Losing Weight as a Couple: What the Research Says About Doing It Together

If your partner loses weight, your own chance of losing weight more than doubles. That is not a pep talk. It comes from a study of 3,722 couples.

Here is what the research found, what it did not find, and what it looked like when one family tried it in Phuket.

What happened to 3,722 couples?

Researchers at University College London followed married and cohabiting couples in the English Longitudinal Study of Ageing. They looked at people with an unhealthy habit at the start, such as being overweight or inactive, and asked one question: does it matter what your partner does?

It mattered a lot. The results, published in JAMA Internal Medicine in 2015:

• Weight: 26% of men lost at least 5% of their body weight when their partner also lost weight, compared with 10% when their partner did not. For women, 36% compared with 15%.
• Activity: 67% of men became more active when their partner did, compared with 26% when their partner stayed inactive. For women, 66% compared with 24%.

The authors concluded that involving partners could make behaviour change programmes work better.

One honest caveat: this is an observational study. It shows a strong pattern, not the reason behind it. Couples share kitchens, routines and calendars, but the study did not test which of those things did the work.

Does it spread to a partner who is not even trying?

A trial led by Amy Gorin at the University of Connecticut tested exactly that. It followed 130 couples for six months. In each couple, only one partner was put on a weight-loss plan, either a commercial programme or a self-guided one. The other partner received nothing.

About a third of those untreated partners still lost 3% or more of their starting weight. And the rate at which partners lost weight was interlinked: when one moved, the other tended to move with them.

The trial was funded by Weight Watchers International, which is worth knowing. It is also one trial. But it points the same way as the 3,722 couples.

What does it look like in real life?

Bill, a New Zealander living in Singapore, came to Prime Revive for two weeks. He had already done a lot on his own:

"I've been training quite decently at a gym for the last two years, lost 15kg but I was at a plateau and I just couldn't break that plateau. As a result of only two weeks with Prime, I have lost over three kgs as a whole and gained close to a kg in muscle mass."

Then he said something the research would have predicted:

"I've got my wife, my daughter and my son are coming back before the end of the year."

Bill came back with his wife Sharee and their 15-year-old daughter, and the three of them stayed for three weeks. Sharee, 48, described what she noticed most:

"What I've really enjoyed about the Prime Revive team is the coaches but also watching my daughter come into her own and just sort of fitness ability, how much it's improved since we got here. It's been a joy to watch."

"It's probably brought us closer together as a family."

And one line that sounds a lot like the 3,722 couples, from the other side:

"And also to show my husband that I can do it. And to sort of encourage him as well."

She also noticed how much the setting did on its own: "Having everything on the one strip has been great ... The amount of steps you get going up and down the street all day has definitely added to it."

Why might doing it together help?

The studies above do not say exactly why, so we will not pretend they do. What they show is that partners' changes tend to move together.

That is a reason to plan the change as a pair. If one of you is about to change how you eat, train and sleep, the person you live with is part of the environment that change has to survive. Changing it together means nobody is defending it alone. (Here is the research on environment and behaviour.)

How do couples train together at Prime Revive?

Each partner gets their own programme, built around their fitness level, injuries and goals, and you run them on one shared schedule. You train at the same times with a coach beside you, eat from the same kitchen to your own targets, and recover together.

Couples share one room, so a stay for two costs less than two single packages. Tell us you are coming as a couple when you apply, and we will price your stay for two.

If you want to see how it works, read about the couples fitness retreat in Phuket. When you are ready, apply together and a coach will write a plan for each of you.

What the research does not promise

None of this guarantees that you and your partner will lose weight at the same pace. One of you may move faster. Your results are your own, and so are your partner's.

What the evidence does suggest is simpler: when one person in a home changes, the other becomes much more likely to change too. Doing it on purpose, together, puts that pattern to work.