Going on a Diet With Your Partner Probably Won’t Go So Well

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Couple sitting in diner with doughnuts and fruit, portrait
Photo: Annabelle Breakey/Getty Images

After gorging on a holiday meal and leftovers recently, my partner and I have completely obliterated our pre-holiday dieting goals. I generally do well with controlling my food portions, which is admittedly hard to do given the fact that portion sizes have increased 700 percent inside and outside the home over the last 30 years. During the holidays, however, I give myself license to eat a little more because the extra serving of sweet potatoes and pumpkin pie is just too good. It is just once (or twice) a year, right? The holiday meal may not have been the real problem, though; the main culprit for me was likely the larger portion sizes consumed on leftovers while family was still visiting. 

Coincidentally, I just published a paper with some of my colleagues on how confident people feel about controlling portion sizes. We created a survey that measures how much self-efficacy, or confidence people have in controlling their food portions. We asked people how much they agreed with statements like, When eating out with friends, they finfluence how much I eat, and I feel confident that I can leave food on my plate if I think a serving size is too large. This survey is unique in that it measured not only someone’s belief that they could control their food portions while alone, but whether they could also do it in the presence of others. 

We found that women are less confident than men in their ability to control their portions, and women judge their food portions to be larger than men do, likely owing to the fact that women are generally more concerned with their weight than are men. In my case, this was true, as I felt much less confident about being able to limit my portions than did my partner over the holiday, particularly during meals when my mother was present. 

We also found that among 50 overweight, romantic couples who made New Year’s resolutions to lose weight, the more successful a partner was at restricting his or her diet and eating healthier, the less confident the other partner was in controlling their own food portions. Why might this be the case? Many factors contribute to why people deviate from their weight-loss goals, and the ability to regulate portion sizes is a critical piece for solving the weight-loss puzzle. When people strive to reach a goal, being close (in this case, romantically) with someone who is successfully reaching the same goal can make the other partner less confident in their own efforts to reach the goal. You heard that right: People feel less confident achieving their goals when they see others succeeding at the same goals. 

As I reset my diet and exercise goals for the next holiday, the take-home lesson is to set my own goals and not compare my progress with my partner. Easier said than done when we eat together as a family regularly, but nonetheless important to at least consider so that I do not let his progress undermine my own efforts. 

This post was first published on Science of Relationships