Yes, prednisone can (and usually does) make you gain weight like crazy. Such an evil drug, but so effective.
Here are the specific side-effects that can affect your weight:
- Lethargy/fatigue (lower activity level)
- Appetite increase
- Encourages the body to store more fat, especially in face, back of neck, and abdomen
- Muscle and bone disintegration
- Lower hemoglobin count (carries oxygen to muscles)
My laundry list of side-effects from it generally didn't go away completely until about three months after my last dose. But FYI the weight gain with prednisone is typically real fat, not just water-weight like with some drugs, meaning you actually have to work it off by exercising and cutting calories.
However, losing weight and/or gaining muscle on prednisone can be done. For more details, feel free to check out my blog post on it:
"The Dread of Pred".