Obesity rates have jumped in the recent years. Unhealthy lifestyle habits like eating high calorie food, and lack of physical activity, have been cited as reasons behind this massive increase in the rate of obesity. Three new studies show that sugary drinks are associated with higher weight gain.

"I know of no other category of food whose elimination can produce weight loss in such a short period of time. The most effective single target for an intervention aimed at reducing obesity is sugary beverages," said Dr. David Ludwig from Boston Children's Hospital to Reuters Health. Ludwig was involved in one of the studies on obesity and sugary drinks.

Since the 1970s, the consumption of sugary drinks and obesity rates in the U.S. has doubled. One study found an association between sugary drinks and genetic pre-disposition to weight gain.

Researchers assessed the obesity and genetic link in more than 33,000 men and women who were participating in long-term health studies.

They found that people who consumed large amounts of sugary drinks were two times more likely to gain weight due to genetic factors than people who did not, meaning that while people might be genetically vulnerable to weight gain, sugary drinks accelerated the effects.

Lu Qi from the Harvard University said that the study findings support legislation designed to reduce sugary drink intake, like New York City's recent ban on sodas larger than 16 ounces.

In another study led by Dr. Ludwig, researchers found that non-caloric drinks could reduce weight in obese children. In this study, 224 children were randomly assigned to either drink non-caloric beverages or sugary drinks. The study showed that availability of healthy foods could reduce obesity rates in children.

In the third study, 641 children from a school in Denmark were randomly assigned to either get a can of sugary drink or a non-caloric drink for one and a half year. The drinks were similar in appearance and taste. Researchers found that children who drank the "masked beverage" gained less weight after a year than kids who drank regular sugary drink.

The studies are published in The New England Journal of Medicine.