Actually, only about 1/3 of Americans are medically obese, and although total 2/3 are considered overweight, those numbers are probably not very accurate, seeing as how they are based off the BMI system, which only uses weight and height and does not account for muscle mass or different body types. For example, Tom Cruise is considered overweight with a BMI of 26, however his body doesn't fit what most people think of as "fat". Another example is Arnold Schwarzenegger, who has a BMI of 30.8 and is therefore medically obese. However, his muscle is what attributes to most of his weight and to call him obese would be stupid. In reality, although there are definitely some Americans who are obese, the "stereotypical fat American" is not 100% accurate.
https://www.niddk.nih.gov/health-information/health-statistics/overweight-obesity https://www.medicalnewstoday.com/articles/255712.php
https://www.niddk.nih.gov/health-information/health-statistics/overweight-obesity
https://www.medicalnewstoday.com/articles/255712.php