Various studies conducted using animal models have shown that the chemicals, known as endocrine disrupters, mimic natural hormones that helps in regulating how many fat cells a body makes and how much fat to store in them.
Scientists argue that diet and too little exercise may not be the key reasons for rise in obesity.
Food intake and exercise just haven't changed that much in that period. And while genetics obviously play a role - just think of someone you know who can eat three Big Macs a day and never gain an ounce - these researchers say it would be impossible to see such widespread genetic change in just two decades, giving them more reason to suspect the environment.
A recent data from US Centres for Disease Control and Prevention has revealed that about 93 percent of the US population had bisphenol A, a chemical found in canned goods and in hard, clear plastic items such as baby bottles and hiking containers, in their body.
Jerry Heindel, a program administrator for the National Institute of Environmental Health Sciences also believe that chemicals play an important role in obesity
"This is a really new area . . . but from multiple labs on multiple levels we are getting preliminary data that all say the same thing: Chemicals can play a role," Environmental News Network quoted Heindel, as saying.
"We know that nutrition and exercise are very, very important, but underlying that could be environmental exposures during development that alter your physiology, including how you respond to food and exercise," he added.
According to the researchers studying obesity, endocrine disrupters have already been linked to reproductive problems in animals and humans and are known to affect fat cells.
Bruce Blumberg of the University of California, Irvine, has even already given these chemicals a new name 'Obesogens'.
Another study at the University of Missouri-Columbia showed that mice fed with lower amounts of bisphenol A during early development become more obese as adults than those that weren't fed the chemical.
Tufts University scientists observed similar phenomenon in rats.