On an obese continent in an obese world, young Mexicans stand out as more susceptible than average to the condition and its plethora of comorbid health ailments.

More than one-third of young adults in Mexico may be genetically predisposed to obesity, says a researcher at the University of Illinois who just completed a study there. After visiting the Universidad Autónoma de San Luis Potosί, Margarita Teran-Garcia, a professor of food science and human nutrition, described her study of young adults, mostly college students aged 18- to 25-years-old.

"The students who inherited genetic risk factors from both parents were already 15.5 pounds heavier and 2 inches bigger around the waist than those who hadn't," she said. "They also had slightly higher fasting glucose levels."

In the study, investigators tested 251 young Mexicans for alleles associated with risk on the FTO gene, collaboration between the U.S. and Mexican institutions called "Up Amigos." They followed 10,000 students there to observe changes in weight, body mass index (BMI), and behavior affecting health changed over time.

The gene studied is associated with a predilection for obesity, increased BMI, and increased waist size, traits that indicate many health problems including diabetes and heart disease. Of those tested, 15 percent had inherited the gene from both parents, thus carrying two copies of the marker allele.

"If young people realize early that they have this predisposition, they can fight against it, Teran-Garcia said. "If they are at risk for obesity, eating a healthy diet and getting regular exercise is even more important for them."

In the United States, 85 percent of Hispanics are of Mexican derivation. However, few studies had examined the impact of this particular gene on people of Mexican heritage, on either side of the Southern border — with FTO-related information available for whites, Asians, and African Americans.

"This is the first study to target young adults in Mexico, although one other study has followed older Mexican adults who had already been diagnosed with diabetes, obesity, and obesity-related diseases," she said.

Like many other parts of one's genome, FTO and other so-called "fat" genes may be influenced by epigenetic modifications, with changes in behavior possibly affecting one's children well into the future.

"So even if you have this predisposition, you may be able to change the way those genes behave by eating the right foods and getting more exercise," Teran-Garcia, said. "These good habits are especially important for young people who have a genetic risk for obesity."

The study was published Wednesday and is available online in the Open Journal of Genetics.

Source: Garcia, T, Vazquez-Vidal, I, Mosley, M, et al. FTO genotype is associated with body mass index and waist circumference in Mexican young adults. Open Journal of Genetics. 2013.