Criticizing someone's weight may cause them to pack on more pounds, according to a recent study.

Researchers from the University of Waterloo found that women whose loved ones are critical of their weight tend to put on even more pounds.

"When we feel bad about our bodies, we often turn to loved ones -- families, friends and romantic partners -- for support and advice. How they respond can have a bigger effect than we might think," Christine Logel, who led the study, said in a statement.

For the study, researchers studied university-age women, demographic often dissatisfied with personal weight. They asked the women their height and weight, and how they felt about what they see on the scale. About five months later, they asked them if they had talked to their loved ones about their concerns, and if so, how they had responded. About three months after that, they tracked whether their weight and their concerns about it changed in that time.

"On average, the women in the study were at the high end of Health Canada's BMI recommendations, so the healthiest thing is for them to maintain the weight they have and not be so hard on themselves," Logel said. "But many of the women were still very concerned about how much they weigh, and most talked to their loved ones about it."

Overall, the women involved in the study gained weight over time. However, researchers found that if the women got the message from their loved ones that they look fine, then they maintained or even lost a bit of weight. Women who received comparatively few weight acceptance messages from their loved ones gained almost 4.5 pounds on average, whereas women who received comparatively more weight acceptance messages lost a pound.

The results showed that when women concerned about their weight heard that their loved ones accepted them as they are, they felt better about their bodies, and subsequently they did not gain like other women did.

They also found that pressure from loved ones about weight loss was not helpful for women already concerned about it. And it actually led women who weren't originally concerned about their weight to gain some weight.

"Lots of research finds that social support improves our health," Logel said. "An important part of social support is feeling that our loved ones accept us just the way we are."

The findings are detailed in the December issue of the journal Personal Relationships.