The study, published in the July issue of Obesity, set out to determine how romantic relationships affect the tell-no-lies number on the scale. Researchers tracked changes over a handful of years in the weight and relationship status of 6,949 individuals, and their findings don’t bode well for commitment. Not only are married people more likely to become obese than those who are just dating, but young people who move in with a boyfriend or girlfriend tend to pack on the pounds too.

And in a twist sure to tick off all the ladies in the house, the study notes that unmarried women who have been living with their sweeties for five years or less run a 63% increased risk of obesity. What about unmarried men? On average, they have no increased risk during cohabitation.