More than 170 governments have pledged to do more to prevent malnutrition around the globe, adopting voluntary guidelines to promote healthy diets and reduce levels of obesity at the start of a three-day UN summit in Rome.
Currently, some two billion people - one-third of the world's population - suffer from nutritional deficiencies, including vitamin A, iodine, iron and zinc.
Such deficiencies caused 45% of all child deaths in 2013. At the same time, some 42 million children under the age of five are overweight and some 500 million adults were obese in 2010, UN figures show.
The guidelines to tackle malnutrition note that wars, natural disasters and epidemics such as Ebola have devastating effects on healthy diets and called for the safe distribution of food and medical supplies to people in need.
Governments pledged to invest more in nutrition programs, encourage breast-feeding and develop farming policies that promote sustainable, safe and nutritious diets.
The guidelines also call on governments to protect consumers, especially children, from "inappropriate marketing and publicity of food" to reduce growing obesity levels.
They noted that sedentary lifestyles combined with saturated fats and sugar, were responsible for rising rates of obesity and disease - in rich and poor countries alike.
Jose Graziano da Silva, head of the UN Food and Agriculture Organisation, said obesity was not high on the UN's agenda when governments last pledged to fight malnutrition at a UN conference 22 years ago.
But now, "many developing countries, especially middle income countries, are facing the multiple burdens of malnutrition simultaneously: undernourishment, hidden hunger and obesity".
He said ending malnutrition required balancing interests between producers and consumers and required the private sector to work with governments and legislators to promote healthy diet policies.