On this World Food Day more than one billion people are suffering from malnutrition and hunger, an increase of 100 million in just over a year. Consensus, international leadership and urgent action are needed to help end this global travesty.
At the recent G8 summit in Italy leaders committed that food security, nutrition and sustainable agriculture should be prioritized on the global agenda. Lack of access to food in some parts of the world has triggered other threats, including conflict and environmental degradation, undermining the health and wellbeing of children. 
In my travels around the world, I have seen the heartache and pain in the eyes of parents who have lost a child and communities devastated because crops are scarce and disaster, conflict and climate change are impacting livelihoods. This was abundantly clear on a recent visit to the Democratic Republic of the Congo, where attacks by soldiers on villages -- raping and pillaging -- has left destruction and fear, destroying infrastructure, crops and water supplies.
On average, in Africa 40 per cent of children under five years old are stunted which is an indication of chronic under-nutrition. Stunting is high throughout Africa and Asia and among marginalized people throughout the world.
Children who are chronically undernourished before their second birthday are likely to have diminished cognitive and physical development for the rest of their lives. The burden these children carry and the disadvantages they face are not immediately apparent. Children who are stunted are short for their age, but if you saw them and didn't know how old they were, you might assume they were well.
Under-nutrition is an underlying cause of child mortality -- it moves silently and stealthily, inhibiting children's growth and pushing them closer towards death when the state of their health is already precarious. If a child suffers diarrhea from lack of clean water, it will drain nutrients from his or her body. Children who are weakened by nutritional deficiencies cannot stave off illness for long, and the frequent bouts of illness they experience make them even weaker. More than a third of the children who died from pneumonia, diarrhea and other illnesses could have survived if they had not been undernourished.
The health of the child is inextricably linked to the health of the mother. Maternal under-nutrition affects women's chances of surviving pregnancy. Women who were stunted as girls, whose nutritional status was poor when they conceived or who didn't gain enough weight during pregnancy may deliver babies with low birth weight; these infants in turn may never recoup from their early disadvantage. Like other undernourished children, they may be susceptible to infectious disease and death, and as adults they may face a higher risk of chronic illness such as heart disease and diabetes. 
Under-nutrition diminishes the ability of children to learn and earn throughout their lives. Nutritional deprivation leaves children tired and weak, and lowers their IQs, so they perform poorly in school. As adults they are less productive and earn less than their healthy peers. Thus, the cycle of under-nutrition and poverty repeats itself, generation after generation.
It is critical now, more than ever, that the most vulnerable nations, along with international partners, invest wisely in nutrition interventions, which are demonstrated to be among the best investments in development that countries can make. The period from the mother's pregnancy through the first two years of the child's life provides a crucial window of opportunity in which nutrition interventions can be effectively delivered with long-term returns over lifetimes.
While on this World Food Day more people are suffering from hunger and malnutrition, there must be a renewed commitment to save lives.
The world must seriously address the impacts of climate change, conflict and natural disasters on water availability, crops, and food supplies, particularly in the most vulnerable regions of the world. By doing so we can make significant strides to meet and exceed the Millennium Development Goals by 2015.
Ann Veneman is the Executive Director of UNICEF. World Food Day is October 16th, 2009. To learn more about UNICEF programs and World Food Day, visit www.unicef.org.