Nuts are a rich source of fibre and polyphenols. They are also very high in fats and calories, but studies have shown that eating these bite-sized snacks won’t add to your waistline. These nutrient powerhouses could also help slow-down the ageing process. Research has found that walnut eaters live, on average, over a year longer than those who don’t. What’s more, adding nuts to your diet can help your brain! Michael Mosley is joined by Dr Sze-Yen Tan from Deakin University in Australia who reveals how eating nuts can benefit the brain, and why eating moderate amounts of nuts won’t add to your waistline. A recent study of his found that people who ate nuts performed better in cognitive tests and had improved short-term memory. Meanwhile, our volunteer Emma swaps out her usual snack for a handful of mixed nuts!