Obesogens are chemicals that are believed to mimic and interrupt regular hormone function. Researchers say these chemicals can cause weight gain and lead to other major health problems like heart disease, diabetes or endocrine and metabolic disorders.

Obesogens can be found in food packaging, plastics, pesticides and chemicals, as well as some cosmetics. They include PCBs, BPA and pthalates. They can alter genes and pose as hormones that help regulate the body’s metabolism. Take estrogen, for example.

Estrogen, the “female hormone,” typically causes women to gain weight during menopause. When obesogens enter the body, they act like estrogen, reprogramming cells to become fat cells. The body will work to convert calories into fat cells, which produce more estrogen. If what researchers say about obesogens is true, diet and exercise may not be enough to lose weight.

Professor Bruce Blumberg, a biologist from the University of California-Irvine who coined the term, says the causes of obesity are complex, but that the problem is more prevalent in America. He has an idea why: “Elsewhere, the consumption of prepackaged foods is much lower,” he explained in a UCI press release. “Food is grown and eaten locally, and people are far less exposed to food additives and chemicals. These are all contributing factors.”

Obesogen research is a fairly new thing. It’s in its early stages now, but as more scientists accept the idea, more is discovered about the effects these chemicals play in interrupting endocrine function.

Until then, Blumberg suggests ditching the Tupperware. “Use glass and stainless steel instead of plastics to store fluids and foods,” he says, “and try to get locally grown produce, organic if possible.”