It's not completely clear from your question whether you want to know if obesity causes illnesses, or you want to know if diet causes illnesses even after controlling for obesity. I'm going to assume you are mainly concerned with whether obesity has a causal relationship to illnesses, or is just correlated with them.
This question has been addressed by the ...
Q: So, is the claim that you should consume sugary drinks with carb-heavy meals to reduce your calorie consumption when compared to diet drinks credible?
In the abstract of the study in Yahoo Style they said: "New research suggests that we might be better off ordering the full-fat version of our favourite drinks to guzzle down post-meal instead." Nobody in ...
The NHS lists a number of causes of acne. All of them are systemic, so they will not affect one part of the face more than any other.
The basic mechanism is:
Acne is caused when tiny holes in the skin, known as hair follicles, become blocked.
This is caused by the over-production of sebum, which is not affected by any of the organs listed.