Unlike most people, Giovanni Enea didn't experience a distinct turning point when he realized it was time to lose weight and get back in shape. "I just woke up one morning and thought, 'you know, let's just try this one last time,'" he says. Enea, 21, a student who is studying computer science in Italy, says he'd struggled with obesity for so long up until that point that it practically felt normal. "I've been obese since can remember. There isn't a single time in my life—except, of course, last year—that I happily saw myself in the mirror," he says. "I thought I was built that way and nothing would ever change."

At his heaviest, around age 19 or 20, Enea says he tipped the scale at a little over 340 pounds. He'd always been active, playing lots of sports like football and handball and even kickboxing, so a sedentary lifestyle wasn't necessarily the problem. "As you know, you can't outrun a bad diet," he says. "I think I averaged about 3,500 calories per day on a normal day, and I was always going out to eat." Eating healthier and leaner, he knew, was where he'd have to start. While trying to decide which diet seemed right, he remembered what's known as CICO—Calories In, Calories Out—less a traditional "diet" than a dietary principle. In short, it's basically this: Burn more calories than you eat. Finish the day in a calorie deficit.

"I knew it would work if I just stick to this simple concept. I actually ate really bad in terms of macros, but I always made sure that I didn't go over 2000 calories per day," he says. His goal was—and still is—to aim for a 1,000 calorie daily deficit. "The process at the start was really painful. It was hard gaining new healthy habits. I've tried countless diets and seen doctors and dietitians. I always had that thought: This will never work, you know it, you can't do it, but I fought hard."

Despite that voice in his head, Enea did indeed put in work, eventually adding a regular gym routine to his regimen. In the first three months, he dropped more than 45 pounds, and says he's steadily lost about 10 pounds per month since then. Since starting roughly a year ago, he's lost a grand total of nearly 130 pounds, down from 340 to 210. "I truly feel amazing," he says, "but I'm not done yet," adding that he's now setting new goals for 2020, which include losing about 30 more pounds and training for a half marathon.

Giovanni Enea

In addition to simply feeling healthier, Enea says he's more athletic, having rediscovered his passion for running and hiking. Asked for advice he gives to those who are just starting out, however, he defers. "Everyone is different," he says. "I can only suggest that you imagine how your life will be different in a year if you start today."