More than one million children are at risk of severe malnutrition in the Sahel region of West Africa, according to two leading charities.
World Vision and Save the Children say that millions of families are suffering in what is effectively a large-scale nutrition crisis.
They say the main reason is not drought or food deficit, but a lack of protection against shock price rises.
The charities want more investment to protect against food insecurity.
Even in what is considered a normal year, the deaths of 200,000 children can be directly linked to malnutrition, they say.
The Sahel region is an impoverished area that includes Mauritania, Mali, Niger, Burkina Faso, Senegal and Chad.
More than 18 million people in the region are currently affected by hunger, the charities say.
World Vision's emergencies director Paul Sitnam said: "The poorest of the poor people... have virtually no access to any food that is available on the market because of their chronic poverty."
He said the problem would not be solved by simply handing out food, and that the international community needed to help the affected areas build up resilience against "shocks".
"It's also ensuring that there's family cohesion, assuring that there's education, assuring that there's infrastructure, and that the social safety nets get to take care of children and their families in the times of crisis," he said.
Crop shortages, rising food prices and insecurity in neighbouring countries all contribute to a chronic crisis, Save The Children says.
In January, Oxfam and Save the Children said thousands of people in East Africa died needlessly from famine last year because the international community failed to heed early warnings.
The organisation's chief executive, Justin Forsyth, is urging talks at a "hunger summit", due to take place at the end of the London Olympics.
World leaders, business figures, non-government organisations and development campaigners are due to attend talks on the last day of the Games.