Having recently shed 40 pounds, Aguilera attributes her transformation to meticulous calorie tracking and the demanding workout regimen she endures during her performances at her Las Vegas residency.
From TMZ:
The singer belted out her catalog of hits Saturday from The Voltaire at The Venetian, Xtina's strong and slender figure was front and center in a series of tight leotards and thigh-high boots.
After years of scrutiny for her fluctuating weight, XTINA's maintaining a healthy physique ... previously admitting she hated being skinny and loved her booty.
She's clearly now found the secret to maintaining those curves ... and says it's helped with a balanced diet and dedicating herself to boxing, strength training and cardio workouts.
It wasn't all smooth sailing though ... she restricted her daily food intake to 1600 calories on the Rainbow Diet after welcoming her son Max in 2008.
