That being said would you send your horse to a trainer that is obviously obese? Keep in mind that the average horse should only carry 24% or less of it's own body weight. The great majority of young horses under the age of 4 only weigh about 900 lbs or less. They gain much of their muscle mass and bulk weight after the age of 4 years old. That means that the person doing the first rides should weigh less than 200 lbs with the equipment making up the other 25 lbs to be less than the maximum total weight of 225 lbs.
About 15 years ago I was looking for a trainer for a young mare that I had rescued. She had some serious problems and was not broke. Several trainers were recommended to me so one Saturday I made arraignments to interview them all at their barns. I told them I wanted to see them working with a horse. The first 2 were women and the last 2 were men. Out of the 3 people I saw one of the men was huge. He must have weighed close to 350 lbs and was riding a 3 year old 14 hand horse. I told him that I would get back to him - I never did. I still cringe when I see him riding in my mind.
Today I ran across a rather large trainer while looking at horse websites. He is, in my own opinion is too heavy to be riding the horse that he is pictured on. I have no idea if he is a good, bad or so-so horse trainer but I would not want him on my horses' back.
Here is his photo:

He actually looks lighter than the obese trainer that I met years ago, but still too large in my opinion.