The singer, who shed oodles of weight to gain the size eight figure, is on a healthy diet pattern that includes herbal tea for breakfast, sushi for lunch and raw vegetable crudites with dried fruit for dinner.
The Smile singer, who once called herself 'fatter and uglier than Amy Winehouse', orders lunch from Michelin-starred Nobu in Mayfair.
Her everyday cart off includes Posh Spice's favourite food -edamame, or baby soya beans.
A source close to the 22-year-old said that Allen thinks sushi is a great way to maintain body without starving.
"Lily is crazy about sushi and says it's a great way to feel full without piling on the calories,' the Daily Mail quoted the source, as saying.
"She looks forward to her lunch because breakfast is a bit non-existent and dinner is rather dull," the friend added.