Here's one way to live on $1.70 per day if buying in bulk.

    lentil: 180	g
    rice: 180 g
    banana: 120 g
    olive oil: 20 g
    egg: 112 g
    milk: 99 g
    dry roasted peanuts: 50 g

    cost    : $1.70
    calories: 2000
    carbs   : 200 g
    fats    : 56 g
    protein : 175 g

with macronutirent ratio, calories from = fat:protein:carb = 25%:35%:40%