My gabage disposal used to work very fine, powerful from the loud sound and quick disappear food you can tell. One day the overload switch went off. I noticed there are too much gabage and cleaned them. I pushed in the overload button, but it only work a couple of seconds then went off. Since then, the disposal only work a few seconds each time I push in the overload switch button. Water drain is pretty quick, food is broken to small peices quickly, too. I can not see any overload since that time. Only I can tell the disposal may make too loud noise, but it hard for me to say surely because all disposal make pretty lound noise, I think.
There is probably something like a piece of bone or other material stuck between the rotating plate the the inside edge of the chamber. It is not tight enough to stop the disposer and kick it off, but it is just tight enough to slow it down and create an overload condition.