Trainer reveals secrets to getting celebrities in shape for the Oscars

BEVERLY HILLS, Calif. (KABC) -- It can be a tough turnaround to look your best right after the holidays, but many celebrities have to get themselves in shape for award season.

Jennifer Lopez, Sofia Vergara and Kim Kardashian are a few who have turned to trainer Gunnar Peterson to help them walk the red carpet without fear.

"Hopefully, they're not coming last minute and trying to fix this on the fly," Peterson said.

Celebrity or not, he demands a lot of his clients.

"That whole soft hand, kid glove thing doesn't really fly," Peterson said.

For women, he is a big fan of weights.

"I push all the girls to lift a lot of weight. Women need to lift weights," he said.

As for fears of bulking up, most don't eat enough calories, push hard enough or stay at it long enough for that to happen.

Yet, strength training provides the fat burning effect and tone they want.

Peterson also offers key components for when they're not in the gym with him. First up, he wants them to put down the juice and pick up a fork.

"Not only calorically are you going to be at a deficit, but you're going to be lacking other nutrients you may need to give 100 percent in the workout," Peterson said.

Pass on carbohydrate extras and focus on protein and produce for this time period.

Along with nutrition and fitness, focus on two other elements: stress reduction and sleep.

"If your stress levels are peaking, your cortisol levels are high, your body is breaking down. You've got to counter that with exercise, with sleep and with good nutrition," Peterson explained.

Why is sleep important?

"They've got to rest. They've got to recover. It's the one they overlook," he continued.

The bottom line?

"Make good choices at the table, make sure you're getting enough sleep, make sure you're hydrating," Peterson said.

His hydration equation: One ounce per pound of body weight, which is more than you're most likely getting.