Library.

“In men, having too little body fat causes androgen levels to decrease.”

The evidence does not support the general claim that low body fat in men lowers androgens. High-quality studies more consistently show the opposite pattern: higher body fat is associated with lower testosterone, and reducing excess fat often improves it. A possible exception may exist in extreme leanness with severe energy deficit, but that is narrower and less well supported than the claim states.

“The majority of Americans have a body fat percentage above 20%.”

The claim is well-supported. CDC NHANES data shows median body fat of 28% for men and 41% for women, meaning more than half of both sexes exceed 20%. Since obesity rates have only risen since this data was collected (1999–2004), the claim holds as a conservative estimate. However, 20% body fat is below the healthy range for women (21–33%), so exceeding it is normal and expected for most women — the claim is factually accurate but could mislead readers into thinking this threshold signals poor health for everyone.