Transcript for Teacher who had heart attack inspires 1,300 colleagues to try 10-day plant-based diet
We'll move on to this morning's "Gma" cover story. It's about the teacher trying to spark a new movement on health. Doug Schmidt issued a ten-day challenge to eat a plant-based diet and already over a thousand people have joined it and a support group on Facebook. He resolved to make the change after a near fatal heart attack. He wasn't even 50 and another scare that same year and knew he had to make a big change. Boy, did he. 60 pounds later he says eating a plant based diet has not only transformed his physical appearance but overall wealth and wellness and convinced over 1300 people to join him. He is the teacher inspiring a revolution with his incredible weight loss and new lease on life. I've had people who they came to me and said, Doug, I hear maybe you can help me with this issue. Reporter: It started in 2008 after he called a widowmaker heart attack at age 49. All of a sudden I got a tightness in my chest and then the nausea kicked in. Reporter: At 225 pounds he knew he had to make a big change and put aside his favorite foods. Maybe a couple of eggs, a couple strips of bacon, I loved my cheese. For dinner, nothing like a good baguette with bruschetta. Side of steaks, some mashed potatoes. Have a glass of wine. There was always cookies. There was always cake. There was always pies. Then snack on some ice cream before going to bed. Equal portions one cup to one cup. Reporter: Instead he switched to a plant-based diet. It's hard to change those. Reporter: Diet centers around plants have become a health food craze and Beyonce and Jay-Z are reaching for the greens. The evidence is overwhelming. You can use diet and lifestyle to treat and even reverse disease. Reporter: 39% of Americans say they want to eat a more plant-based diet and it can make a bigference when it comes to improving health. Diet is probably the single most important influence on health across the lifespan in the United States today. Reporter: For Schmidt his new eating habits helped him lose 60 pounds over three years. My day starts with a bowl of oatmeal with flaxseed, hemphill-mapps seed, banana, strawberry, raspberry, blueberries. Reporter: He no longer has to take medications, he says. I feel truly like I'm in my 20s. I have so much energy. Reporter: Now 59 he's using some of that energy to lead more than 1300 of his teaching colleagues in a ten-day jump-start your health challenge. Doug is there day and night for people. Reporter: Using a Facebook group to offer support when times get tough. This changed my life and look at what I eat differently. Everybody needs that person to lean on and if I can be that, terrific. Reporter: Clearly Doug is doing something right. Two years ago he had 30 participates. Last year 65 participants. This year as I sai more than 1300 from school districts all over New York state and guidelines are simple. Ten days of whole food plant based no oil and already planning a celebration to end the challenge where he says he hopes to convert people to use this long term. Let's talk about with Dr. Jen Ashton. What's your take? I think there's definitely data that supports the heart health benefits of a plant-based diet, however, there's more recent data that shows that our cholesterol levels say is not totally determined by eating a lot of eggs or steaks or the foods we eat so there's been some -- Genetics. A lot is genetics but a lot of heart disease and heart health is preventive and it's lifestyle based so when you talk about plant based diet the reason it can be so healthy is it's generally low in red meat, low in animal protein, it's low in those refined sugars and starches which is not great for us and then it's very colorful. Very high in leafy greens, fruit, vegetables, whole grains and the's always going to be good. Low in red meat and animal protein. One challenge how do you get the protein into your diet. So many people who go completely plant based by definition wind up taking in a lot more carbs and by the way if those carbs are in the form of bad sugars, that is definitely not good for your heart so you want to go for things like we have in front of us, the legume, beans, hemphill-mapps seeds is one of my favorite, leafy -- Nuts can be good in moderation. Whole grains, cruciferous vegetables like cauliflower and broccoli have protein in them. You have to make sure you're getting enough protein and in general some plant-based proteins can be lacking in some amino as sits. Not just about moderation but motivation. The best part about what Doug is doing. Absolutely. Whether that motivation and inspiration comes from within which is always ideal or ext externally in the form of a support group the key is making changes that are going to really affect a major change in your life anticipate that's what you see here. The other thing, George, that jumps out that I want people to know it is a major red flag in terps of your own risk for heart disease. If you have a family history of a heart attack in someone before the age of 50, most people don't know that. That is a red flag so you could say, well, my brother had a heart attack when he was 48. You need to get yourself to a cardiologist and be screened. That's when you want the extra screening? Absolutely, that's a huge red flag. Jen Ashton, thanks very much.
This transcript has been automatically generated and may not be 100% accurate.