"The food was shared out around the staff and everyone could get involved if they wanted. Adele had some jerk chicken and a salad with mango.
"It was clear that everyone was on such a high once the filming stopped. The atmosphere was buzzing and a free dinner for some of the crew felt like a real treat."
Adele, 32, has transformed her lifestyle over recent months and she opted for the healthy options on her rider.
The source told The Sun newspaper: "For Adele they had put out matcha green tea powder and an electric kettle so she could make as many brews as she wanted.
"There was also dark chocolate with almonds from Whole Foods and a couple of decent bottles of wine."
During her on-screen appearance, Adele poked fun at her impressive weight loss.
Addressing her slender figure in her opening monologue, the 'Hello' hitmaker said: "I know I look really really different since you last saw me. But actually because of all the COVID restrictions and the travel bans, I had to travel light and I could only bring half of me, and this is the half I chose."
The London-born singer also spoke about her history with 'Saturday Night Live', after she first appeared as the musical guest 12 years ago.
She said: "I'm absolutely thrilled to be finally hosting this show. A show that not only do I genuinely love, but the show that broke my career here in America, 12 very long years ago.
"I was the musical guest back in 2008, when Sarah Palin came on with Ms. Tina Fey, and so obviously a few million people tuned in to watch it and the rest is now history."