Business can do good - it is time for us to step up Many carry these burdens through into later life. More than 170m children end up stunted (97pc of them in the developing world), with all the tragic implications for reproductive, health and brain development. As they get older, many of these children are more susceptible to premature death from non-communicable diseases. The challenges are not confined to the developing world. Poor nutrition - especially among children - is growing in Europe and North America. I was told during a visit to a Food Bank in Washington DC recently that one in five of the city's children are undernourished. At the same time, the US and Europe are battling against an ever rising tide of obesity. Most worryingly, the obesity epidemic is now spreading to poorer countries, such as Guatemala, where the obesity rate has quadrupled over the past 30 years. Addressing the nutritional challenge is not an easy one, and nor is it one for the public or private sectors alone. As David Cameron emphasised when he hosted the Olympic Hunger Event in London earlier this year, governments and business have a shared responsibility to tackle the issue. I agree. Fortunately, many responsible businesses are taking up the challenge, whether in developing affordable and nutritious products, investing in scientific and technological breakthroughs or partnering with others on educational programmes. PepsiCo, for example, is spearheading a campaign to reduce iron deficiency in India, including through the use of fortified snacks aimed at a particularly vulnerable group, adolescent girls. SM's fortified NutriRice product is helping to improve the nutritional value of rice, a mainstay of diets across large parts of Asia and Africa. Kraft's low-price energy biscuit, Biskuat, containing extra vitamins and minerals, is selling well in Indonesia. And a Britannia Food nutritional campaign targeted at villages in southern India is leading to improvements in the height and weight of children. At Unilever, we know only too well the impact that initiatives like these can have. Indeed, a commitment to improve basic nutrition goes back to the origins of the company, whose Dutch forefathers developed iconic margarine brands such as Blue Band and Stork as affordable alternatives to butter. These brands, and others such as Flora and Rama, are fortified with vitamins and contain healthy essential fats for a balanced diet. They are still loved and enjoyed by millions of people every day. So are our fortified Knorr savoury products, sold around the world, and our soy-based drinks, popular in Latin America. However, while many businesses are taking up the call, we still lack the critical mass needed to make a decisive breakthrough. That is why I was delighted to support the launch in London recently of the Scaling up Nutrition (SUN) Business Network. The United Nations-backed SUN movement has already proved highly effective in bringing together - under the energetic leadership of David Nabarro - many of the key actors involved. By extending the role of business we have a chance to really move the needle. The moral argument should be enough for companies to want to get involved. It cannot be right that millions of lives are blighted or cut short when we have it within our power to make a difference. Business cannot be a mere bystander to a system that gives us life in the first place. But there is also a compelling business and economic case. We know that people are increasingly drawn to those companies that are committed to find solutions to today's social and environmental challenges. And, as leading economists at this year's Copenhagen Consensus confirmed, combating malnutrition represents the best development investment. Every $1 spent combating hunger and malnutrition in the developing world unlocks $30 of savings in reduced public health costs and increased economic productivity. In recent years, the issue of food security has found its way on to the agendas of both the G8 and the G20 and we need to keep it there. An increasing number of world leaders realise that we have to act now if we are to feed a rapidly growing population while providing sustainable and productive employment to tens of millions of smallhold farmers around the world. Business has played an important role in those discussions and in advancing recommendations. It's now time for political and business leaders to come together in the same way to tackle malnutrition. SUN can be a true vehicle for change. Twenty eight years ago we rallied to a call to feed the world. Despite progress, there is much still to do. And by addressing the nutritional - and not just the calorific - challenge, we have the opportunity not only to extend lives, but to improve the quality of those lives at the same time. Business can do more. For too long it has trailed behind when it comes to nutrition. Some, like Unilever, are looking to be trail blazers. It's time for others to join. It's time to end the suffering of malnutrition. Paul Polman is chief executive of Unilever