The statement is true; a significant portion of Americans fails to meet the recommended levels of physical activity, according to health reports and guidelines.
The statement that '2/3 of Americans do not meet the recommended levels of exercise' is true. Reports by health authorities like the American Heart Association and the U.S. Department of Health and Human Services (HHS) have highlighted that a large portion of the American population is not achieving the physical activity guidelines.
A 2018 report from the American Heart Association estimates that 8 out of 10 Americans do not meet these guidelines. Moreover, the increasing rates of overweight and obesity in the United States, where over 70 percent of Americans are overweight or obese, further supports the claim that insufficient exercise is a common issue.
So, the prevalence of physical inactivity is a significant health concern in the United States, as the majority of Americans do not follow the recommended levels of moderate to vigorous physical activity.