A recently concluded research study shows evidence that drinking soda can cause obesity.

"The links between soda intake and obesity that have been suggested by researchers are related to the calorie content of soda," Julie Flood (graduate-integrative biosciences) said. "Soda intake in the U.S. has increased in parallel with obesity rates."

Since 1980, Americans have been consuming high fructose corn syrup, which is the main ingredient in soda.

This is when the obesity epidemic started, Dorothy Blair, assistant professor of nutrition, said.

High fructose corn syrup causes obesity because Americans are consuming more calories than ever before, Blair said.

Flood said that essentially, calories from soda add to the total daily calorie intake.

Potentially hundreds of extra calories are added onto the daily intake of those who drink several servings of soda each day in addition to the daily diets.

Flood is studying a similar area.

Her research has found that as a person increases the portion size of a beverage served, the amount of beverage he or she will consume increases significantly.

Her research also found that when people drink regular soda or when they drink larger portions of it, they don't decrease how much food they eat. Therefore, they consume more overall calories when they are drinking soda, she said.

"Drinking soda in moderation can be healthy, but the focus should be on smaller portions and non-caloric drinks like water or diet drinks," Flood said.

Consuming soda contributes significantly to empty calories, said Melissa Martilotta, director of the nutrition clinic on campus and a nutrition instructor.

"For example, regular soda has about 80 calories per 6 ounces.

However, the average serving size at a fast-food restaurant is about 24 ounces. That is 320 empty calories. Five hundred extra calories each day for seven days can add a pound of fat to the body," she said. Soda isn't the only beverage that can cause obesity. Sweetened teas, fruit drinks and flavored coffees can also cause obesity, Martilotta said.

These drinks can cause obesity because they are made up of almost pure sugar.

"Consumption of higher caloric-content foods are more likely to result in the overconsumption of calories, which is the condition needed to gain weight," said Evan Pattishall, University Health Services clinical director.

Although lifestyle can contribute to obesity, genetics also can cause it.

Obesity can be prevented in most people by a combination of good dietary choices and exercise, he said.

Pattishall said obesity is usually defined as having a body mass index (BMI) of more than 30. The BMI is not accurate in all people, so for some, percent body fat is a better indicator of obesity. Obesity results in a greater likelihood of developing cardiovascular disease, hypertension, stroke, gallbladder disease, arthritis, respiratory conditions, cancer and diabetes, Pattishall said.

People at any age can develop obesity. The younger it develops, the more likely it is that a person remains obese and the greater likelihood of having of developing health conditions as a result of obesity, he added.