Healthy behaviours increase health outcomes regardless of weight

Healthy Lifestyle Habits and Mortality in Overweight and Obese Individuals

Eric M. Matheson, Dana E. King and Charles J. Everett, 2012 – full study

What’s it about?

The researchers were investigating healthy lifestyle habits and mortality in people who had a BMI which fell into the “overweight” or “obese” category.

Who took part?

11,761 adults (21 years+) were selected from the National Health and Nutrition Examination Survey III. Participants were followed for 170 months on average.

How was this studied?

The researchers considered four healthy behaviours that were recorded in the survey:

  • eating 5 or more fruits and vegetables daily
  • exercising regularly – more than 12 times a month
  • consuming alcohol in moderation – up to one drink a day for women, and two for men
  • not smoking

Death rate was determined by comparing participant results to the National Death Index.

What was found?

I think this graph says it all:

(source)

Generally, risk of death was reduced each time another healthy habit was introduced (excluding the one increase from zero to one healthy habits in BMI category 18.5 to 24.9).

For people who engaged in all four healthy behaviours, mortality was near enough the same across all BMIs.

Having a BMI of 18.5-24.9 is considered to be a “normal” range, however people of any BMI who take part in all four healthy behaviours have half the risk of “normal” BMIers who do not take part in any.

The bottom line:

Healthy lifestyle habits are associated with a significant decrease in mortality – regardless of BMI. For those who want to improve their physical health, it is important to take part in healthy behaviours, even if this does not result in weight change.

Relying on weight to determine health may lead people of lower BMI to feel that these behaviours are less relevant to them, and cause health care providers to overlook lifestyle habits in these patients. On the other hand, this leads heath care providers to focus on the weight loss of high BMI patients as a marker of heath. It would be more useful to consider these four behaviours, and encourage people of all BMIs to adopt a healthy lifestyle.