You are what you eat, there is no denying it. Just as those that grow up on junk food, will probably turn into fat adults. Those that grow up hungry will never reach the size they would have with adequate nutrition.
In fact nutrition probably plays a bigger part than genetics in how we develop.
The wild horses are a good example of this. There genetic pool comes from cavalry horses and farm mounts let loose and allowed to breed in the moutains on the central plateau...yet the horses there today are not horses, but generally ponies. Small around 13hh hands upwards. A combination of lack of food and nutrition, large numbers of horses and breeding young, probably combined to mean that these horse never developed to their full potential, but stated relatively stunted due to their poor diet...
Here the proof
Matai the stallion came back to my lace for the week, and the yearling Sonny who's arrived in his mothers belly form the same muster, recognized his old friend immediately and ran up to him showing the same submissive attitude he exhibited as a weanlings, they both fell straight back into their roles as playmates, and herd stallion and follower.one thing has changed though.... The yearlong towers over the 5 year old ex wild stallion..coming from the same genetic pool,the only thing that can contribute to one looking like a baby war horse and the other being pony sized is that sonny grew up with access to food, and adequate nutrition and his mother could provide Jon with obscene amounts of milk as she wasn't struggling to survive herself..
Check put the proof for yourself.
Ps click the photos to see the whole horse for some reason blogger sometimes crops my images...