"Being obese and being overweight are not exactly the same thing. An obese person has a large amount of extra body fat, not just a few extra pounds. People who are obese are very overweight and at risk for serious health problems."
One reason obesity is such a threat - is that it often takes a long time for it to come on.
It's so overlooked, because generally, doctor's are not trained to see it when it's staring them in the face or to look for it instead of at the symptoms, and many aren't trained to treat it.
Some of the complications include pre-diabetic symptoms, insulin resistance, metabolic syndrome, immune-system disorders, liver disease.. All begin with obesity.
A recent article in Huffington Post says that 1 out of 2 Americans currently have this "deadly disease" and 90% of them don't know it.
Some of the best advice both to avoid obesity and treat it involve eating moderate portions; eating healthy (especially lots of vegetables) -- avoiding processed foods; handling excessive stress; and getting lots of exercise.