By Julie Mazziotta, People
March 08, 2017
Mike Marsland/WireImage

This article originally appeared on

Ever since Adele came out with her Grammy Award-winning 25, she’s been on a major health kick. The singer says she ditched cigarettes and now works out regularly with her trainer, who puts all of his clients (which, in addition to Adele, include Pippa Middleton and Kim Cattrall) on The Sirtfood Diet.

The diet book, which launches in the U.S. March 7, focuses on Sirtfoods — a “newly discovered group of wonderfoods” that are in common, everyday items like kale, cocoa, strawberries, coffee and more.

“Sirtfoods are a newly discovered group of wonder foods that contain special plant nutrients known as polyphenols that activate a powerful recycling process in the body which clears out cellular waste and burns fat,” the program’s creators, Aidan Goggins and Glen Matten, explain. “They do this by activating our sirtuin genes — also known as our ‘skinny’ genes. Indeed, these are the very same genes that are activated by fasting and exercise.”

Goggins and Matten searched for foods with the highest levels of polyphenols to formulate a diet plan that Adele’s trainer, Pete Geracimo, says “isn’t really a diet.”

“Whenever I talk nutrition with my clients, if they’re trying to lose weight, I always tell them to look at these Sirtfoods,” he told PEOPLE. “You lose weight without losing muscle. It takes it to the next level.”

The program is split into two phases that each last seven days. Dieters start phase one by replacing breakfast and lunch with three green juices, with meals like Asian shrimp stir-fry with buckwheat noodles or miso and sesame-glazed tofu with ginger and chili stir-fried greens for dinner. By day four, users are up to two full meals a day, and by phase two, their eating Sirtfood-rich meals at regular intervals.

Goggins and Matten found in trials that dieters lost an average of 7 lbs. in seven days — and one PEOPLE reporter is going to put that challenge to the test over the next week. Stay tuned!