A daily serving of nuts, legumes or tofu, which adds protein to the diet and might help protect against diabetes and heart disease. At least one serving of fish per week, which provides fatty acids that are good for the brain and body.

Would you add a few more vegetables and whole grains to your diet in return for a healthy old age? A new study has broken down in detail the food groups that increase the likelihood of healthy aging – and identified the best diet overall.