Mexico City - With each bite into a greasy taco and slurp of a sugary drink, Mexico hurtles toward what health experts predict will be a public health crisis from diabetes-related disease.

A fifth of all Mexican women and more than a quarter of men are believed to be at risk for diabetes now. It's already the nation's No. 1 killer, taking some 70,000 lives a year, far more than gangster violence.

Public health experts blame changes in lifestyle that have made Mexicans more obese than anywhere else on Earth except the United States. They attribute changes to powerful snack and soft drink industries, newly sedentary ways of living and a genetic heritage susceptible to diabetes, a chronic, life-threatening illness.

The results are evident at public hospitals, where those needing treatment for diabetes-related illness, such as blindness and kidney dialysis, clamor for help.

"The first time we came, we had to wait 12 days for my husband to get dialysis," said Marta Remigio Jasso, who spoke on the grounds of the General Hospital of Mexico, a public unit of the Secretariat of Health. "I slept under my husband's hospital bed."

Already, some 150,000 Mexicans receive kidney dialysis, but nearly the same number are denied treatment for lack of insurance, said Dr. Abelardo Avila Curiel, a physician and expert in population studies at one of Mexico's most prestigious medical centers, the Salvador Zubiran National Institute of Medical Sciences and Nutrition.

"When we project the increase in diabetes and the costs associated with it, the Mexican health system will be overwhelmed. It can't be paid for. By the year 2020, it will be catastrophic. By 2030, it faces collapse," Avila said.

Somewhere between 6.5 million and 10 million Mexicans now have diabetes, the Health Secretariat says. While the numbers are fewer than the 20 million who suffer from diabetes in the United States, Mexico carries the seeds of an unfolding tragedy linked both to soaring obesity and shifting demographics that will heavily burden health systems.

"In the next four decades, the population of people 65 years and older will quadruple," said Manuel Ordorica Mellado, a demographer at the Colegio de Mexico, a public research and teaching institution. "This is vertiginous growth."

By the middle of the century, Mexico is likely to have 25 million elderly people, he said, equivalent to the nation's entire population as recently as 1950.

The elderly are among those suffering the worst from diabetes-related illness.

"Diabetes is the primary cause of blindness in Mexico. It's also the main reason for amputations," said Carmen Reyes de Ortega, the executive director of the Mexican Diabetes Association, a nonprofit advocacy and educational group.

"The panorama is not good," Reyes de Ortega continued. "We'll have a lot of people suffering blindness, with mobility problems and needing dialysis."

The once-languid pace of Mexican life has undergone radical transformation in recent decades. Crowded urban areas force long commutes on workers, and public security concerns keep them cooped up at home.

Workers who once would return to their homes for long lunch breaks, eating freshly prepared foods, no longer can do that.

"It is practically impossible to go home to eat lunch now," said Dr. Gabriela Ortiz, a department director at the National Center for Preventative Health and Disease Control. "We ask for food to be delivered to our office. Some employees go out to the taco stands on the corner or to the street markets."

Since tap water is widely considered unsafe, and public drinking fountains rare, most Mexicans swill a sugary drink with their meals. The average Mexican consumes 728 8-ounce sugary drinks from Coca-Cola per year, an average of two a day, far more than the 403 eight-ounce drinks that are consumed per person annually in the United States.

"Coca-Cola is a great villain, but it is not the only one," Avila said, adding that some 30 of Mexico's 500 largest businesses produce snacks or other types of junk food, carbonated or sugary beverages. He said their total annual sales top $80 billion and their advertising and lobbying budgets easily trump public health campaigns.

A 2012 federal health and nutrition survey found that 64 percent of men and 82 percent of women in Mexico were overweight or obese. Obesity levels have tripled in the past three decades.

"I'm looking out my window," said Dr. Stan De Loach, an American-certified diabetes educator who has lived most his life in Mexico, "and I see two, three, four, seven, eight people out of maybe 20 people who are obese."

Mexico now has higher obesity rates among children ages 5 to 11 years than any other country. According to a 2012 health survey, 34.4 percent of children are obese, Ortiz said. The comparable figure in the United States is 16.9 percent, according to the National Center for Health Statistics.

"Diabetes 10 years ago was a problem mainly among people 55 years and older. But now we see cases even in young people 12 and 13 years old," said Reyes de Ortega of the Mexican Diabetes Association.

In Mexico, some 400,000 youth suffer from diabetes Type 1 (which requires insulin injections) or Type 2 (which is associated with obesity, inactivity and family history).

Amid worries about rising childhood obesity, lawmakers in 2010 limited the kinds and quantities of food and drinks that could be offered at public schools. But vendors still congregate outside school gates at the end of each day to peddle fried snacks, sweets and sodas.

"Why do they keep selling potato chips and ice cream at the school where my son goes?" asked Fabiola Balbuena Torres, a 31-year-old professional wrestler who goes by the ring name Faby Apache. Torres is one of scores of pro wrestlers taking part in "Fight Against Obesity," a program to encourage youngsters to consume healthy foods.

Many of the alarm bells sounding about diabetes and its long-term impact come from experts outside government.

"It's a bomb. It's an extremely urgent problem," Reyes de Ortega said.

Health Secretariat officials say the government will do what it can to treat diabetes-related illnesses, acknowledging that kidney dialysis eats up as much as half of the budget earmarked for diabetes.

But pledges of universal health coverage do not match reality.

"The health system in Mexico operates with smoke and mirrors," said Dr. Joel Rodriguez, a nephrologist. "If you have social security, they give you an appointment in eight months or a year. You end up going to a private clinic because you can't get in to see the doctor."