The Prime Minister announced her intention to abstain from the savoury potato snack for the 40 days before Easter, during a reception in Downing Street.
Joined at the event by prominent figures including the outgoing Bishop of London, Tim Hughes, Cardinal Vincent Nichols and Nicky Gumble, Mrs May also paid tribute to the contribution believers make to society.
In a speech, she said: "Growing up in a vicarage, I know first-hand the many sacrifices involved and the hard work that so many of you do, from the services and ministry in your churches to the comfort and guidance you provide to millions in our country at some of the most difficult moments in their lives."
Holding an annual reception for each of the UK's major faith groups, Theresa May said her gathering with Christians held "particular importance" for her, as a believer herself.
The PM also used the event to praise the service of retiring Bishop of London Rt Rev Richard Chartres and highlight the plight of persecution against Christians.
She went on to say: "Now, the Church will not always agree with everything that the government says - and the government will not always agree with the Church.
"But I think there are many areas where we can work together. One is in addressing the persecution of Christians and religious minorities around the world which has been mentioned to me by some at the reception here today.
"It is hard to comprehend that today people are still being attacked and murdered because of their Christianity.
"We must reaffirm our determination to stand up for the freedom of people of all religions to practice their beliefs in peace and safety. And I hope to take further measures as a government to support this."