LOVERS of Mexican food take note: a single dinner at a Mexican restaurant can contain more salt, fat and saturated fat than one person should consume in an entire day, according to a US study reported in New Scientist. Laboratory analysis of 15 Mexican dishes by The Center for Science in the Public Interest found that only one - chicken fajitas with flour tortillas - met US government guidelines that no more than 30 per cent of calories should come from fat. The worst offender was chillies rellenos, which is like eating 'a stick of butter and one-and-a- half teaspoons of salt'.