Counting the cost of the global obesity epidemic. More than a billion people across the world are obese with warnings the disease is on track to drain trillions of dollars from the global economy. The head of the World Obesity Federation explains the size of the problem. And the Chief Medical Officer from WeightWatchers discusses solutions and the latest weight-loss drugs. Plus, providing the nuts and bolts to power the AI revolution, we hear from the boss of Cisco Systems, Chuck Robbins, on the latest moves in the world of machine learning.