Geri Halliwell "is finally comfortable in her own skin".
The Spice Girls star - also known as Ginger Spice - has gone through a public battle with bulimia and in the past has thanked former Take That member Robbie Williams for helping her overcome the disorder.
The 'Look at Me' singer, who wore a Suzanne Neville design at the 2012 London Olympics Closing Ceremony concert is a big exercise fan and used her favourite activities to help her get in shape for the gig.
A source told Us Weekly magazine: "Geri is all about yoga, healthy eating - and clothes that flatter her shape.
"[She] is finally comfortable in her own skin. She feels better than ever."
Bandmate Emma Bunton credits her slim down to working out three times a week.
An insider says of the mother to Beau, five, and Tate, 15 months: "Emma likes running on the treadmill. She's very happy with her body these days!"
While mother-of-four Victoria Beckham recently confessed that she loves "to snack" on fresh fruit and coconut water, and after giving birth to daughter Scarlet in 2009, Mel C says she feels "more feminine" than ever before, it seems no Spice Girl is as dedicated to fitness as Melanie Brown.
The mother to Phoenix, 13, Angel, five, and Madison, 11 months hikes and reportedly does 600 sit-ups a day, making it easier to slip into skin-tight bodysuits like the Zuhair Murad design she chose for her last performance.
A source explained: "Mel does one-to-two-hour treadmill workouts with playlists made by DJ Lindsay Luv."