What if your boss told you to gain 10 kilos of muscle and lose a third of your body fat? Most of us would end up in the unemployment line, but Ryan Reynolds did as he was told to prepare for his role as a cut vampire killer in Blade: Trinity back in 2009- and best of all, he has managed to keep it and train even harder for his role in Buried.

Rodrigo Cortes, director of Buried on Ryan Reynolds

“Buried was shot very quickly, demanding an enormous amount of concentration, enabling the film itself to feed on the precise, tense and rigorous energy felt on the set. There were six minute long takes with no cuts, creating the conditions for Ryan Reynolds to achieve an absolutely organic performance, allowing his emotions to grow and flow, bringing forth and spilling out like a torrent. The elements at our disposal were, objectively speaking, minimal, but far from considering that a disadvantage, we thought of the limitation as our greatest strength: only the essential remained.

Ryan went back to Los Angeles a physical wreck; no doubt he had to justify to US customs officials why sand trickled to the floor whenever he blinked. His sense of commitment went simply beyond the call of duty. 17 shooting days, no more. 25 shots each and every day. Sometimes 30. Or even 35. How did we do it? I don’t even know myself... which I guess can only mean we didn’t do it.”

Here are his tips for sculpting a six-pack on a full stomach

Eat More

"I attribute my results mostly to nutrition," Reynolds says. (See "What He Eats," below, for a sample menu.) He ate every 2 to 3 hours to burn more fat. "Your body doesn't need to store fat for energy if you're feeding it all the time," explains Bobby Strom, Reynolds's Los Angeles-based trainer.

Mix It Up

"I gained a lot more muscle mass when I went on creatine," says Reynolds. He also took L-glutamine, conjugated linoleic acid (CLA), whey, and a multivitamin.

Go For Bulk

Reynolds doesn't have a personal chef, so he cooks meals in advance. For instance, he'll make a large supply of Irish steel-cut oatmeal and freeze it. That way, the most important meal of the day requires the least work.

Carve With Carbs

"Never do any of that carve-starve crap," Reynolds says. Instead, watch the clock. He ate most of his carbohydrates post-workout, and none after 8 p.m.

Think About Yourself

"If you hate your workout, you're not going to do it," explains Reynolds. Customise your fitness plan to meet your needs. He found it "meditative" to do ab exercises first instead of last.

What He Eats
Breakfast 2 eggs, some "good" fat like a spoon of almond butter or slice of avocado, and 1 cup of oatmeal with applesauce
Midmorning snack protein bar
Lunch tuna wrap or chicken and salad
Midafternoon snack protein shake (whey and water), protein bar, or apple and almonds
Dinner broiled fish or chicken, brown rice, vegetables, and salad

Evening Snack protein shake

Buried is available on DVD & Blu-Ray on now