There are many reasons why the world is ensnared in an obesity epidemic, and they don’t only involve the quantity of food people are eating (though that’s a big part of it). In some cases, toxic substances found in products we encounter everyday are contributing to the problem–along with genetically modified food , forks , and countless other factors. Today’s obesity epidemic has also led to a diabetes epidemic–today, 25.8 million people in the U.S. (that’s more than 8% of the population) have diabetes.

In a study published recently in the journal Pediatrics, researchers from New York University School of Medicine found a strong link between insulin resistance in U.S. teens and their urinary concentration of DEHP, a chemical (specifically a type of phthalate) used in medical equipment and packaged food. Researchers have previously seen links between insulin resistance–a precursor to diabetes that can trigger weight gain–and DEHP levels in both adults and animals.

When the body becomes insulin resistant, it’s akin to having rusty keys that won’t turn.

Using a national survey, the researchers collected data from a sample of teenagers related to glucose levels, fasting insulin, height, weight, poverty, ethnicity, and other factors. Phthalate levels were measured using a urine sample.

Their results: Higher phthalate levels were linked to insulin resistance. The researchers write that more studies are needed:

While dietary sources are likely to be the chief source of exposure, given the uses of DEHP in other products, we cannot rule out nondietary sources as contributors to the associations identified here…Knowledge gaps also persist in understanding food contamination with DEHP. A comprehensive review suggests that most studies are dated and may not represent current exposures.

Insulin resistance is, according to diabetes educator Gary Scheiner, “the root cause of almost all cases of Type 2 diabetes.” Insulin (a hormone generated in the pancreas) regulates the amount of sugar in the bloodstream by directing glucose into fat, muscle, and liver cells. It’s like a key that unlocks access to these cells, Scheiner explained to the Chicago Tribune. When the body becomes insulin resistant, it’s akin to having rusty keys that won’t turn–glucose can’t get into cells, and the body panics at the rise of blood sugar in the pancreas, producing even more insulin. Blood sugar eventually rises to untenable levels, and diabetes occurs.

In a study earlier this year, Dr. Leonardo Trasande–the lead author on the DEHP paper–also found that low-molecular weight phthalates, often found in cosmetics, lotion, and creams, are linked to increased body mass among African American children. Phthalate exposure, the report explained, could be responsible for a 1.7 pound increase in body weight in children.

There are ways to avoid phthalate exposure in daily life. Don’t use unnecessary personal care products, for starters. And the researchers suggest that it’s possible to avoid some DEHP exposure by opting for fresh foods instead of foods that are canned or wrapped in plastic–a move that can reduce DEHP metabolites up to 56%. Certain kinds of packaging, like wax paper and aluminum wrap, don’t contain DEHP at all.