In a special vegan edition, meat-loving and meat-rearing Jimmy Doherty attempts to go vegan for a week in the US. While he's there, he sees if there's a solution to carbon emissions from belching cows, and samples the latest fake meats on offer, including chicken nuggets grown in a lab. Matt Tebbutt sets out to discover why some vegan products are more expensive than their meaty equivalents, Dr Helen Lawal asks if it's safe to raise children as vegan, and Kate Quilton delves into the surprisingly secret world of the vegan cheese melt.