Leith sold her businesses, the Michelin-starred restaurant Leith's Good Food as well as Leith's School of Food and Wine in 1995. She is a consultant to catering group Compass, which is involved in supplying school meals.
This term has already seen the introduction of healthy menus for school canteens. Tougher nutrient standards are expected to follow.
Salty, sugary and fatty snacks are also being removed from school vending machines, although full rules on their contents don't take effect until next September.