Pregnancy Not a Grace Period for Junk Food

August 15, 2007

LONDON -- An "eating for two" approach to junk food during pregnancy and breastfeeding may boost baby's appetite for the same and lead to obesity, researchers said.

LONDON, Aug. 15 -- An "eating for two" approach to junk food during pregnancy and breastfeeding may boost baby's appetite for the same and lead to obesity, researchers said.

In a rat study with human implications, offspring whose mothers ate foods high in fat, sugar, and salt during pregnancy and lactation had a heightened preference for junk food compared with those whose mothers ate standard chow or junk food only during pregnancy, found Stphanie Bayol, Ph.D., of the Royal Veterinary College here, and colleagues.

The young rats exposed to junk food in the pre- and postnatal period had 18% to 21% higher body mass index than those exposed only to regular chow, Dr. Bayol's group reported online in the British Journal of Nutrition.

Based on the findings, physicians should encourage healthy eating habits for pregnant and breastfeeding women to help combat the obesity epidemic, they wrote.

Evidence has been accumulating that appetite and activity levels may be "programmed" by maternal nutrition, the researchers noted, but most studies have focused on maternal malnutrition.

So, they set up a study with 42 female rats to see the effect of a variety of feeding schemes on them and on their offspring.

The rats were separated into two groups during gestation. Fourteen were fed an unlimited supply of normal rodent chow. The other 28 were given rodent chow and free access to junk food from a supermarket: cookies, marshmallows, cheese, jelly doughnuts, chocolate chip muffins, potato chips, and candy bars.

Those with access to junk food ate about 40% more food and 56% more calories every day on average than those given only chow (both P

The researchers found that young rats exposed to junk food since conception had a heightened preference for foods rich in fat, salt, and sugar compared with those given junk food only after being weaned or those exposed to junk food during gestation but not during lactation, "although all young rat offspring 'enjoyed' eating junk food and favored it over chow."

The group consistently exposed to junk food consumed significantly higher calories from junk food and 18% and 26% higher total calories, respectively, than those given junk food only after being weaned or not exposed during lactation (all P