Aug. 15, 2007 -- Eating lots of junk food during pregnancy or while breastfeeding may make childhood obesity more likely, a new study suggests.
The pregnancy diet study was conducted in rats, not people. But the researchers argue that their findings show that mothers may pass their junk food diets on to their offspring and increase their obesity.
The researchers included Stephanie Bayol, PhD, and professor Neil Stickland, PhD, of London's Royal Veterinary College.
"This study shows that a maternal junk food diet during pregnancy and lactation may be an important contributing factor in the development of obesity," they write in the British Journal of Nutrition.
The researchers also put it more bluntly, stating that women shouldn't see pregnancy and breastfeeding as "an opportunity to overindulge in fatty, sugary, and salty foods on the misguided assumption that they are 'eating for two.'"
Pregnancy Diets Tested
The researchers studied pregnant rats that only ate regular chow or ate a "junk food diet" during pregnancy and/or while breastfeeding.
The junk food diet included ordinary rat chow and biscuits, marshmallows, cheese, jam, doughnuts, chocolate chip muffins, buttery pancakes, potato chips, and caramel or chocolate bars bought at a British supermarket.
The pregnant rats on the junk food diet made a beeline for the junk food, turning up their noses at the healthier rat chow they were also offered.
After the rats gave birth, the researchers followed the mama and baby rats for 10 weeks.
As the baby rats nursed, their mothers either ate plain chow or the junk food diet. When the babies weaned, they could choose between ordinary chow or junk food, and eat as much as they liked.
The weaned rats all had a taste for junk food, regardless of what their mothers had eaten during pregnancy.
But the baby rats that ate the most junk food -- and gained more weight -- were those with mothers who had feasted on junk food during pregnancy and while breastfeeding.
That exaggerated taste for junk food "might make it more difficult to encourage healthy eating habits and thereby control obesity and related problems," the researchers conclude.