How This Man Lost Nearly 300 Pounds Using Instacart

Feeling like his desk job wasn’t keeping him active enough, Antonio Martinez took a part-time job at Instacart to get moving.

In five years, Antonio Martinez went from weighing more than 500 pounds, to weighing about 220 — just by shopping at the supermarket.

Martinez attributes the dramatic weight loss to working for Instacart. 

The grocery delivery service lets customers select items from a local supermarket on their app. A shopper picks them up and delivers them straight to their door.

“I wasn’t really comfortable with how I was moving. I was always just sweaty, couldn’t really breathe right," Martinez told "I couldn’t really do much, to be honest. I was so comfortable in my job. Just at my desk, didn’t have to move, not a lot of movement."

Feeling like his desk job wasn’t keeping him active enough, Martinez took a part-time job at Instacart to get moving.

"I remember just walking through the store, it was a struggle. I was just, like, sweating, I could barely walk. I remember I got in my car, I rested and was like, 'I'm not so sure about this.' This may be a little too active for me," he said.

When Martinez's wife, Gaby, told him she was ready for kids, it sparked a change.

"To be honest, I was just basically like, my wife, she takes care of me. I'm not doing much of anything. What am I gonna do? I won't be able to play catch or go to amusement parks or anything with my kid."

Martinez continued delivering for the app, becoming a full-time employee. He credits it with helping him break some unhealthy habits and adopt some new ones.

"It started with like, ‘Ooh, what is chard?’ I didn't know what that was ... not part of my diet, was not part of the Mexican diet or anything like that so I didn't really have it," he laughed.

After a year, Martinez had lost a full shirt size.. He’d started to feel good about shedding some pounds, but realized he still had a ways to go.

"I went and bought a 420-pound scale from Walmart and it didn't take my weight."

He visited his doctor, where two more scales read "error."

A third scale registered.

"I weighed myself on there and it said 520. And I was like, ‘What the — ?’ This is crazy. Because I thought I was doing good and I was, I had lost a shirt size. But I was still so big and I didn't realize it."

So he turned back to his phone.

"What I started doing is just looking at the orders. So I would see somebody who was fit and would be like, 'Well, what are they eating?' And I just started trying different foods from them."

It would be a simple question with one of his customers on the keto diet, a low-carb, high-fat plan, that would prove to be the true catalyst.

"I'm like, 'You look great, I don't know why you're so strict.’ He's like, 'Yea, I was really big, I don't wanna get that big again.' And I was like, ‘Well, how big were you?’ And he was like,’ I don't want to offend you, but I was your size.’ He showed me a picture and I was like, ‘That's what I have to do.’"

Martinez initially lost 100 pounds after going keto and an additional 190 pounds after bariatric surgery.

As he dropped the weight, Martinez rose up the ranks at Instacart. Now he's in charge of in store operations at about a dozen locations around Chicago.

He never kept in touch with the man who he said forever changed his life.

"I wish I did and I always wondered and I go back to look at my orders."

Martinez has this message for him: "Thank you for motivating me."

Now weighing in at 220 pounds, Martinez is still living a keto lifestyle, and has advice for anyone else who may need a little push.

“Start whenever you get that urge. We all get this motivation sometimes like, 'I want to lose weight, I’m gonna go to the gym, but I’ll start Monday. It’s Friday, let me enjoy the weekend, I’ll start Monday.' My thing is, whenever you get that feeling that you wanna do the change, implement it right there,” he said.