It's not impossible, sir, just much harder. Americans are not more obese than Europeans because we are lazier etc., it's because our food is much worse, starting with the antibiotic-, hormone- and corn-infested garbage they sell us as meat.
It depends where you live in the USA. As with most problems in the United States, it starts and ends with poverty.
It's pretty well documented that grocery stores in general have razor thin profit margins (a couple percent). Traditional grocery stores that offer a wide variety of prepared foods, raw staples, produce, and fresh meats are becoming scarce in poorer areas. USDA even has a name for these regions, "food deserts" ...
There are several reasons why, but the biggest is the huge growth of dollar stores (again - poverty driven). About the only thing you can buy at a dollar store for a dollar is a pre-processed factory-excreted single or family size serving of something with a shelf life measured in months if not years.
For middle class or better areas, it's not harder to buy healthy food, and it's actually less expensive. Compare a TV dinner from the freezer aisle, or a box of microwavable frozen Jimmy Dean egg sausage biscuit sandwiches ... to a box of pasta, a bag of rice, a bag of beans, and some cheap but healthy cut of meat. A nicely marbled ribeye is obviously costly, but a 2 pound package of plain chicken breasts is far cheaper on a dollar/gram-of-protein basis, than the Cup O Noodles, Slim Jim, or can of Dinty Moore stew at the Dollar Store.
Time to prepare foods is another major factor. Europeans, with their 35 hour work week, and less time wasted commuting alone in cars (drive-thru coffee/breakfast anyone?), simply have more time to prepare their own meals.
Beyond the above, laziness absolutely is a core issue. Middle class and wealthier people (with more leisure time) tend to be less obese than poor people. They absolutely can buy healthier food, they just choose not to. Sweet fatty foods are tasty and easily available. They eat them because they're tasty and convenient.
When it comes to obesity and other health issues, these are far more significant factors than any leftover traces of growth hormones that were injected into a cow two months before slaughter. High fructose corn syrup is easy to avoid if you don't eat or drink sweetened pre-prepared foods ... but dollar stores sell grape soda, not grapes. Antibiotic overuse is a separate issue. Antibiotics have half-lives measured in hours, so a chicken breast in a grocery store isn't going to have a non-homeopathic dose that could affect a human who eats it. (And antibiotics don't cause obesity anyway.)
The anti GMO, anti growth hormone, anti antibiotic "organic" food movement in the United States is a racket that mostly preys on uninformed people with disposable income to pay for those marketed-as-premium products. We have outstanding quality food available in the US. For all the contempt I have for certain 3-letter government agencies, the FDA is one that does a good job. Our food is clean, safe, cheap, and plentiful. We're a fat country for cultural and economic reasons.