The United Nations' goal to eradicate hunger by 2030 is a long way off. After a decade of progress, the number of people starving has risen over the last three years, the UN said in its latest report on food security: 820 million people suffer from chronic hunger, including 149 million children under the age of five who are stunted due to lack of food.

There are 96 million people for whom "we must provide food — or access to food — so people don't die," said Cindy Holleman, one of the main authors of the UN report.

The authors estimate that around two billion people worldwide do not have sufficient access to clean and nutritious food. In every continent, a greater proportion of women struggle with food insecurity than men. Eight percent of the population in Europe and North America are hit by food insecurity.

Most of the world's chronic hungry, who don't have enough food — healthy or not — live in Asia (500 million), with about half as many in Africa (260 million), particularly sub-Saharan Africa.

Watch video 01:13 Sustainable Development Goals: Zero Hunger

"Inequalities are actually rising in more than half the countries in the world," said Holleman. "Hunger is worse when inequality is high."

According to the recently published "World Wealth Report", there are about 18 million people in the world who own at least one million dollars.

Where income and arable land are unequally distributed, famines can even occur in middle income countries such as Nigeria and Iraq.

Not everybody who suffers from malnutrition is thin, says Holleman. "We're starting to see now that we have a greater link between food insecurity and overweight and obesity," said Holleman. Two billion people are estimated to be overweight. Unhealthy food is usually cheaper, she said.

The report identifies three main reasons for lack of access to food: conflict, climate change and a weak economy.

Fighting worsens hunger

From looting by government soldiers to militias in South Sudan or the Democratic Republic of Congo, war and armed conflict are the main causes of hunger.

Since the beginning of the war in Yemen in 2015 around 3.6 million people have been displaced.

"Nearly four years of conflict and severe economic decline are driving the country to the brink of famine and exacerbating needs in all sectors," says Federica D'Andreagovanni, who works for the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) in Yemen. In war zones, the supply of the most basic goods collapses as it becomes harder to cultivate fields or run shops. "Humanitarian conditions in Yemen are worsening at a nearly unprecedented rate."

Zimbabwe's economic crisis leaves citizens struggling for basic goods

Import and export

Zimbabwe is experiencing a severe economic crisis as its currency depreciates: goods becoming more expensive, salaries no longer being paid, imports drying up. In front of petrol stations, cars queue for hours.

"Fuel remains difficult to access," said Nathan Hayes of the Economist Intelligence Unit analysis agency. "There are major shortages of bread, as domestic maize production has been decimated and the country cannot afford to pay for imports."

Around two million people in Zimbabwe do not have sufficient access to food.

"The depreciation of the currency… affects prices, which can affect people's access to food, income and employment," Holleman told DW. "And Zimbabwe is an extreme case."

In Nigeria, five million people lack enough nutritious food. The oil-dependent export economy has suffered from low oil prices. Here, too, inflation has pushed food prices higher.

The report found 65 of the 77 countries where slower economic growth has led to food shortages are dependent on exports — often oil, minerals — and imports. Countries need to diversify and transform their economies, said Holleman, so that they become less dependent on imports and exports, and to make "rural areas and urban economies provide more sustainable alternatives to livelihoods".

Droughts are becoming more frequent in Kenya

Climate change and food security

In Zimbabwe, the economy will shrink due to the devastating destruction of the drought and Cyclone Idai, said Hayes. Weather extremes caused by climate change have already hit harvests and food supplies around the world.

"The long rain season is normally from March till end of May," said Peter Abiya Ochola of the National Drought Management Authority in Kenya. "This year, for example we had very poor rain season. It started late in April and lasted just three weeks with some little rain showers." Drought years are becoming more common in Kenya. Whereas droughts used to occur every five years, said Ochola, today they occur every one to two years.

"The impact on food security is bad," said Ochola, who estimates 1.5 million people in Kenya are affected by drought this year — particularly farmers whose fields or livestock depend on rain.

To eradicate hunger, the United Nations report calls for international agreements that create peace and sustainable economic transformation so that developing countries can better prepare themselves for the causes of hunger.