>The current over-abundance of food is changing the the timing of puberty for example.

Is it food availability, do you have a citation - I hypothesised that this was due to the wash of oestrogen-like chemicals and hormone disruptors in domestic use in the more developed nations.

Edit: an example citation - http://www.telegraph.co.uk/earth/earthcomment/geoffrey-lean/...; other articles note the increase in the use of soya in countless processed foods and the high levels of oestrogenic chemicals it has.