The problem here - and The Sun is a gleeful perpetrator of it - is society's negative attitude towards obesity.
Culturally, as a society, we have always linked obesity with laziness and feckless disregard for health and an absence of self-rspect.
The red tops, with The Sun at their head, love to drop terms like 'gut bucket' and 'lard ass' into their stories where an obese person is involved.
Ideally, we are moving towards a more reasoned and compasionate society where obsese people are no longer figures of fun and/or contempt, but seen as indifiduals with differing reasons for their weight issues, which are more often linked with physical and psychological issues than a simple sense of gluttony.
As others hav pointed out - we cannot refuse to treat people based on arbitrary opinions based on no evidence, that some people 'deserve' their condition, what ever that may be. I would hope, as i say, that we have a large degree of compassion than that, because that thinking is the thin end of a very nasty wedge, and the thick end is a seriously unpleasant place to contemplate - no treatment for soldiers - they didn't have to join the army / no treatment for problem pregnancies - women don't have to have children ... the list could go on - but hopefully it won't.