For those of you who don't know me outside of the interweb, I'm tall.  Above average for sure.  In my teen years I briefly had the nickname "Freaky Tall".  Although I have tall on both sides of my family it seems that a lot of my peers are also taller then their parents, and many are taller than their grandparents (even taking pre-old age shrinkage into account). 

Last year I read a paper which pointed out how the current generation of young people in Asia are much taller then the generation that proceeded them.  This article makes the argument that the generation that is taller was brought up with better nutrition than their parents.  As these countries became more industrialized their citizens got more access to and more rounded diet, and the extra calories and nutrients they received in their peak growing years made them taller then the generation before them. 

Nature is a key part of this; more nutrients = more growth.   But what about nurture (nature's counterpart in the procreation process).  The want to give your children better then you had as a child is one of the ways in which you nurture that child.  What better is to the individual is defined by the culture that person associates with.    An example of this is  people who choose to feed their children a vegetarian or vegan diet, their decision is one that they've arrived at because of their culture (religious in some parts of the world,  perceived health reasons in another and for ethical reason in others).   It is their culture that is informing their choices, not nature.  North America's childhood obesity rates, are part of these changes as well.  Parents are not deliberately hurting their children by overfeeding they are trying to make their children happy.   It's just that the foods that their children want are deviously unhealthy (although that could just be my naive opinion not being a parent myself.) These changes in people's physical appearance have to do with what they eat and these changes are drastic because the changes in how we eat are drastic.

With changes in agriculture and food cultures happening so rapidly we are seeing the affects the youngest generations more immediately, not spread out over many generations.  In the case of people being taller then their parents it's a neutral thing, but when it comes to childhood diabetes and obesity rising at such an alarming rate it becomes a negative thing.

The core that unites all of these issues is parents wanting to give their children something better.  More nutritious food is better, more food is better, an alternative diet is better.  What we are beginning to see is the long term effect of better.