London: Britney Spears may have shed extra pounds by drinking her favourite Lean 1 shakes, but the diet may have hazardous consequences on her health, warn experts.
Britney, 28, lost 10lb in a fortnight by replacing two daily meals with Lean 1 shakes - then eating salad and protein for dinner.
However, the drinks dubbed "better than liposuction", could trigger hair loss, constipation, heart attacks and bowel cancer, say doctors and dieticians.
Lean 1 provides nearly 400 calories a day and contains the herb hoodia - which is said to boost metabolism and suppresses appetite - plus vitamins and minerals and plant extracts.
"It``s completely safe," News of the World quoted creator Bill Romanowski, a former American footballer, as saying.
He added: "It gets rid of hunger pains using a form of hoodia nobody else has access to. They literally keep you from getting hungry.
"My big break was when Britney lost all her weight before her tour last year by drinking my shakes, and told all her friends about it. It spread like wildfire."
However, British dietician Gillian Killiner warned: "The lack of protein makes muscles waste away and you risk heart and kidney failure.
"The entire working process of the body can effectively break down."