www.telegraph.co.uk/news/2016/04/24/fattist-discrimination-should-be-outlawed-in-the-workplace-says/
Just read this article and it says it is not illegal to discriminate against overweight people.
Yet fat people are protected only if they can prove they are also disabled
from the article. So it is seems to be ok to discriminate against someone who is fat but not if they are fat and disabled? 
This is worrying though but a separate issue from the same article
New forecasts show that obesity will soon be more common than being a normal weight.The figures from Cancer Research UK show on current trends, almost three in four adults will be overweight or obese by 2035.