A 58-year-old whose job requires hours of sitting lost 75 pounds in 12 months with these simple changes

• A man gained 50 pounds after he quit the army and started driving — and sitting — for a living.
• A fitness and nutrition program designed to reverse diabetes has helped him lose 75 pounds.
• He still sits for long hours, but packs his own lunch and makes sure to exercise 6 days a week.

When Jerry Clark decided to quit the Army, hit the road, and start driving long-haul truck routes 34 years ago, he had no idea what a dramatic impact the career change would have on his body.

"A truck driver is the worst job in the world for health," Clark told Business Insider.

Arguably, no one is required to sit more on the job than a truck driver. And we all know sitting is the new smoking.

Clark spent years tag-teaming across the country with his wife on trucker routes. At one point, before she retired, they were logging 8,000 miles together every workweek. The pair would drive almost three full lengths across the continent each week, eating whatever they could find to sustain them along the way.

"We eat at the greasy spoons," Clark said, explaining the average truck driver's meal plan. "Everything is grease, or fried."

All that sitting and eating greasy food can lead to long-term health issues and body imbalances. Clark developed a stronger left leg from operating his clutch and a stronger right arm from being at the wheel for half of the day. He also gained over 50 pounds over the course of three decades.

An employer-offered nutrition program led to big changes

About a year and a half ago, when he heard his employer was offering free nutrition coaching for people with diabetes through Virta Health, he wondered if he might be eligible to join the low-carb program, even though he has normal blood sugar and doesn't need to "reverse type 2 diabetes," as the company promises. Sure enough, his employer allowed him to try it out.

Clark has lost over 75 pounds in the program and has discovered he has renewed energy for both work and hobbies, including wood carving. He says he's trimmer now than he was when he left the Army in his mid-20s. He's spent the past several months maintaining his weight and working on muscle building.

He's lost over 75 pounds with diet, exercise, and guidance from a coach

"I look pretty dang-on good right now for a 58-year-old guy," he said. "Almost getting a six pack back."

He has also helped his son lose over 100 pounds using the nutrition techniques he's learned, which are in line with some of the recent federal nutrition guidelines, released in January.

This is no coincidence: Virta co-founder Jeff Volek helped draft the Trump Administration's new Dietary Guidelines for Americans, which encourage people to skip ultra-processed foods and added sugar, prioritizing animal protein and "healthy" fats.

Now Clark eats more whole foods than he used to, including fruits, vegetables, and meat. He doesn't fuss too much about fat, especially the kind of fats in nuts, fish, and lean proteins like chicken.

"My journey's not over, but I am getting there," he said.

You don't have to eat low-carb to lose weight

Many nutrition experts say low-carb ketogenic diet plans like the one he's following are not right for everyone. Generally speaking, people without diabetes could benefit from more fiber and whole grains than this style of eating typically provides. Still, there are a few nutrition basics that just about every "healthy" diet plan agrees upon. Virta's low-carb strategy is no exception. Plants like fruits, vegetables, nuts and seeds are good. Extra sugar and empty calories from white bread, cakes, and sodas? Not so much.

"There's this base of knowledge which is pretty translatable between different diet camps," nutrition scientist and ultra-processed food researcher Kevin Hall, co-author of the book "Food Intelligence," previously told Business Insider. "All of the camps can sort of agree on non-starchy vegetables and lowering added sugar."

Hall has performed studies showing that low-carb diets are not any better than low-fat diets, when it comes to how much fat people lose. Low-carb diets can be helpful for stabilizing blood sugar in patients with diabetes, but it's the quality of a person's diet that matters most.

"For the vast majority of people, it's really the processed and refined carbohydrates that they should avoid," Hall said. Carb-forward beans and strawberries, loaded with fiber and antioxidants, are great choices for most people.

Another big reason for the success of Virta patients like Clark, according to former US Food and Drug Administration commissioner Dr. David Kessler, is the "built-in accountability" that patients get from Virta's intensive, personalized coaching model, as he explains in his new book "Diet, Drugs, and Dopamine: the New Science of Achieving a Healthy Weight."

