If you were overweight or obese as a young adult, but have managed to gradually lose some weight as you’ve progressed to late adulthood, then you’ve reduced your risk of developing precancerous polyps by almost half.
This is the finding of an unusual new study that tracked precancerous risk and weight loss (and weight gain) over the long term.
The weight loss required to get this significant benefit wasn’t huge: About a kilo a decade.
By the numbers
People who gradually lose weight during a 50-year period will reduce their risk for developing precancerous growths, or adenomas, by 46 per cent, according to investigators from the University of Maryland School of Medicine.
Weight loss among those who were overweight or obese at age 20 get an even better result, a more than 60 per cent reduction in risk.
On the flip side, people who experience weight gain greater than 3kg over five years increase their risk of developing these precancerous polyps.
Where the data came from
The big-picture analysis was achieved by looking at data from a large randomised US study called the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening trial.
In the new study, researchers examined weight change – both weight gain and weight loss – over three periods of adulthood in relation to colorectal adenoma.
They evaluated 17,629 PLCO participants who had available weight data, had reported no history of colorectal polyps or other colon conditions, had received a negative result (no polyps or cancer) on a screening test called flexible sigmoidoscopy at the start of the trial, and had received a follow-up sigmoidoscopy three or five years later.
The take-home message here is that any weight loss, over any period, is probably going to reduce your risk of developing these polyps.
“Our research suggests that avoiding weight gain in adulthood may help lower an individual’s chance of developing colorectal adenomas, which may in turn reduce the risk of developing colorectal cancer,” said the senior author, Dr Kathryn Hughes Barry, Assistant Professor in Maryland’s Department of Epidemiology and Public Health.