04/08/2016 07:58 BST | Updated 04/08/2017 06:12 BST

129million Children Will Still Find Their Physical and Mental Development Stunted By Malnutrition in 2030

There is genuine optimism that child malnutrition can be eradicated within a generation. Rates of chronic child malnutrition have plummeted by a third since 1990, leading to increasingly bold commitments in achieving zero global hunger. Just last year, in signing the Sustainable Development Goals, leaders from countries around the world set themselves a deadline of 2030 to end all forms of malnutrition.

However, as governments gather at the Nutrition for Growth Initiative in Rio this week to discuss investments needed to improve global nutrition, Save the Children's new research,

Unequal Portions, sounds a clear warning. Our evidence shows that by the 2030 deadline, on current progress, 129 million children will still have their physical and mental development irreversibly damaged by a lack of nutrition. Many of those most in need of help are the hardest to reach, and much bolder action is needed to reach them.

Unequal progress is leaving excluded groups behind

Millions of children miss out on adequate nutrition because of who they are and where they live. They are the forgotten children; children discriminated against because of their gender or ethnicity, because they have a disability, because they have been forced from their home, or because of their family is desperately poor.

The extent of nutrition inequalities is staggering. Looking across developing countries, a child born in Papua New Guinea or Madagascar has a 1-in-2 chance of experiencing irreversible malnutrition - or stunting - compared with a 1-in-5 chance for a child in Peru.

Just as important is where a child is born within a country. In a third of our 56-country sample, we found that children living in the worst-performing regions are more than three times more likely to be malnourished than those living in the best regions. In Peru, for example, children in Huancavelica region are 16 times more likely to be stunted than children from the region of Tacna.

Overall, inequalities in malnutrition are widening between different regions within countries, between the richest and the poorest, and between rural and urban areas. What's more, discrimination and exclusion are helping to create and perpetuate these inequalities.

In short, progress to date has simply not been fast enough or inclusive enough.

What can we do to reach every last child?

Our report recommends social protection, education and universal health coverage as policies that, when adopted correctly, can reduce these deadly child nutrition disparities.

On Thursday August 4th, on the eve of the 2016 Olympics opening ceremony in Rio - government leaders from Brazil, Japan and the United Kingdom (the current, future and previous hosts of the Olympic Games) are gathering to launch the next phase of Nutrition for Growth. It's vital that they demonstrate the high level of ambition that's needed to enshrine the right to food and nutrition the world over.

In 2013, at the Nutrition for Growth summit in London, more than 100 partners - including governments, businesses and charities - pledged over $23 billion to tackle malnutrition. This week, Save the Children is joining other charities, governments, the United Nations and businesses to call for a new pledging summit to take place in 2017. Together we're pushing for this latest phase of Nutrition for Growth to help deliver the investments needed to end malnutrition for every last child, no matter who they are or where they live.

Jamie Oliver's endorsement of our Unequal Portions report:

Good nutrition is every child's human right. Alarmingly, [Save the Children's] report shows that many kids are not getting the correct nutrition they need in order to grow and thrive, and certain groups of children are being left behind because of who and where they are. For me, this is unacceptable. Who you are, what sex you are, and where you are born should not impact on your right to good nutrition. As a campaigner for better food and nutrition, a chef and ultimately as a father, I want the world to be a place where all children have access to good, nutritious food and food education. I want children everywhere to be armed with the knowledge to ensure they can make the best choices from what's available to them. That's why I'm proud to support Save the Children's new nutrition report and their Every Last Child campaign. The change we need for a healthier and happier world is more urgent than ever, and that change must reach every child. The health of future generations is in our hands."