• Posted July 31, 2026

What Dad Eats Before Conception May Influence Baby's Health

When it comes to preparing for a healthy pregnancy, the focus is usually on moms. But new research suggests dads' nutrition plays an important role, too.

"Maternal nutrition and health before, during and after the baby's birth have always received attention, but little is said about the role of the father's diet," said study author Daniela Sartorelli, a professor of medicine at the University of São Paulo in Brazil. "Our study shows that it also matters a great deal for the baby's health."

In a study of 43 families, researchers found that the more ultra-processed foods fathers consumed before conception, the higher their babies' birth weight and the greater the accumulation of fat in the thighs and around the waist at birth.

Higher birth weight and elevated body fat early in life are considered risk factors for cardiometabolic diseases in adulthood.

Researchers believe diets high in ultra-processed foods may trigger inflammation in the body, affecting sperm quality and changing how certain genes are expressed before they're passed to a baby.

One gene highlighted in the study, IGF-II, is inherited exclusively from the father and plays a key role in fetal growth.

A father's eating habits may change how that gene behaves, researchers said, potentially influencing fetal development.

Moms' diets also mattered, but in a different way. Mothers who ate more ultra-processed foods early in pregnancy tended to have babies with lower birth weights, shorter lengths and smaller head circumferences.

Researchers say the findings reinforce the importance of including fathers, alongside mothers, in health and family planning guidance.

The study was published in the July issue of the journal Nutrition Research.

More information

The Bump has more about ultra-processed foods and pregnancy.

SOURCE: HealthDay TV, July 31, 2026