The coach of China's women's volleyball team has blamed three weeks of vegetarianism for his side's poor performance in the FIVB World Grand Prix finals, culminating in a 3-0 drubbing by the US in Ningbo , Zhejiang province, on Sunday night. Yu Juemin said that to avoid accidentally consuming banned substances, his athletes had given up meat for three weeks, leading to significant physical declines. China suffered four consecutive defeats in the finals, and ended up ranked fifth among the six teams competing, behind the United States, Brazil, Turkey and Thailand. 'We dare not eat meat when competing outside because of fears over clenbuterol,' Yu said. 'Now we are in the critical moment for the London Olympics, which allows no room for any carelessness.' Since early last month, China's women's volleyball team has competed in the world grand prix series in Macau, Foshan and Luohe . They did not consume any meat until the finals in Ningbo, where they were served meat at the national volleyball training centre in the city. More than one Chinese athlete suffered cramps during the Ningbo finals, The Beijing News reported. Chinese athletes preparing for the London Olympics have been avoiding meat because of concerns that it might contain substances such as clenbuterol, which is banned by the World Anti-Doping Agency and by mainland food authorities but has been found in some mainland pork. Tong Wen, a 2008 Olympic women's judo gold medalist, was stripped of her title and banned for two years after testing positive for clenbuterol in 2010, prompting the authorities to more strictly supervise athletes' diets. Early this year, the General Administration of Sports issued an urgent order about the safety of meat, banning athletes from eating pork, beef or lamb when dining out. It has been widely reported that the Chinese marathon team has been raising chickens at its training centre in Yunnan , while a judo team in Tianjin has raised 20 pigs - all seen as efforts to avoid domestic meat products. However, the Ministry of Agriculture recently said that 99.94 per cent of meat tested was free of clenbuterol, the highest rate in history. Following Yu's comments, microbloggers have been worrying that food safety problems could torpedo China's Olympic dreams. 'China's dream of being a sporting superpower is so powerless when faced with the food safety problem,' one microblogger wrote. Another said: 'Maybe the national sport teams should take the pigs they raise with them next time.'