Though close to a billion people remain undernourished worldwide, one in three U.S. children are overweight – a problem that First Lady Michelle Obama has made her priority over the first two years of her husband’s administration.

This rate of overweight or obese U.S. children has tripled in the past 30 years and is now becoming a broader problem for wealthy countries more generally, officials say.

Health and obesity issues, says Sam Kass, assistant chef at the White House and senior policy adviser for the Obama’s Healthy Food Initiatives, are now an international challenge.

“It’s not just a challenge for the United States, although we’ve been dealing with it for quite some time. But you see rates going up all over the world and that’s going to be an increasing challenge that we’re going to have to come together to work on – to try to make sure that all of the world’s citizens are getting the food that they need to nourish themselves,” he told a group of reporters Tuesday.

Obesity in children can lead to emotional as well as dangerous physical conditions including diabetes, heart disease, high blood pressure or even cancer. And, for someone used to the amenities of modern life, obesity can have multiple causes – lack of exercise, too many high-sugar or high-salt snacks, unhealthy school lunches, etc.

With that in mind, Obama’s approach has been to take on the problem from multiple angles.

In February, her office launched a campaign called Let’s Move to facilitate partnerships between U.S. states, business and non-profit organisations toward the goal of solving the challenge of childhood obesity within a generation.