Celebrity trainer Harley Pasternak has worked with some of the fittest bodies in the business 鈥 Kim Kardashian West, Adam Levine (Pasternak calls him 鈥渁 beast鈥), Ariana Grande (鈥渘ever misses her step goals鈥), Jordana Brewster (鈥渨orks so hard in the gym鈥), to name a few 鈥 but his health advice is surprisingly simple. The former Canadian hockey player, who ran a superhuman lab before starting a personal training business, says the five most important daily habits for a healthy life are: Get 10,000 steps a day, get seven hours of sleep, eat five meals with protein and fiber, do five minutes of resistance exercise, and unplug for an hour.

As a Fitbit ambassador, Pasternak is a big proponent of moving more. After studying the 10 healthiest countries in the world, he found the thing they all had in common was that people, on average, walked over 10,000 steps a day (vs. Americans, who average around 4,000/day). He also says the wearable device has revolutionalized the way they work with clients because they can now keep track of what people did outside the gym to give them credit in addition to what they did in it. He even gave his client and former Fitbit ambassador Julianne Hough her first Fitbit (鈥渟he owes me $149,鈥 he quips). We chatted with Pasternak about staying healthy, mistakes to avoid, and the weirdest body part he鈥檚 had to train.

harley pasternak and jordana brewster

Brit + Co: What are some simple things you can do to stay healthy during the holidays?

Harley Pasternak: The same things you do to stay healthy all year. Move when you can, don鈥檛 move when you shouldn鈥檛, and make smart eating decisions. The idea that we hibernate this time of year and we tend to move less and we tend to stay inside more鈥 I think it鈥檚 really important that we move more. You burn more calories and more fat in a cold environment than a warm one. So this is a great time of year to get outside and go for a great walk because you鈥檒l be doing even more for your metabolism and your physique than if you were doing it in a hot, sweaty, environment. And that鈥檚 something to embrace. There鈥檚 a difference between a blizzard and just a cold night or a brisk day, and I think you should go outside and definitely walk more.

I think there are a lot of parties happening this time of year, and even when you鈥檙e not partying, there鈥檚 a lot of temptation. There are holiday baked goods, there are companies that make celebratory chocolates for this time of year 鈥 so for me, I like to tack on an extra 1,000 steps a day basically over December and just be a human. If you want to take a bite of that gingerbread cookie, do it. You should know what it tastes like. Don鈥檛 have the whole thing, but definitely do it. Someone made it, it鈥檚 probably delicious, you can only get it this time of year, you鈥檙e good.

I think sleep is really important. There are a lot of celebratory events this time of year鈥 [make] sure that you don鈥檛 have to be the last one to leave the party. You don鈥檛 have to drink yourself silly and eat yourself silly. Pick one, and don鈥檛 do it more than twice a week. Make sure you pick your party or your event or your celebration and don鈥檛 make it a month long thing.

B+C: You鈥檝e talked about the importance of walking in losing weight 鈥 is it really that easy?

HP: I think walking is the most important thing you can actively do to transform your body and your health. I think that it doesn鈥檛 require any equipment, it doesn鈥檛 require a special machine or building, you don鈥檛 have to carve time out of your day to do it. It鈥檚 a game changer. We have a lot of clients who鈥檝e done pretty radical extreme intense things over the last several years to get ready for film roles, and I myself was the one telling them to do them often. And now [it鈥檚] how do you do things smart rather than just hard. Like getting people to stay at a hotel a mile and half from my office, walk to my office, roll calls along the way, get some fresh air, come to me for 25 minutes, and then turn around and walk back. As opposed to taking a car service over, being there an hour before, strapping themselves to an elliptical, and sweating their butt off in a hot building. It鈥檚 really about living life and moving in a natural way, and walking is the ultimate of that.

B+C: What鈥檚 the biggest mistake people make when trying to get healthy/get fit?

HP: I think they do too much too quickly too hard. They depart from their normal lifestyle. If you decide one day, I鈥檓 going to get into shape, I鈥檓 going to be a raw vegan and run a marathon and do CrossFit, you鈥檙e doomed to fail. If you say, you know what I鈥檓 going to do, I鈥檓 going to walk around the block that I live on once before I go to work each day. And then next week when I come home from work, I鈥檓 going to walk around the block one more time. You slowly change certain aspects of your life and as a result, these are sustainable things. So if you used to do 6,000 steps a day, you may go to 8,000 and slowly get that up to 9,000 and 10,000 and beyond. That鈥檚 a better way to go than just one day going from being sedentary your whole life to saying I want to do 14,000 steps a day. Also using your Fitbit as not just a motivator but really as a way to keep checks and balances so you don鈥檛 go overboard.

B+C: What鈥檚 the weirdest request you鈥檝e gotten from a client?

HP: We were doing a film called Highwaymen with Jim Caviezel. A lot of it is him driving a car, and it鈥檚 these close-ups. They wanted us to make his forearms and his hands way more muscular because the camera was always on the steering wheel. And I just nodded, I鈥檓 like, 100 percent, we got a forearms/hands program we鈥檙e going. There鈥檚 no such thing. That might have been the strangest.

B+C: How do you make sure each client is getting the workout that鈥檚 best for them?

HP: About 90 percent of a program applies to most people, but we have individual differences from injury history to fitness status, which would dictate personalization. I have the ability to communicate directly with clients or my staff talks to the clients, so it鈥檚 easy for me. The data I get from my clients is really helpful. So every morning I wake up I know exactly how many steps every one of my clients in the world did the day before, how many calories they burned, how intense those were, how they slept, what time they went to bed, what they ate. I have amazing data where I鈥檓 able to manipulate their program accordingly.

B+C: What is your favorite workout/exercise?

HP: I walk 鈥 literally, for me, it鈥檚 meditation; it鈥檚 not even exercise. It鈥檚 how I think, it鈥檚 how I communicate, it鈥檚 how I listen to music, it鈥檚 how I catch up with my friends and my family. It鈥檚 my time. And no one can find me. I actually will walk to things in lieu of driving whenever I possibly can. And if it鈥檚 a very far thing and I just get tired, I鈥檒l stop and call an Uber. I just walk as much as I possibly can.

What are your best healthy habits? Share them with us @BritandCo.

(Photo via Astrid Stawiarz/Getty)