But today Li, now 47, is worried that frequent business dinners with colleagues who dine on greasy ribs, fried rice, and beer, has turned into a bigger problem.

Li's mother, a dentist, warned her son that his weight is actually causing his loud snoring, a symptom of sleep apnea - a silent killer that is becoming a growing health problem in China.

"I feel tired in the morning, and family members have been telling me that I sound like I was suffocating when I sleep and snore," Li said.

Li, a furniture factory owner who lives in Chengdu, the capital of southwest China's Sichuan province, has not sought treatment for his snoring problem.

"I've lost some weight, but still snore very loud."

Changing eating habits in China have brought new health problems to the world's most populous nation, as the country's economic boom allowed millions of Chinese to add more meat and processed foods into their diets.

"China has gone from famine to gluttony in one or two generations," said Paul French, a British expatriate living in the country and the author of the book, "Fat China."

When combined with a general lack of participation in organized sports and high rates of smoking and pollution, the increasing availability of high calorie food tips more Chinese into obesity and its related health problems, he said.

Among them are increased rates of obstructive sleep apnea, a disorder in which the throat periodically closes throughout the night, essentially suffocating a person until he or she wakes up, according to sleep doctors.

A fatter Chinese population is leading to more patients with sleep apnea who complain of constant fatigue as a result of deficient deep sleep.

An average of 38.5 percent of Chinese aged 15 or older have a body mass index of 25 or greater, which means they are overweight or obese, according to 2010 figures from the World Health Organization. About 4 percent of the Chinese population is obese, which means they have a body mass index of 30 or greater.

The combined rate of overweight and obese Chinese has increased by 54 percent from 2002, while the rate of obesity alone has increased 208 percent over the same time. About 78 percent of U.S. adults meet the same standard of overweight or obese, according to WHO figures, with 46.2 percent having a body mass index of 30 or greater.

Those who suffer from sleep apnea can be at higher risk for problems ranging from heart attacks to memory loss. Research suggests that effects of untreated sleep apnea are often more serious than insomnia, a condition which many Chinese do not experience due to a cultural tradition of taking afternoon naps, doctors say.

Some Chinese with obstructive sleep apnea are seeking help from medical professionals, according to Dr. Han Fang, the chairman of the Chinese Sleep Research Society whose sleep clinic in Beijing used to have fewer than one patient with sleep-related respiratory problems a week on average, but is now seeing 10-20 of them every night.

These trends may have significant health effects across the world's most populous nation, and may end up benefiting some Western companies such as ResMed (RMD.N) and Amsterdam-based conglomerate Philips (PHG.AS), analysts said.

Both companies make devices that help patients breathe easier during sleep.

INCREASING OBESITY IN CHINA

Numerous studies have suggested that Asians are already more likely to have the disorder than Caucasians because of facial structures that result in smaller upper airways. One 2011 study published in the journal Sleep and Breathing found that nearly 70 percent of Asian subjects had some form of sleep apnea. Fatty tissue in the throat brought on by weight gain can bring on or exacerbate the condition, doctors say.

Doctors said that high-calorie, Western-style fast food is a leading factor in China's increasing sleep issues. As consumer preferences have shifted away from full-service restaurants, China's $90 billion fast food industry has expanded at an annualized rate of 16.9 percent over the last five years, according to Los Angeles-based research firm IBIS World. There are now over 1.9 million fast food restaurants in the country.

"The increase of sleep problems is definitely related to the increase of obesity in China, which partially results from changes of the diet structure of Chinese people," Dr. Han told Reuters in a phone interview.

High-calorie fast-food especially contributes to rising rates of sleep apnea in children, who are more likely to eat foreign fast food than older generations, he said.

Indeed, rising consumer incomes and changing tastes have driven the expansion of Yum Brands' (YUM.N) KFC, Pizza Hut and other Western-style fast food restaurants such as McDonald's (MCD.N) in urban areas over the last decade.

Dr. He Quanying, the head of the sleep research branch of the Chinese Medical Association, said that "with an increasing obesity rate in China, we will definitely see more sleep problems like apnea." He said that the blame for the rising apnea rates comes down to the fact that "Chinese are eating too much and don't exercise enough."

ACCESS TO TREATMENT

Some of the increased demand for sleep apnea treatments can be traced to greater awareness of the problem and access to treatment. Doctors note that the increasing number of obese have led to corresponding higher cases of sleep apnea.

Millions of Chinese with sleep apnea may not recognize that they have the disorder, doctors said, which makes accurate incidence reports hard to come by. Studies generally show that at least five percent of the population in industrialized countries have some form of sleep apnea, according to Dr. David Rapoport, the director of New York University's Sleep Disorders Center.

In China, that translates into at least 70 million cases, he said. Nearly 20 percent of the U.S. population may have at least a mild form of sleep apnea as a result of obesity, he noted. The true extent of the problem in China may not be known because relatively few doctors or patients are familiar with the disorder, Rapoport said.

"We're barely scraping the surface" in terms of medical attention, he said.

That may change as broad income gains allow Chinese to both consume more food and have more money to spend on healthcare.

China's health spending is projected to increase by 10.3 percent per year through 2020, according to an estimate from AllianceBernstein, the largest among the 15 countries with the highest expected healthcare spending over the same time. Spending in the U.S., by comparison, is expected to rise by 4.6 percent per year.

Increased spending and sophistication on the part of Chinese patients should also lead to higher spending on sleep apnea treatments as well.

Peter Farrell, the chief executive of San Diego-based ResMed, recently told analysts that the market for his company's sleep aid products in China and India should increase by more than 10 percent a year because it is building from a small base. But the overall market has not "reach the point where it is hugely material for us just yet," he said.

ResMed is one of the leading makers of continuous positive airway pressure, or CPAP, machines that use air pressure to prevent a patient's throat from closing. Philips, whose Respironics division is the other leading CPAP-maker, did not respond to a request seeking comment for this story.

China's obesity rates will be a long-term driver for sales growth for ResMed and Respironics, the two leading companies in the CPAP market, said Ben Haynor, an analyst at Feltl and Company, an investment firm in Minneapolis.

"(Doctors) are becoming aware of the hand-in-hand nature of obesity and sleep apnea. This is going to be a tremendous opportunity," he said.

(Reporting By David Randall and Hui Li in Beijing; Editing by Walden Siew and Bernard Orr)

(David K. Randall is the author of "Dreamland: Adventures in the Strange Science of Sleep," published by W.W. Norton.)

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