Burnley. The evidence? Eleven-times winners of the Premier League, United have done it all before whereas Burnley, despite a proud history (they last won the league in 1960), haven't been in the top division for over 30 years. The numbers are very much on United's side.

This evidence is reflected in the odds that the leading bookies will quote you on United and Burnley. United are 9-4 to win the title, Burnley 5000-1.

Now, the odds on you getting cancer at some time in your life are just slightly longer than those on United winning the league next season: 3-1. That ought to make us all sit up and take note but until recently there was a big problem when it came to making health choices. We just didn't have all the numbers we needed to weigh up the evidence.

Health campaigners simply couldn't answer the question:  how much will doing all this healthy stuff really help?

They can now. In 2008 we got the results of a study that began in the early 1990s in Norfolk, England. The study followed 20,000 people over 45 for a decade. The researchers gave participants one point for:

• not currently smoking,
• drinking less than 14 units of alcohol per week
• eating five servings of fruit and vegetables each day and
• not being inactive (that is, taking just half an hour basic exercise a day).

The key number here is four. Those who did all four of the above were four times less likely to die than those who did none of them.

To be more specific, a 60-year-old person with a score of zero had the same risk of dying as a 74-year-old with the full four points. In other words, researchers were able to finally answer the question: 'how much good will healthy living really do me?'

 The answer is: it will add about 14 years to your life. Fourteen years is a lot. Three World Cups, three presidential terms, 14 pairs of socks for your birthday.

OK, you might not live to see Burnley win the league but at least you might be around when United boss Alex Ferguson finally hangs up his hair-dryer.

Another way of looking at it — as they did in a 40 year study of 6,000 Americans of Japanese origin published in 2006 - is that if in mid-life you're basically doing the healthy things you have a 60% chance of survival to 85. (In raw odds terms, 6-4 on.)

But what if you're not doing the healthy things? (The healthy things in this study, by the way, were the usual suspects: not being overweight, having a balanced diet, not smoking, not drinking too much, taking exercise and being married.)

The more of these you failed on, the less likely you were to make it into old age and the difference is far, far more than you might imagine.

If, at age 55, you've got the full set of bad habits (smoking, boozing, weight-problems etc) you have just a 1 in 10 chance of reaching 85. Any gambler will tell you there's a big difference between 6-4 on and 10-1.

Let's put it this way, 6-4 on is about the odds on one of the top three teams in the premier league this year winning it next year: Manchester United or Liverpool or Chelsea - as close to a sure thing as you can get in the lottery of life. 10-1 is the odds on Arsenal, the team who finished back in fourth this year. Ok, it's not as reckless as a bet on Burnley but you get the point.

In the classic The Hitch-hiker's Guide to the Galaxy, Douglas Adams's answer to the meaning of life, the universe and everything is 42. Actually, it is exactly one-third of that: 14. Now you have all the numbers you need to make your own health choices. Like Cruyff and Ginola, bet your shirt on 14. 

A version of this article first appeared in Jim Pollard's book The User's Guide to the Male Body.