Teddy Bass has been training Hollywood stars for over 20 years, with a famously fit client roster that includes Cameron Diaz, Lucy Liu and Christina Applegate. The celebrity personal trainer shares with LivingHealthy how he keeps his celebrity clients in tip-top shape.

First off, if you want an A-list body, plan on working out a lot. “Determining how often and the intensity always depends on the client’s goal,” Bass explains. “On average, 3 to 5 days a week is typical and that can range from a cardio-based session and Pilates to strength training that focuses on the core.”

Before a workout, Bass makes sure his clients are hydrated and haven’t eaten a heavy meal for 45 minutes. “If they need energy, I suggest a KIND snack or fruit, but to reduce body fat, it’s better to work out on an empty stomach.” Within 45 minutes of the session ending, Bass recommends having a protein shake “for the rebuilding process.”

For an effective workout, Bass explains that variety is key. He likes to push clients so their bodies must constantly adjust to new and different demands. He is also big on proper form, uses plyometrics elements to keep the heart rate up and is a huge fan of multi-joint movements (such as doing kicks when in plank formation or boxing jabs with lunges). “They are great for time restraints and you are able to do them with little or no equipment,” says Bass, who also likes “squats with a shoulder press, reverse lunges with a twist, push-ups alternating lower body kick backs and fire hydrants, and plank with straight arm back rows into sumo squat stance with bicep curls.”

When it comes to working out, Bass admits that stars are just like us, in that they have a love/hate relationship with exercise. “Most love jump squats, reverse lunges with alternating overhead reaches, Pilates foot work on the reformer and all core work—from planks to traditional unilateral oblique work. They hate burpees, long planks, walking lunges, assisted pull-ups and springs.”

Bass emphasizes that it’s important to adapt your workout (and diet) as you evolve if you want to achieve agelessly fit figures like Diaz’ or Applegate’s (both actresses have worked with Bass for several years). “Our bodies change on a daily basis—being conscious of that allows you to really listen and know what's needed. Sometimes arms need more work, sometimes posture and core need more awareness. I think the key is proper eating and making sure you stay active. When your cardiovascular system is challenged, this helps increase bone density and reduce stress.”

During the days you aren’t exercising, Bass suggests doing anything that will keep you moving and active without making you feel as though it’s a challenge or burden. “We have to remember [that fitness] is not all aesthetics—we have to consider what it does for our mood, blood flow, energy and brain. It’s a win-win for all when it’s a way of life and not a fad.”