I would assume studies on the long term effects of mistreating newborns are few and far between. Added to the fact that if they arent cared for properly during the first bit they may not get proper nutrition throught childhood so effects could be skewed by later effects as well.
As for lacking nutrition early on i would suspect doctors may pick it up early on based on weighings. All babies lose some weight from their birth weight (fluids as well as a bit of time before mothers milk fully comes in). At 10% loss doctors become concerned, at 20% your likely in a childrens hospital somewhere.
Our child lost a bit over 10% due to low milk supply and was looking fairly gaunt at a couple weeks to a month and was diagnosed with "failure to thrive" which got us some pumped milk from the milk bank. Once sufficient nutrition was sorted she quickly gained back the weight. Since then she has been around 50% weight at dr check ins and is doing great at 1.5years. Stronger and quicker then many other toddlers at the same age.
So from a nutrition standpoint i dont think 2 weeks is going to do any long term damage, i do think you will have a unhappy and hungry baby though as their stomachs are only big enough to hold a few hours worth of food at a time (breastmilk which tjey do process a bit faster then formula). For us at least an unhappy baby would mean we dont sleep since she was in our room.
I realize this wasnt a direct answer to your question, as stated in the beginning i doubt there will be much scientific research that can isolate that specific cause to long term effects.