Overindulgence vs. Healthy Habits

Life expectancy based on good and bad habits can help keep things in perspective

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Veggies are good for the body. Smoking is bad. Most people have these facts down by now, but do they know how good and how bad? A math professor has simplified a way to look at how habits add or take away years of life.

“This form of communication allows a general, non-academic audience to make rough but fair comparisons between the sizes of chronic risks, and is based on a metaphor of “speed of aging,” which has been effective in encouraging cessation of smoking,” said the author.

"Don’t overindulge too much this holiday season."

David Spiegelhalter, PhD, professor of biostatistics at the University of Cambridge in the UK, has done the math on overindulgence.

For this calculation study, Dr. Spiegelhalter used a measure called a 'microlife'. This measured negative outcomes from overindulgence in 30 minute units.

This unit is based on the measure that 1,000,000 half hours equals 57 years. Dr. Spiegelhalter used demographic information from populations all over the world and over the course of many lifetimes to calculate the accuracy of a microlife.

While estimates were a little rough, for example - unknown variables in life expectancy, each unit of microlife is based on wide samples of average.

Overindulgence units of 1 microlife per day, based on previous epidemiological study averages, can be measured in:

  • Smoking two cigarettes per day (-1 microlife)
  • Smoking 15-24 cigarettes per day (-10 for men, -9 for women)
  • Consuming two extra alcoholic drinks per day (-1 microlife for every two extra drinks)
  • Eating an extra portion of red meat per day (-1 microlife)
  • Being 11 lbs. overweight (-1 microlife)
  • Watching two hours of television per day (-1 microlife)

Gains in microlives, healthy habits that prolong life expectancy, can also be measured in:

  • Taking statins for cholesterol (+1 microlife)
  • Consuming only 1 alcoholic drink per day (+1 microlife)
  • 20 minutes of moderate exercise per day (+2 microlives)
  • Eating lots of fresh produce every day (+4 microlives)

Due to multiple variables that come in to play when predicting life expectancy, these microlives are predictions based on averages, not by exact calculations.

Dr. Spiegelhalter’s calculations should be viewed as a general guide to improving prolonged quality of life by avoiding harmful behaviors and participating in healthy habits. For example, just because someone were to participate in 20 minutes of exercise per day doesn't not mean that they would have a free pass to smoke four cigarettes.

This study was published in December in the British Medical Journal.

No outside funding was used for this study. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
December 17, 2012
Last Updated:
February 9, 2013