Are You Too Heavy For Your Horse?

We have seen temperatures in the 50's for the past two days. It gives me a bit of spring fever when this happens (and makes it all the more disappointing when the cold weather comes crashing in again).

I wanted to lose weight this month to lighten up in the saddle. I haven't lost enough yet. I've lost four pounds so far without diet pills. Only 21 more pounds to go!

I am not grossly overweight (almost borderline I think) and certainly not too heavy for my part draft horse but I feel like I need to lose some weight. Seeing pictures of myself in the saddle makes me cringe.

I have seen people on horses who appeared to heavy for the horse and I felt bad for the horse. I want to make sure I do not become one of those people. How do you determine what the proper weight limit is for a horse?