The medical term for skinny fat is MONW, which stands for metabolically obese, normal weight, People who are MONW may look healthy but are at risk for conditions like diabetes. They have a normal BMI and weight but low muscle mass. Skinny fat people tend to have a type of fat called visceral fat. Visceral fat grows around your organs instead of under your skin, so it isn’t visible. If you have visceral fat, you may not look overweight, but you may have as much fat as someone who looks heavier.

Thin at the waist doesnt always mean thin in the pants..

Thin in the heart doesn’t always mean thin in talent.

Here are some example illustrations of individuals who are MONW. As you can see they have very low muscle mass. They may not overeat, but they have very sedentary lifestyles. They also don't lift weights, at least not seriously.