David Bostik once weighed 346 pounds. Two years after joining a gym in college and hiring a personal trainer, he lost 140 pounds. He is now a personal trainer himself helping other people gain control of their health and fitness.

Luckily for me, Bostik opened a Fit Body Boot Camp in Andersonville this past March. Not only is it close enough for me to walk to, but I get a tough, sweat inducing workout that only takes a half hour.

After a couple of minutes of warm-up, FBBC puts its members through a HIIT circuit. A typical session involves one exercise at each station for 40 – 60 seconds, or two alternating exercises, for four rounds. The six stations involve, among other things, TRX, ropes, medicine balls, box steps, kettle bells, free weights and body weight exercises.

While I initially tried FBBC because it is only 30 minutes (instead of the usual 45 – 60, which can sometimes seem like an eternity), I wondered if the shorter class would be enough of a workout. My doubts were quickly put to rest as the non-stop, strenuous pace had me feeling wiped out and a little nauseous on my first day.

Explaining the concept to me, Bostik, who has been offering 30-minute workouts at his personal training studio for eight years, said, “Time is the most valuable thing we have. I trained for five or six years doing hour sessions and I realized that the first five to 10 minutes would often be a warmup, the last 5 to 15 minutes would be a cool down stretch and then in between there’d be a 30 to 40 minute high intensity, or somewhat high intensity, workout. If someone’s working hard enough they really can’t go past a certain point; 35 minutes is more than enough.”

As for FBBC specifically, Bostik further explained, “The science in recent years is slowly coming out to show that the high intensity interval training is the most beneficial type of training because it peaks your heart rate; it gives what we call the afterburn effect. So, you may burn 300 – 400 calories during a session, but your metabolism is peaked throughout the rest of the day. So, it’ll help you burn an extra, five, six, 800 or 1,000 calories the rest of the day because of the way your metabolism is fired up.”

He recommends at least three days a week of Fit Body Boot Camp to see results, but many of his members attend four to six classes, in addition to doing yoga, Pilates, strength training or cardio. I like to pair the boot camp with sprint workouts, but whatever route is taken, one or two days off to rest and repair your body is encouraged.

FBBC recently completed a four-week challenge, that included unlimited workouts, a detailed meal plan and at-home workouts in case of missed classes. Progress reports and food journals were also required. “It’s a very, very results and accountability driven program,” he said. And one that will return in September.

The results were pretty impressive, as, in one month, the gym saw clients lose up to 21 pounds, while others lost up to 15 inches and still others shed up to five percent body fat. But it’s not all about weight loss, as Bostik has also seen positive results by way of, “Just living better, feeling better, sleeping better, [being] more successful in careers, [having] more energy. All kinds of stuff like that. It’s great.”

Knowing I can get my workout done in just 30 minutes often prompts me to get off my couch when I’m not really feeling it, but sometimes that’s not enough. So, I asked Bostik his advice on staying motivated.

“Set goals,” he offered. “That’s probably the most important part. Whatever they may be. Short-term and long-term goals. If you don’t have a goal it’s very easy to lose track of what you’re doing and why you’re doing it. And then, celebrate victories. A lot of people don’t do that. It could be something as simple as putting on a tank top and noticing your arms are a lot tighter and not jiggling like they used to. That’s huge. That’s awesome. Or you’re sleeping much better at night and have more energy throughout the day. Celebrate the victories, set goals and just keep pushing.”

Fit Body Boot Camps can be found throughout the US as well as in Canada, Australia and the UK. In addition to the Andersonville gym, Bostik has another location in North Center, as well as his personal training studio in Lincoln Park. Try FBBC free for 3 days or check them out through Class Pass.