Sugar is pro-inflammatory, and so is omega-6 fatty acids, the consumption of both of which has increased massively within the last 60-70 years. Omega-6 fats have gone from less than 5% of human diet to up to 30% today, thanks to the commercial success of 'vegetable' oils. These two alone probably represent the most conspicuous diet changes that have happened in our societies in recent history and should be obvious suspects when looking at disease factors, imho.