New research seems to prove that it does.
How would a virus like Ad-36 cause fat? Atkinson explains, “There are three ways that we think Ad-36 makes people fatter:
(1) It increases the uptake of glucose from the blood and converts it to fat; (2) it increases the creation of fat molecules through fatty acid synthase, an enzyme that creates fat; and (3) it enables the creation of more fat cells to hold all the fat by committing stem cells, which can turn into either bone or fat, into fat. So the fat cells that exist are getting bigger, and the body is creating more of them.”
More at Wired.
