HOUSTON -

'The Voice' coach Christina Aguilera knows how to wow a crowd with her vocals, but no one expected her reported 50-pound weight loss in a matter of months.

She's been open about her struggles with weight since giving birth five years ago.

Personal trainer Derith Cass with The Houstonian Club told Local 2 many of her clients can relate.

"It's kind of a joke that we'll ask clients, 'Well how long has it been since you've had the baby?' and they'll say, 'Well my child is 15 years old,'" said Cass.

So how did Aguilera lose all that weight?

She's known to work with a Hollywood trainer who focuses on yoga, strength training and cardio.

Cass said the key is finding the right combination for your body and making the most of the time you have.

"We really push strength training and cardio because for both of those types of exercise, you're building muscle and you're also burning fat which is what gives that overall defined, toned appearance," Cass explained.

Another big secret to Aguilera's success is a 1,600 calorie a day meal delivery plan.

Christina picked the meals online.

UTHealth Clinical Dietician Carol Wolin-Riklin said a diet program that's high in protein, low in carbs, fried and processed foods is a great way to kick start weight loss.

"Typically, most people focus on getting at least four ounces of a protein -- be it fish, beef, chicken or low fat cheese -- which is a little bigger than the palm of your hand or a deck of cards, and if you eat the protein first, that tends to help fill you up and satisfy you," Wolin-Riklin explained.

Pre-packaged meals can cost $5, $10, $12, but dietitians say that's about what you would spend on a fast food or restaurant meal. So the idea is to pick up a few and get an idea about portion control.

"It gives you an idea of how to make your meal so that you can buy containers and portion your own out so you can make your own at home for less money," Wolin-Riklin added.

She also recommends calorie counting apps and online programs such as My Fitness Pal and Calorie Count by Fat Secret.

Fitness and diet experts said there are no short cuts. A healthy diet and regular exercise go hand in hand when it comes to getting to your goal weight.