Video transcript

Couples who have been together for some time are known to have a degree of mirroring in their weight changes over the year. Part of this is from the home environment they share, but researchers are also wondering if there could be some psychological factors at play. If so, this could be turned to the advantage of both in the aim of losing weight.

Studies that observe weight changes in couples seem to show that if one person actively loses weight, the weight loss may ‘spread’ to the partner. This is called the ripple effect. Taking the observational research a step further, a United States research team designed an active intervention study to see if the ripple effect can be replicated in a controlled experiment.

Coupling up for weight loss

For the new research, a group of 130 cohabitating couples were randomised to either an active weight loss intervention (in this case the Weight Watchers program) or to a self-guided control group for 6 months. The important part of the study was that only one partner was allocated to the control or intervention group; the person’s spouse was not actively taking part in any activity.

Unsurprisingly, people actively taking part in the weight loss program lost more weight compared to people randomised to the control group, although both groups did lose weight. The real meat of the study though was all about the spouses. How did their weight change? Partners of both those who were in the weight loss program and the control group also enjoyed some degree of weight loss (about two kilograms) with little difference between the groups.

It seems that when one member of a couple committed to losing weight, the chances were good that their partner would lose some weight too, even if they were not actively participating in a weight loss intervention.

Another interesting finding was that the rate at which couples lost weight was linked. If one person lost weight at a steady pace, so too did the spouse. Likewise, if weight loss was a struggle for one person, their partner struggled too.

Implications

Losing weight does not have to be a solo affair. When a person commits to positive changes in their eating and exercise habits, this can have a positive flow-on effect to their partner. Exploring ways to actively involve spouses in weight loss treatments may improve the reach and cost-effectiveness of weight management programs.