"surplus fat" VS "surplus of fat"

Consider this sentence :"Obesity is a surplus fat deposited in the adipose tissues" I am wondering if " surplus fat" is correct or "surplus of fat" . "surplus" can be noun as well as adj so I think both styles are correct. Am I in a right track ?

Solution 1:

As stated above I think either "a surplus of fat" or "surplus fat" (no "a") is fine, grammatically.

However, I'm not sure it's correct, medically. Obesity is a property of the person, it is not the fat itself. Obesity is not the fat, it's the person with the fat. So, although this may be more verbose, I might say, "A person suffering with obesity has a surplus of fat stored in adipose tissue." Or something - but, I'm not a doctor.