The person can barely be identified. So unlikely this directly shames or affects him.

I’m worried about overweight kids receiving such jokes in their school-chatgroups, not the guy in person.

Now things out of a person’s control (skin color, height, physical abnormalities, etc) should be off the table unless the individual explicitly states otherwise.

There is a significant relationship between the political/economic system a person is in and the prevalence of obesity in a society. What system someone is born into is beyond the control of the individual.