Why so many USA people are suffering from obesity

I was gaining weight a lot this past decade till I went on a Resistant Starch diet, it balanced my blood sugar. I am eating a good amount of healthy fat & protein at every meal now but have eliminated all grains and processed sugars. The grains here are mostly GMOs and are messing with hormones and the appetite. I got a healthy appetite back after only 48 hours on the Resistant starch diet experiment, and I figured when I started it that it would take at least a month or more to notice any kind of difference. I lost 25 pounds in the first 2 months. I eat potatoes or potato starch and other starchy foods every day now, it straightened out my digestion which I figured had something to do with my weight gain. There is an article in FIRST magazine this month about how GMO foods are a cause of obesity....and antibiotics are thought to kill out healthy gut bacteria (resistant starches help create one type of gut bacteria) that help with hormones and metabolism, etc.