A staggering 2 billion people get so little essential vitamins and minerals from the foods they eat that they remain undernourished, according to the 2014 Global Hunger Index (GHI) being released today by the International Food Policy Research Institute, Welthungerhilfe, and Concern Worldwide.

This "hidden hunger" - the focus of the report's main essay - is often hard to detect, but is potentially devastating. Hidden hunger weakens the immune system, stunts physical and intellectual growth, and can lead to death. It wreaks economic havoc as well, locking countries into cycles of poor nutrition, lost productivity, poverty, and reduced economic growth.

The 2014 GHI examines levels of hunger in 120 developing countries and countries in transition and scores them based on three equally weighted indicators: the proportion of people who are undernourished, the proportion of children under five who are underweight, and the mortality rate of children under five.

While great strides have been made to feed the world, 805 million people are still chronically undernourished because they don't get enough to eat. Yet even those who eat enough calories can suffer from hidden hunger, a critical aspect of hunger and nutrition that is often overlooked. To combat it, we need to enable the production of diverse crops and ensure the availability nutrient-rich foods, including fruits and vegetables.

"Particularly in countries facing a high burden of malnutrition, hidden hunger goes hand in hand with other forms of malnutrition and cannot be addressed in isolation," said Welthungerhilfe president Bärbel Dieckmann. "In the long-term, people cannot break out of the vicious cycle of poverty and malnutrition without being granted the basic right to nutritious food."

The good news in this year's GHI is that the number of people going hungry has steadily decreased in most developing countries. Since 1990, hunger in the developing world has fallen by 39 percent, and 26 countries have reduced their scores by 50 percent or more. Angola, Bangladesh, Cambodia, Chad, Ghana, Malawi, Niger, Rwanda, Thailand, and Vietnam have seen the greatest improvements in their scores between the 1990 GHI and the 2014 GHI. The bad news is that levels of hunger are still "alarming" in 14 countries, and "extremely alarming" in two, Burundi and Eritrea.

This year's GHI includes provisional data from India on underweight in children under five, for the first time in eight years. Improvements in this index indicator show the prevalence of underweight in children fell by almost 13 percent between 2005-2006 and 2013-2014, contributing to India's movement in the Index from the "alarming" category to the "serious." Due to its sheer size, gains in India helped South Asia improve its 2014 GHI score: Levels of hunger in the region have fallen by 41 percent since 1990.

"We are excited to see that there are improvements in India and also globally," said Shenggen Fan, IFPRI's director general. "The GHI shows that hunger has been decreasing since 1990, but there is much more to be done to address hunger-including hidden hunger-to ensure food and nutrition security for the most vulnerable."

Hidden hunger affects not only the well-being of the individual. It also carries economic costs, cutting gross domestic product in many developing countries. Yet the benefits of action can be great: Research on the effects of salt iodization suggests that every dollar invested in iodization generates up to $81 in benefits.

"The great news is that we have clear evidence proving that investing in nutrition is one of the smartest development investments we can make," said Dominic MacSorley, CEO of Concern Worldwide. "What is needed now is more practical action on the ground, such as our RAIN project in Zambia included in this year's GHI report, and more political action at the international level to end all forms of malnutrition."

Preventing and treating hidden hunger requires action at all levels. The global community must ensure that the post-2015 framework includes a universal goal to end hunger and malnutrition in all its forms and clear mechanisms to ensure accountability.