If you have the time Gary Taubes' 'The Diet Delusion' very comprehensively puts the case for refined carbs, sugar and wheat being hugely responsible for western diseases and diet problems, especially diabetes. He is a medical investigative journalist, with no particular axe to grind, and has looked at massive amounts of research on this with a very balanced approach.
Going back a bit further, other interesting reading :
'Pure, White and Deadly' by John Yudkin, concerned about sugars as disease forming agents
'Not all in the mind' Richard Mackarness. about the effect of wheat on mental and physical health
A Royal Navy surgeon , T.L.Cleave, in 'The Saccharine disease' , identified what he called The Twenty Year rule regarding western type diseases appearing in 'non-developed' civilisations. He identified rapid increases in cancers, thromboses and other degenerative illnesses in civilisations within twenty years after the introduction of refined flour and sugar into their diet.
Many people can eat refined carbs without problem, but many others suffer quite badly because of them, me included.Asthma much worse when over eating sugars and wheat., dairy not a problem for me.