Anais Martinez is on the hunt in Mexico City's Merced Market, a sprawling covered bazaar brimming with delicacies. "So this is the deep-fried tamale!" she says with delight, as if she'd just found a fine mushroom specimen deep in a forest.

The prized tamales are wrapped in corn husks and piled next to a bubbling cauldron of oil.

"It's just like a corn dough patty mixed with lard, put in a corn husk or banana leaf, steamed and then deep fried," says Martinez of this traditional Mexican breakfast. "And then after you fry it, you can put it inside a bun and make a torta [sandwich] out of it. So it's just like carbs and carbs and fat and fat. But it's actually really good."

And it only costs 10 pesos — roughly 50 cents.

Martinez is a designer in Mexico City. She studied gastronomy here and now moonlights for a company called Eat Mexico giving street food tours.

Deeper in the market there's an area packed with taco stalls. Customers stand at the counters or sit on wobbly plastic stools. The young cooks fry, flip and chop various meats into tortillas. They pound strips of flank steak out on wooden cutting boards. Piles of red chorizo sausage simmer in shallow pools of oil. Yellow slabs of tripe hang from meat hooks.

We've just come to one of Martinez's favorite taco stands. Its specialty is pork tacos served with french fried potatoes piled on top.

"The pork is really thinly sliced, rubbed with chiles and spices and then they fry it," Martinez says as the meat sizzles on a long steel griddle in front of her. "Also, really good."

Rich, fatty street food like this is available all over Mexico — at bus stops, at schools and on street corners. And it's affordable to the masses. A heaping plate of Martinez's favorite pork tacos costs less than a dollar.

All that cheap food — in a country where incomes are rising — is contributing to Mexico's massive diabetes epidemic.

Diabetes is now the leading cause of death in Mexico according to the World Health Organization. The disease takes an estimated 80,000 lives each year. Nearly 14 percent of adults in this country of 120 million suffer from the disease — one of the highest rates of diabetes in the world. And it's all happened over the last few decades.

For roughly $2 a day, people in Mexico can now afford a diet heavy in carbohydrates, sugar and fat that delivers way more calories than the WHO's recommended daily intake of 2,000. A study in 2015 showed Mexico to be the leading consumer of junk food in Latin America, consuming 450 pounds of ultraprocessed foods and sugary beverages per person each year.

Until just recently Mexico was the largest per capita consumer of soda in the world, chugging down 36 gallons of sugary drinks per person per year. That dubious distinction now falls to Argentina, with the U.S. and Chile not far behind.

Excessive body fat is one of the main contributors to the onset of Type 2 diabetes. And obesity rates have been climbing steadily in Mexico. It's now one of the world's most overweight countries, coming in just behind the United States.

Mexican health officials are well aware of the crisis. Late last year, the health minister declared diabetes and obesity to be public health emergencies — the first time they'd made such a declaration that wasn't targeting an infectious disease.

"Diabetes is one of the biggest problems in the health system in Mexico," says Dr. Carlos Aguilar Salinas at the National Institute of Medical Sciences and Nutrition in Mexico City. "It's the first cause of death. It's the first cause of disability. It's the main cost for the health system."

Treating a patient with a severe case of diabetes in Mexico, he says, can cost upward of $40,000 a year. But the bigger problem, Aguilar says, is that the Mexican health system isn't prepared to treat the sheer number of diabetes patients with serious medical complications who show up in its clinics every day.

"The Mexican health system is very efficient to treat infectious disease," he says. But chronic disorders like diabetes, which require lifelong attention and medical monitoring, call for a different skill set from doctors. And Mexico's health system is still adjusting to this shift toward treating chronic disease.

Recognizing how daunting it is to treat diabetes, Mexican officials are trying to prevent it in the next generation. In 2014 the country slapped a controversial 5 cents per liter tax on soda. New rules bar advertisements for high calorie junk food aimed at children. Public service announcements encourage people to exercise more. And there's a major push to restrict the sale of soda and junk food in schools.

The head of the World Health Organization's office in Mexico, Dr. Gerry Eijkemans, says diabetes is a huge challenge to health care systems throughout Latin America.

"Diabetes used to be a disease of the rich," she says. "In Western Europe and the U.S., it was really the people who had the money who were obese, and now it's actually the opposite."

This is forcing already overstretched public health systems in Latin America to devote more resources to this complex disease.

"In order to prevent an infectious disease, you reduce the mosquitoes and basically you're done," Eijkemans says. "Not that it's easy, but it's much easier than changing a lifestyle, changing the way a society is basically organized [to encourage] people to consume unhealthy food with lots of fat and sugar."

An article earlier this year in the medical journal The Lancet warned: "Rising levels of increasingly severe obesity mean that, worldwide, populations are on the brink of a catastrophic epidemic of diabetes."

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