In 2023, the UK government announced a Major Conditions Strategy, publishing ‘The case for change and our strategic framework’, which set out the focus on cancers, diabetes, dementia, mental ill health, musculoskeletal disorders, CVD and chronic respiratory diseases. Together, these conditions account for 60% of total disability-adjusted life years lost to early death or ill health in England, and one in four adults has at least two (multimorbidity). This review considers some of the key dietary risks for these major conditions and population policies that may improve diets and reduce risks. UK Government dietary recommendations, based on independent risk assessment and advice from the Scientific Advisory Committee on Nutrition, are encapsulated in the national food model, the Eatwell Guide. Based on key sources of dietary data – chiefly consumption data from the National Diet and Nutrition Survey and consumer purchase data from Kantar – most people do not meet dietary recommendations. This review considers how science and evidence inform health improvement policy. This includes policies that encourage healthier food choices, such as labelling and public procurement standards to those that minimise the impact of the less healthy choice such as sugar and salt reduction and reformulation. The review also considers nutritional approaches to managing some non-communicable diseases. Given the role nutrition and excess weight play in the onset, prognosis and quality of life for those living with one or more of the major conditions, there are huge potential gains from even small dietary improvements across population groups.