Throughout each episode there's a shower scene. It is censored.
Occasionally, the gastric bypass patient featured in the episode will have a sad backstory that led to their excessive weight gain, and it sometimes includes child abuse of a sexual nature.
Contestants are sometimes shown naked throughout the show, It's all censored though.
Note: everything that I typed here applies to the entire series, not just Season one. In general, all of the seasons have the same amount of nudity, profanity, intense content, etc.
No sexual content. However, some of the people on the show TALK about sex and sex-related topics.