A private girls' school in west London has been criticised for holding an "Austerity Day" where pupils ate potatoes and fruit for lunch.
St Paul's Girls' School, which has fees of £7,978 per term, said serving pupils "simple" food helps them learn about "less fortunate" people.
Henna Shah, who attended the school on a bursary, said the event made her "uncomfortable".
Campaigners said it showed a "complete lack of understanding" of poverty.
The school, where a typical menu for students includes herb-crusted salmon and duck leg confit, posted about the event on Twitter on Wednesday.
It said said: "Today was the final Austerity Day of the year. Students and staff had baked potatoes with beans and coleslaw for lunch, with fruit for dessert. The money saved will be donated to the school's charities."
Photos accompanying the post included a poster for Austerity Day, showing a waiter lifting a silver cloche with three peas underneath it.
Ms Shah, 24, attended St Paul's from the ages of 11 to 18.
She was the first of her family to go to university when she left the school for Oxford University in 2012.
"Austerity lunch is what we ate at home. It's having to eat a jacket potatoes every day, not having one once a term," she said.
Ms Shah, from Hounslow, said raising awareness for people living in poverty was "great", but that the problem was using the word "austerity".
A spokeswoman for St Paul's told the BBC: "For many years, St Paul's has arranged regular lunches when simple food is served and the money saved given to local charities.
"The aim is also to raise the awareness of our students to those less fortunate than themselves.
"The choice of the word 'austerity' is to draw attention to the fact that others around them are facing significant economic difficulties."
The school refused to explain why the post had been deleted.
'Like Marie Antoinette'
Jack Monroe, a campaigner and author renowned for blogging about cooking for a family on a shoestring budget, told the BBC the stunt was "enormously patronising".
"I'm not outraged, I'm more saddened. They probably feel they are doing something good by playing at being poor," Monroe said.
"An austerity lunch is really no lunch at all.
"I do not know anyone who lives in poverty who can afford to turn their oven on for two hours to cook a jacket potato."
Jane Middleton, a mature student researching food poverty as part of her MA dissertation, said the school's "austerity lunch" was inaccurate.
"People who go to food banks cannot afford fresh food, they get given cans," she said.
"It's shades of Marie Antoinette really - just a complete lack of understanding as to what it means to be in poverty."