Mexico probably will surpass the US in obesity rates for the first time next year as it adopts the fast food and sedentary lifestyles of its neighbour, according to the Bloomberg news agency.

The health crisis prompted Mexico's congress this month to move toward making school exercise mandatory. Mexico City has called in a Texas doctor to wean kids off pizza and fries, while Health Ministry ads warn fat can lead to diabetes and heart disease.

"Obese and overweight adults went from nowhere in 1990 to 62% in 2000," said Barry Popkin, an economist and nutrition professor at the University of North Carolina-Chapel Hill, citing a Mexican government study. "You are talking about an astronomical increase coming at a very fast rate and it's continuing."

Weight-related illnesses pose a growing threat to Latin America's second-largest economy, said Juan Rivera, who's leading Mexico's second national obesity study at the National Institute of Public Health, due in 2006. Diabetes alone, the most common disease associated with excess weight, cost Mexico as much as US$15.1bn in 2000, mostly in reduced productivity and lost wages because of premature death, according to a World Health Organization estimate.

A report this year by the Paris-based Organization for Economic Co-operation and Development compared obesity rates among OECD member nations. Only the US, where 66% of people are overweight or obese, ranks higher than Mexico, the group reported, using the 2000 data from Mexico and 2002 numbers from the US.

"The causes of death in Mexico have changed from infectious to chronic diseases such as cardiovascular illnesses and diabetes," said Jose Angel Cordova Villalobos, president of the Heath Committee of Mexico's Congress. "In most cases these diseases share the common cause of obesity."

Incomes in Mexico have grown as the economy expands. Gross domestic product rose 3.3 percent in the third quarter from the same period a year ago. Average salaries, in inflation-adjusted terms, have climbed to MXN188.74 (US$17.80) per day from MXN146.19 per day four years ago.

Mexicans' growing weight is largely a byproduct of rising consumer spending aided by US free trade, said Rivera, a nutritionist. A North American lifestyle that features cars and television accounts for much of that, he said. At the same time, the spread of fast food and soft-drink consumption in place of traditional beans and tortillas has paralleled the typical waistline expansion, he said.

The first Mexican franchise of Oak Brook, Illinois-based McDonald's Corp. opened in 1985 and there are now 304 outlets, according to the company's Web site. Miami-based Burger King's first restaurant opened in 1991 and has 260 sites. Louisville, Kentucky-based Yum! Brands, Inc, which operates Taco Bell, Pizza Hut and KFC franchises, had 467 restaurants in Mexico at the end of 2004, according to a company report.

Fast-food restaurants in the US deny their products directly cause obesity or health problems.

A government study of income and spending showed Mexicans, whose traditional diet is based on corn and beans, spent 29.3% less on fruits and vegetables in 1998 than in 1984. In the same period, soft drink purchases increased 37.2%.

Researchers conducting the nation's second study on obesity, due to be published next year, said the percentage of obese and overweight Mexicans probably rose as high as 85% of women and 75% of men --possibly the highest rates of any major economy.

The sole national study in Mexico that tracked weight gain over time looked at only women between the ages of 18 and 49. It found 59.6% were overweight or obese in 1999 compared with 33.4% in 1988.

In addition to eating more calories and fat, the average Mexican is exercising less, said Lupe Aguilar, head of physical education for the capital's schools. Children and adults have cut back on walking and other outdoor activities, a trend reinforced by the rising crime rate, she said.

"We can't expect a parent to tell their children to go play in a park," Aguilar said. "
We are now worried that physical activity is only happening in the school."

Aguilar is implementing a new exercise and education program in the city. The regimen, approved this month by the lower house of congress and sent to the senate, would require that students exercise before classes.

Schools in Mexico City already asked San Antonio physician Robert Trevio for help getting students to slim down. Trevino started a bi-lingual program used in more than 200 South Texas elementary schools that combines nutrition education with exercise requirements.

Schools in the program stopped serving sweetened beverages at lunch and offer French fries and nachos only once a week, Trevino said.

"It wasn't easy," he said. "The food services are profit centres, they have to make money."