Through Thick & Thin: One Spouse's Weight Gain Affects Their Partner's Weight [Study]

A new study has found a refreshing way to look at how obesity happens: marriage.

The study, published in the American Journal of Epidemiology, has found that when a spouse, either a man or woman, gains a lot of weight, the other spouse is also likely to gain a lot of weight, too.

“Normal weight people whose spouses went from being normal weight to obese were more likely to become obese,” Laura Cobb, who led the study as a researcher at Johns Hopkins University in Baltimore, told Reuters via e-mail.

“This suggests that changes in one spouse are likely to also be reflected in the other spouse, likely because of similar changes in diet, physical activity or other behaviors that impact obesity,” said Cobb.

The researchers arrived at the findings after following 3,889 couples for up to 25 years, starting from the period between 1987 and 1989. After the initial exam, follow-up visits were done roughly three years apart from each, with the final fifth exam between 2011 and 2013.

At the start of the study, there were only 23 percent obese men and 25 percent obese women.

It was found that when women became obese during the period between visits, their non-obese husbands were 78 percent more likely to be obese as well.

On the other hand, when the husbands became obese, their non-obese wives were 89 percent more likely to gain a lot of weight and become obese, too.

Additionally, obese spouses were more likely to become non-obese when their similarly obese spouses lose enough weight to not be considered obese anymore. Through thick and thin, indeed.

“Having a spouse become obese nearly doubles one's risk of becoming obese,” wrote the researchers.

The researchers said that the study has some shortcomings, which include the long span of time between the fourth and fifth visits, and a large number of people who either died or left the study before the fifth visit.

“Future research should consider exploring the efficacy of obesity prevention interventions in couples,” said the researchers.

Ivanka Prichard, a weight loss researcher at Flinders University in Adelaide, Australia, told Reuters via email that for married couples, it's not unusual to have common habits that will affect their weight over time.

“Over time, similarities in diet, particularly any unhealthy aspects, may lead to weight changes,” said Prichard, who wasn’t involved in the study. “There are also a range of pressures in life that could impact this such as having children, work, shared health knowledge, time or finances.”