Sugar tax is the hot topic that has got governments, health campaigners and the food industry talking. As rates of obesity and type 2 diabetes rise in many parts of the world, some say taxes on sugary drinks are a simple way of encouraging healthier choices. But should governments make those kinds of judgements? Katy Watson in Mexico and the US, meets those who think a 'sin tax' is the best way forward for fast food and fizzy drinks. She asks Mexico’s government and drinks industry how their sugar tax has affected sales of the products subject to extra tax. And, she hears from food industry lobbysists and those who think that government has no role to play in our food choices.