Pictured: "Dad bod" pioneer Chris Pratt

Earlier this year, the “dad bod” became a trending topic across the internet. Describing young men who are (or were) generally well built but have developed a bit of the gut associated with age and fatherhood, the dad bod sparked controversy: Do women find it attractive? Do women actually find it more attractive than a ripped physique? The jury’s still out in that regard, but researchers at the Northwestern University Feinberg School of Medicine know one thing’s for certain: Becoming a father does, in fact, lead to weight gain.

“Fatherhood can affect the health of young men, above the already known effect of marriage,” said lead author Dr. Craig Garfield, associate professor of pediatrics and of medical social sciences at Northwestern University Feinberg School of Medicine. “You have new responsibilities when you have your kids and may not have time to take care of yourself the way you once did in terms of exercise.”

However cute their pudgier dad bods may be, Garfield warns that men who gain excess weight face an increased risk of ailments like heart disease, diabetes and cancer.

The study was conducted over 20 years and included 10,253 participants. Their BMI was measured at four points in life: Early adolescence, late adolescence, their mid-20s and their early 30s. Each man was also classified as either a father, a non-resident father (a dad who didn’t live with their child) or a non-father.

Sure enough, the dad bod effect is real. On average, a six-foot man who lived with his children gained an average of 4.4 lbs, or an increased BMI of 2.6. Non-resident fathers gained less, just 3.3. lbs or a 2.0 increase in BMI. Resident fathers are more likely to spend time with their kids (as well as graze off their plates), which may explain the discrepancy.

As for the non-fathers, they seemed to elude the dad-bod’s clutches. Those men actually lost weight, an average of 1.4 lbs over the same time period. The researchers did not speculate as to why these men lost weight, but it’s fair to assume that not having children allots men more free time to exercise and likely limits the amount of tempting food available to them.

Many young fathers don’t have primary care physicians of their own. While troubling, Garfield says that pediatricians should use children’s checkups as opportunities to talk to fathers about their dad bods, especially since more and more fathers now take an active role in their child’s care.

“We now realize the transition to fatherhood is an important developmental life stage for men’s health,” Garfield said. “It’s a magical moment where so many things change in a man’s life. Now the medical field needs to think about how can we help these men of child-rearing age who often don’t come to the doctor’s office for themselves.”

Hot or not, the dad bod is here to stay.