Hi Suze,
Prednisolone is an oral steriod - a gluccortiod one which means it acts more on reducing inflammation rather than for the body building! So it reduces any swelling and inflammation around joints and injuries. (But in HMS there isn't always inflammation so depends on the injury/problems you have whether it works)
It can cause fluid retention and increased appetite - hence the gaining weight - but this is usually for people on long term courses. If you are on a course for more than 2 weeks then you usually need to cut down the dose slowly (depending on the dose).
It can cause stomach problems (including acid), and if taken long term with people with stomach problems then it is usual to give a stomach protecting drug as well. (H2 antagonist or PPI)
Yes - Easter puts on the kilo's as well. So I have put on all the weight I have lost since the new year in one weekend

Benign Joint Familial Hypermobility Syndrome (BJFHS) - Confirmed Prof Bird April 2008

I am a Pharmacist and I will give my opinion on these boards. However, always ask your own health professionals for your individual circumstance.