Fizzy drinks can foil healthy diets

May 5, 2010

Children who drink soda are less likely to have healthy diets than their peers who don’t drink soda, according to a Penn State study. The ten-year study showed that children who drank soda at the age of 5 had diets that were less likely to meet nutritional standards for the duration of the study—until they were 15. Children who did not drink soda at age 5 also failed to meet certain nutritional requirements, but their diets were healthier. The findings were published in the April issue of the Journal of the American Dietetic Association.

The study followed 170 girls across ten years of their lives, documenting meals three times every two years. Girls classified as “soda drinkers” (those who drank roughly four ounces of soda daily at age 5) showed much lower intakes throughout the study than “non-soda drinkers” (those who had no soda intake at age 5) of fiber, protein, vitamin C, vitamin D, calcium, magnesium, phosphorous, and potassium. Additionally, the soda drinkers had much higher intake of added sugars. The study made no distinction between diet and regular soda because the “soda drinkers” drank both types. However, intake of diet soda was very low at age 5.

The difference between the two groups in nutrient intake is “not just because of what they are consuming, but because of what they are not consuming,” says Dr. Laura Fiorito, research assistant in Penn State’s Center for Child Obesity Research. Milk intake differed greatly between the two groups—soda drinkers drank far less milk than non-soda drinkers—and milk has all of the nutrients that differed between the groups (except fiber). At age 5, non-soda drinkers consumed ten to 11 oz. of milk daily, while soda drinkers had less than 7.

“Adequate nutrient intake is important for optimal health and growth,” write the authors. There are many complications that can result from the poor diets highlighted in this study. For example, low calcium intake is associated with increased risk of bone fractures, and higher added sugar intake is associated with dental problems and the development of several chronic diseases, such as type 2 diabetes.

The Institute of Medicine (IOM) recommends that girls age 14-18 have at least 65 mg of vitamin C daily. In this study, soda drinkers fell short at 55 mg daily, while non-soda drinkers exceeded the recommendation at 70.5 mg daily.

Although soda drinkers had less healthy diets, both groups failed to meet recommendations for certain nutrients, such as for calcium. IOM recommends that girls age 14-18 have at least 1,300 mg of calcium daily. At age 15, soda drinkers in the study averaged 767 mg/day; non-soda drinkers had slightly higher intakes at 851 mg/day, but were still short.

Another important finding was that both groups increased their soda consumption by age 15. However, soda drinkers were consuming nearly twice as much soda at age 15 than their counterparts (6.6 vs. 3.4 oz. daily).

Although the study has considerable implications on how beverages impact diet, Fiorito believes children may already have developed drinking preferences and patterns by age 5. “We think that the patterns develop when they are younger. Some studies show that children already drinking soda or carbonated beverages at age 2,” says Fiorito.

Parents of soda drinkers in the study had higher body mass index (BMI) than non-soda drinkers’ parents. Fiorito believes this suggests that “parents model consumption patterns for their children”—that the parents’ unhealthy eating habits not only contributed to an increased BMI, but influenced children.

There have been other studies on the effects of soda on dieting, but this is the first study to track the consumption of multiple beverages over a ten-year period: coffee/tea, soda, milk, 100 percent fruit juice, and fruit drinks (any fruit-flavored drinks with less than 100 percent fruit juice).

Other beverages have come under scrutiny in recent years for their possible negative health consequences—for example, the American Academy of Pediatrics (AAP) issued a formal statement in 2001 that recommended limits on children’s fruit juice intake. AAP has not issued any formal statement on soda, but this study provides a clear link showing that soda can deter people from maintaining a healthy diet.


Editors:Laura Fiorito can be reached at For additional information, please contact the College of Health and Human Development Office of College Relations at 814-865-3831 or