Rihanna takes 'rocket fuel' for work patternLos Angeles, April 6 (AZINS) Singer Rihanna's body clock is reportedly a "total mess" from her long days in the studio and she has been refuelling herself with alcohol and Diet Coke.

According to a source, the 27-year-old regularly works long days in the studio and it has disturbed her sleeping pattern, reports femalefirst.co.uk.

“Her body clock is a total mess from working 18 hours a day in the studio,” OK! Magazine quoted a source as saying.

“She fills up by drinking a crate of Diet Coke - washed down with Budweiser! (She) simply forgets to eat.

"She calls the combo 'rocket fuel' and while she enjoys the odd shot of tequila or vodka on the rocks when out partying, in her opinion, nothing can beat her beer and fizzy soda mix,” the source added.

Meanwhile, Rihanna recently admitted that she hates vegetables and prefers to enjoy helpings of pasta and cheese.

She said: "I eat tons of mac and cheese. I know I shouldn't but I do. I've had some time off from keeping fit but I'm really get back into working out now and eating cleaner...I hate vegetables but I'm learning how to incorporate them one by one into my diet and drown them with other flavours so I don't have to taste them.”