Oprah Winfrey has challenged herself to eat a vegan diet for 21 days.

The US chatshow host agreed to take part in a '21 Day Cleanse' after speaking to Kathy Freeston about her book Quantum Wellness.

Winfrey said that she could associate with Freeston's assertions that you can only reach a "spiritual integrity" when you acknowledge "the animals whose lives are sacrificed in the name of gluttony".

Writing on her official blog about her first day on the diet, Winfrey said: "Wow, wow, wow! I never imagined meatless meals could be so satisfying.

"I had been focused on what I had to give up - sugar, gluten, alcohol, meat, chicken, fish, eggs, cheese. 'What's left?' I thought. Apparently a lot.

"I can honestly say every meal was a surprise and a delight, beginning with breakfast - strawberry rhubarb wheat-free crepes."