As for Clark, he has a few evidence-based nutrition moves he credits with helping him make the lasting diet changes that he plans to stick to for the long haul.

Here are his 7 best pieces of diet advice:

Eat more vegetables

When Clark drives his 600-mile route from North Carolina to West Virginia and back overnight, he brings his own "lunch," or gets a few essentials from the supermarket. No more greasy spoons. Broccoli, leafy lettuces, and cucumbers are now staple foods at his house for lunch and dinner.

"I'll pack a chicken breast and some broccoli, and then at around midnight when I get to a truck stop, I'll pull in and pop it in a microwave, and I'm pretty happy," he said.

With the help of his nutrition coach, Clark started meal prepping and shopping around the perimeter of the grocery store, a classic pro-nutrition move.

"Most of the crap is in the middle," he said.

Change your palate — it takes time, but curbs sugar cravings in the long run

Clark has found that over time, he is craving less sugar. It helps that he doesn't keep junk food in the house, since it's typically loaded with sugar, saturated fat, and refined flour. Now, he finds he wants veggies and other whole foods, including deer and rabbit for dinner, and blueberries as a sweet treat.

"Food itself tastes good as long as you change your taste buds," he said. "It's going to take you a month for your taste buds to change."

Studies suggest that most of our taste buds regenerate about every 10 days, but some take longer to turn over, around three weeks or so.

Avoid 'added crap' like refined flour and sugar

Clark said he still enjoys many of the same foods he used to eat, he just prepares them differently now.

"You can have the same stuff," he said. "You can't have all the added crap that America puts on it."

For him, that means rotisserie chicken instead of fried chicken and homemade ice cream made from whipping cream and eggs, with far less sugar than store-bought tubs.

Though the Clark house generally stays away from fast food and ultra-processed groceries now, there is some occasional wiggle room from time to time for a low-calorie, low-carb, ultra-processed dessert like Cool Whip with Jell-O. Even that's pretty rare these days, Clark said.

Use your hand to measure meals

Clark says one of his biggest challenges in the program has been learning not to overeat. It's something he's talked over with his coach.

"I am an over eater — that's my biggest problem," he said. "I like mass quantities of food."

Obesity medicine doctors say that's likely because Clark's "enough" point became dysregulated: as he gained weight, his brain sent signals to his body to eat more and store more fat, in protection mode against starvation.

With guidance tailored to his body size and a kitchen scale, Clark started measuring out a recommended 7 ounces of protein for lunch and dinner. But his coach also gave him a quick shortcut for thinking about his portion sizes.

"Your hand is your best tool," he said. "The palm of your hand without your fingers is approximately 7 ounces, that's a portion of meat."

Don't obsess about the numbers on the scale if you know things are moving in the right direction

When Clark started adding regular weightlifting into his workout routine, the number on his bathroom scale stagnated. His coach encouraged him to focus on other metrics instead.

"My muscles are getting bigger, and my waist is getting smaller," he said. "My coach said, 'If you're happy with what you see in the mirror, be happy.'"

Build your tribe

Clark has been openly sharing his nutrition strategy with family and friends. His son has lost over 100 pounds using his techniques, and one of his long-haul trucking buddies has lost over 80 pounds.

"We talk every night: 'Hey man, what'd you eat today? Did you work out?'" Clark said. It's another time-tested strategy: couples, friends, and families who lose weight together tend to have better long-term success.

Now, Clark's wife is getting interested in the program.

"She sees me, and she's like, 'Man, you're doing really good. I want to try that.'"

Treat yourself to an hour of movement every day

Finally, Clark has developed a new routine of working out 6 days a week, alternating heart-healthy cardio (like a run) with weightlifting every other day. Building muscle mass is a great way to maintain the right kind of weight loss, encouraging the body to shed fat instead of muscle. If he's hungry after, he grabs a protein shake "to fill my muscle stores up."

"I told my wife: one hour a day, I don't want anybody to bother me," Clark said. "No phone calls, no 'honey, you got to fix the toilet, mow the grass.'"

Now, he looks forward to the dedicated, sacred time for workouts.

"An hour out of a day? Come on. That's nothing. Give it to yourself and then make it work," he said.