Aniston and Theroux recently jetted off to the tropical destination to celebrate the two-year anniversary of their engagement and Theroux's 43rd birthday.
Ingber has a slew of celebrity clients who come to the renowned yoga instructor to get an amazing body like Aniston, 45.
"Jen's a very consistent exerciser and eater," Ingber told ABC News. "But when she has something she needs to focus a little more on, she just tightens it up a little bit."
For example, before a trip where she is showing off her fine physique, she will cut down on the snacks.
"She won't have the extra chips," Ingber added. "It's kind of like just being disciplined, she's like anyone else that she goes through those times when she can lose a little but pretty much, she's always in great shape."
As far as how the yoga routine changes, Ingber said it's about the cardio.
"We up the cardio a little bit, if she's looking to sort of trim down," she said. "So we add a little more cardio to the yoga, but also what she puts into her body is essential. That really is 80 percent of it ... it's not a big deal if you have a bite of this or that if you are mostly eating well."
Ingber said for Aniston or anyone for that matter, there's no way to spot reduce, so it's all about being more disciplined and getting into shape overall. But like any women, the "Friends" icon definitely has areas she likes to focus a little on.
"She focuses on butt exercises for sure, I'll add some squats into the yoga routine," She added. "For me, there's no better thing to lift your butt than squats. Pretty much, that's gonna do it ... she likes to focus on that like most women. Most of us want that area a little higher."
She continued about Aniston, "she's an incredibly inspiring woman, an incredibly positive person, it's so obvious, everyone that works around her is doing really well, it's a lot because of her positivity is very contagious."
Ingber spoke to ABC as part of her collaboration with Silk soy milk, including five tips to get into shape for all people.
One of these tips include hydration with water, something Aniston has been a promoter of for years.
"Jen is definitely somebody that has encouraged me to hydrate, she is a hydrator from way back in the day," Ingber joked. "That's definitely one of the tips I use because I have so much more energy when I drink. When you stay hydrated, you’re not as hungry. Sometimes when you think you're hungry, you're actually thirsty."
Ingber recommends you drink half your weight in ounces of water. "So if you're 140 pounds, then 70 ounces a day," she said.
"The next tip is energizing with a 20-minute yoga flow," she added. "The cardiovascular of yoga, it gets the heart pumping, all the blood to the extremities, it synchronizes the breath with the movement. I recommend 20 minutes of a yoga flow, incorporated into your day."
She also recommends a more plant-based diet, especially when it comes to getting your daily protein. She stresses you don't have to be a vegetarian, but lean toward plants for protein.