If you get a chance to watch this (1.5hrs), this is a very good lecture on why sugar is one of the greatest threats we face today. It's not a new argument. Most people know about this, but (speaking from experience) complacency is a bugger and it's so easy to shelve the sugar-is-bad thing and just blindly consume what's 'convenient' and 'easy' in favour of saving time or whatever.
With more and more of the food made available to us being sweetened and cheapened to keep us hooked, we're really up against it.
Some will argue (mostly Food Corp giants) that there is no scientific proof. This is true, because to get the data necessary to scientifically prove, without doubt, that sugar is bad, it will involve largely unethical trials spanning decades and decades. However, this lecture lays down a lot of sound research data that clearly infers sugar's role in causing nearly all of our health problems (particularly obesity), worldwide.
It's not to be sniffed at, and something I know I will be taking more seriously from now on.
(via https://www.youtube.com/watch?v=ceFyF9px20Y)