In Japan, being thin isn’t just the price you pay for fashion or social acceptance. It’s the law.So before the fat police could throw her in pudgy purgatory, Miki Yabe, 39, a manager at a major transportation corporation, went on a crash diet. In the week before her company’s annual health check-up, Yabe ate 21 consecutive meals of vegetable soup and hit the gym for 30 minutes a day of running and swimming.”It’s scary,” said Yabe, who is 160 centimetres tall and weighs 60 kilograms. ”I gained two kilos this year.”In Japan, already the slimmest industrialised nation, people are fighting fat to ward off dreaded metabolic syndrome and comply with a government-imposed waistline standard.Metabolic syndrome, known here simply as ”metabo”, is a combination of health risks, including stomach flab, high blood pressure and high cholesterol, that can lead to cardiovascular disease and diabetes.Concerned about rising rates of both in a greying nation, Japanese legislators last year set a maximum waistline size for anyone age 40 and older: 85 centimetres for men and 90 centimetres for women.The experience of the Japanese offers lessons in how complicated it is to legislate good health.Though Japan’s ”metabo law” aims to save money by heading off health risks related to obesity, there is no consensus that it will.Doctors and health experts have said the waistline limits conflict with the International Diabetes Federation’s recommended guidelines for Japan. Meanwhile, ordinary residents have been buying fitness equipment, joining gyms and popping herbal pills in an effort to lose weight, even though some doctors warn they are already too thin to begin with.The number of ”food calories which the Japanese intake is decreasing from 10 years ago”, said Yoichi Ogushi, professor of medicine at Tokai University and one of the leading critics of the law. ”So there is no obesity problem as in the USA. To the contrary, there is a problem of leanness in young females.”Under Japan’s healthcare coverage, companies administer check-ups to employees once a year. Those who fail to meet the waistline requirement must undergo counselling.If companies do not reduce the number of overweight employees by 10 per cent by 2012 and 25 per cent by 2015, they could be required to pay more money into a healthcare program for the elderly. An estimated 56 million Japanese will have their waists measured this year.Healthcare costs in Japan are projected to double by 2020 and represent 11.5 per cent of gross domestic product. That’s why some health experts support the metabo law.Though the health exams for metabolic syndrome factor in blood pressure, cholesterol, blood sugar, weight and smoking, waist size is the most critical element in the law – and perhaps the most humiliating.On the day of her exam, Yabe arrived at the clinic at 8.30am. The tests lasted an hour. The result: her waist was 84 centimetres – safely under the limit. She had shed 2.95 kilograms thanks to her diet and exercise.A week later, however, Yabe was back to eating pasta and other favourite foods. ”I want to keep healthy now, but I don’t know,” she said. ”Maybe in December I will have many bonenkai [year-end parties]. And next summer I will drink beer, almost every day.”