Weight Watchers has released the findings of a new study in partnership with the University of Connecticut which identifies weight loss ripple effect within couples.

The study tracked the weight loss progress of 130 couples over six months. The researchers found that when one member of a couple commits to losing weight, the chances were good the other partner would lose some weight too, even if they were not actively participating in a weight loss intervention.

In the study, approximately one third of the untreated partners lost 3 percent or more of their initial body weight after six months despite not participating in any active intervention.  A three percent loss of body weight is considered a measurable health benefit.

The study’s lead investigator, UConn Professor Amy Gorin, calls it a “ripple effect.”

“When one person changes their behaviour, the people around them change,” says Gorin, a behavioural psychologist. “Whether the patient works with their healthcare provider, joins a community-based, lifestyle approach like Weight Watchers, or tries to lose weight on their own, their new healthy behaviours can benefit others in their lives.”

The study, published in the US peer-reviewed medical journal Obesity, also found that the rate at which couples lose weight is interlinked. In other words, if one member lost weight at a steady pace, their partner did too. Likewise, if one person struggled to lose weight, their partner also struggled.

Commenting on the findings, Zoe Griffiths, Head of Programme and Public Health at Weight Watchers said:

“We have helped millions of people lose weight, so it’s great to see the positive impact Weight Watchers can have not only on the individual but on their partner, or on a group too – the more weight you lose, the more they lose too. This study truly does demonstrate the power of support and that’s what Weight Watchers is about. At Weight Watchers we pride ourselves on equipping our members with the skills and tools they need to be the healthiest, happiest version of themselves and with so many people joining and loving the new programme, WW Flex, #theflexeffect really is spreading across the nation!”

Previous findings of a weight loss ripple effect were limited to patients who participated in closely monitored, clinic-based interventions and those who had bariatric surgery.  Most of those studies relied on couples self-reporting their weight loss, raising the possibility of error.

The Weight Watchers and UConn study is the first to use a randomised, controlled design to look at couples’ progress in less structured and widely available weight loss programmes. Researchers recorded objective measurements of participants’ weight and examined couples’ weight loss trajectories over time.

Couples, a term used for cohabitating participants regardless of marital status, were assessed at three and six months.

The couples were divided into two groups. In one group, one member of the couple was enrolled Weight Watchers, which provided in-person counselling and online tools such as an app and bar-code scanner, to assist with weight loss. In the second group, one member of the couple received a four-page handout with information on healthy eating, exercise, and weight control strategies (e.g. choosing a low-fat, low-calorie diet, portion control). Contact with those individuals stopped with the handout.

The results showed that the untreated partners of both those who tried losing weight on their own (the pamphlet recipients) and those who were Weight Watchers members also exhibited weight loss at three and six months.

The findings could add a new dimension to national guided weight loss programmes that have traditionally targeted individuals seeking a healthier lifestyle.