I am overweight, and I have problems with some of the stories in chapter 4 of LICTM. I'm not saying that they're rude or biased, but I prefer not to use them. Instead of talking about training and losing weight, I go in a different direction: what happens if you start obsessing about your weight.
The vocab was as follows: sube de peso, baja de peso, por horas seguidas. Here is the written story (sorry--I don't remember the oral story or PQA.