It was only a matter of time until the worldwide crises of obesity and immigration law met in the wildest of ways. Immigration officials in New Zealand say that they have told a South African chef he must leave the country. Why? His weight. The man, who weighs 286 pounds, moved to Christchurch six years ago at an even higher weight of 352 pounds. Nevertheless, the country, nearly 30 percent of whose population is overweight, claims he does not represent "an acceptable standard of health." New Zealand may be on its way to violating one of the most important maxims of cooking: never trust a skinny chef.