That's exactly what happened in Great Britain up until the Great War. There were some fascinating (though not very scientific) studies on nutrition in early years and its affect on intelligence, vigor, and survival. Children of the very poor (those who lived on around a pound a week) were smaller, died in far larger numbers, and were overall less vigorous and less intelligence due to reduced nutrition in early and middle childhood. Those children in the study group were given milk and in some cases other nutritious foods, which largely eliminated their deficits and increased risks. (Substandard housing, especially damp and the lack of fresh air, still affected them.)
Note however that this is not a movement of conservatives asking for the poor to be put on $1.37 per day, as your last line implies. Rather this is one (probably conservative) guy who is saying he has experienced it being done successfully, at one time in the not too distant past. Likewise, I don't think you would argue that we are anywhere near those levels (either early 1900s England or $1.37 per day per head) in today's welfare and food stamp culture.