Many prepared and take‐away foods contain high levels of ‘unhealthy’ nutrients such as salt, trans and saturated fats and sugar. As diets have developed to include higher proportions of these products, consumers intakes have grown beyond World Health Organisation recommended maximum levels. Countries have responded by regulatory action (Denmark’s banning of trans fats) or collaborative (voluntary) measures with industry. This paper presents findings from case study research in Denmark, the UK, Italy and Poland and at the EU level to address the research questions: Have reformulation actions been effective and cost‐effective? Is collaborative action between government and industry more likely to be effective than industry acting alone? Are there circumstances under which legislation is preferable to voluntary action? Are there benefits to European as opposed to separate Member State action? What are the implications for competition? We find that voluntary reformulation has worked with respect to trans fats and salt. In the UK and at the EU level, firms have made commitments and these have been monitored and acted upon with substantial reductions in levels of salt and trans fats in their products. Manufacturers and retailers (in collaboration with their own‐label suppliers) have done this largely for reasons of corporate social responsibility—it is good for their image to be seen to be conforming and it means they can’t (so easily) be held up by NGOs and the media as behaving irresponsibly. However, despite an impressive rate at which firms have signed up to make commitments to salt reduction, in the UK average intake has fallen by only around 10% to 8.6g, still far in excess of the 6g target. Also not known is the extent to which the voluntary approach leaves high levels of harmful nutrients in foods produced by some companies, perhaps targeted to specific markets. Consumer groups have argued that high levels of trans fats are present in the UK in low quality foods targeted at poor consumers and In Poland it is claimed some foods have 10‐12% trans fats and population intake levels are among the highest in Europe. NGOs and some policy makers believe mandatory standards are the best way to make sure all food is ‘good’ food. Whether it is possible to devise a system that maintains the benefits of the voluntary system but creates a safety net to ensure against any foods containing too high levels of salt and trans fat and saturated fat deserves further exploration. If so, this would probably need to be undertaken at the European rather than Member State level to avoid contravening EU food law. SMEs may need assistance to meet the technological challenges of reformulation. They do this at present through links to research associations and retailers, but such linkages are not well developed for firms in all Member States.