The World Health Organization cites malnutrition as the greatest single threat to The world's public health. Improving nutrition is widely regarded as the most effective form of aid. Nutrition-specific interventions, which address the immediate causes of undernutrition, have been proven to deliver among the best value for money of all development interventions. Emergency measures include providing deficient micronutrients through fortified sachet powders or directly through supplements.
WHO, UNICEF, and the UN World Food Program recommend community management of severe acute malnutrition with ready-to-use therapeutic foods, which have been shown to cause weight gain in emergency settings.
Long term measures include fostering nutritionally dense agriculture by increasing yields, while making sure negative consequences affecting yields in the future are minimized. (source: Wiki)