A question some of our colleagues in New Zealand have raised about the results in this study – why did you not impose some minimum constraints on some of the food items (eg, all above 10 g to increase realism). The answer is that we initially tried this and it resulted in multiple revisions that kept producing small amounts of other foods – so that the principle of “optimisation” started to be defeated. So we ultimately decided to set no minimum food weights and recognise that in the real world many daily ingredients of meals are at very small levels per portion size eg, ingredients in stews, in salads and sandwiches etc.

Further to the issue of the general realism of the diet scenarios in Table 1, it needs to be emphasised that a goal of this work was not to develop “daily diets” that could be prescribed by health authorities. Instead it was to assess the general feasibility of lower-salt diets and to identify the types of foods that could achieve this and perhaps be exempt from food taxes or used more frequently by institutions involved in food preparation.

If health authorities or institutions were to use these results in potential meal design, they could use as a starting point the dietary scenarios which had the best profile in terms of high fruit and vegetable intake ie, the Mediterranean and Asian dietary scenarios.

We could also have noted the issue that a dietary transition from consuming high-salt processed foods to more unprocessed foods has the “cost” of increased food preparation time. This is indeed an important issue and highlights the importance of societal-wide skill development in how to prepare healthy meals quickly, or pre-prepared as multiple portions and then frozen. There is also the idea that it is also possible to have a very healthy lunch that is as simple as a handful of nuts, sunflower seeds and a piece of fruit.

There was fairly extensive coverage in the New Zealand media of this work and it is hoped that this will stimulate further discussion around the pros and cons of voluntary changes by the food industry (which can be very slow but may be more politically acceptable) versus regulating upper limits of salt in processed food or applying junk food taxes.