Last year, the healthy food standard, based in part on a policy proposal by Nesta, was announced as part of the 10 Year Health Plan.

It aims to break us out of policy paralysis. We’ve relied on dietary advice, voluntary initiatives and low-impact regulations to help people lose weight for 30 years and in that same time, obesity rates have doubled. Our willpower hasn’t changed over that time, but our food environment has. The food that’s available, affordable, promoted and marketed to us has become steadily less healthy over time.

The healthy food standard will require food businesses to play their part in improving the food environment by making small changes to how they sell, promote and develop food. This will help to get more healthy food on their shelves and in our diets.

This policy is critical because we’ve reached a point of urgency - today two in three UK adults live with obesity or excess weight, childhood obesity is among the highest in Europe and these conditions cost our economy and NHS billions.

Now it’s six months since the announcement and we’re still waiting for more detail on implementation. Here are six important things to know about the healthy food standard, to ensure it has the biggest impact on health.

The healthy food standard, based in part on Nesta’s proposal for health targets for retailers, will mandate a minimum target for healthy food sales for large food businesses. This will require them to sell healthier food to improve their overall health score, setting a new standard across the sector.

Mandatory data reporting on the healthiness of food sales is a fundamental prerequisite to the setting of any targets and should be fast-tracked as soon as possible across the food sector. However, evidence shows reporting on its own will have minimal effect - it is the setting of mandatory targets that will drive the impact on obesity.

With the policy estimated to reduce obesity by around a fifth, the government must not delay in progressing reporting so that a target can be set.

The nutrient profile model (NPM) can be used to set an ambitious but achievable health target. At Nesta, we recommend implementing a targets-based system around the NPM because businesses are already familiar with it - it underpins existing regulations that define food as high in fat, salt or sugar (HFSS). It can be applied to calculate the health score of a supermarket's average sales. For ease of interpretation, NPM scores can be converted to a 1-100 scale (1 = least healthy, 100 = most healthy).

Using this converted score, we calculated the healthiness of the largest supermarket retailers and modelled what an effective target would be. Our analysis found that setting a target close to the level of the healthiest-performing retailer (an NPM score of 69) would reduce obesity by around a fifth, making this a pragmatic and feasible route for driving down obesity rates.

We welcome the government’s announcement in the 10 Year Health Plan to update the NPM currently used in legislation, but do not see the need for this to delay the implementation of the healthy food standard.

The healthy food standard is designed to be an outcome-based form of regulation. Rather than telling businesses what to do, it tells them where they need to get to - it’s up to them to decide how. They can use whatever tools at their disposal to hit the target, while keeping the cost of a basket of food down.

The changes businesses will need to make are modest, and the tactics are familiar. In supermarkets that might mean putting healthier ready-meals on offer, tweaking the recipes of own-brand sandwiches so they contain slightly less fat or giving more shelf space to cereals that have a bit less sugar.

If these tactics are employed in the retail sector alone, this could lead to people living with excess weight consuming around 80 fewer kcal per day - an important shift that would help over three million people achieve a healthier weight.

At Nesta, a key consideration when designing this policy was to minimise burdens on business. In the case of retailers, our analysis showed it's entirely possible to improve a supermarket's health score without losing income or charging shoppers more.

Retailers possess the data needed to make this work: nutritional information they hold for existing HFSS regulations, and sales data. The main adjustment is linking these datasets and using the NPM to define a health score, rather than a binary ‘HFSS or not’ classification. Beyond data, the tactics retailers would use to make health a greater priority - promotions, product placement, stocking decisions - are all part of their current toolkit and simply need reorienting towards health. This keeps transition costs low relative to operating budgets and annual profits. A mandatory policy also levels the playing field, while voluntary action has previously meant some businesses risk losing competitive advantage by acting alone.

Given obesity is one of the leading causes of ill health in the UK, the real question is not whether to regulate the food sector but how to do it well. Businesses will be best placed to adapt if the government sets out its plans in a timely manner.

Global commodity and supply issues have intensified food inflation in recent years, leaving consumers particularly pinched. We recognise that regulation can sometimes lead businesses to pass on costs to consumers - but an independent economic assessment we commissioned suggests this is unlikely for the healthy food standard.

The assessment found that the cost of implementing the policy is low relative to the scale of large food retail businesses - the current value of the grocery market is £195.3 billion and set to grow further. This, combined with the highly competitive nature of the food retail industry, means there’s a very low likelihood that the small cost of any changes will be reflected in consumers’ shopping baskets.

In addition we have found that there isn’t a strong link between the health score of a retailer and the average cost of a basket of food sold by them. So when it comes to implementing targets, budget supermarkets aren’t at a disadvantage compared to high-end retailers. The healthy food standard should bring benefits to everyone - regardless of what they can spend. This is essential given the health inequalities affecting low-income families.

Food purchased in the out-of-home sector (which includes restaurants, coffee shops and takeaways) tends to be much higher in calories than food bought to eat at home, and it is less regulated than grocery retail.

Ideally the retail and out-of-home sectors would be regulated together, but to maximise public health impact, the evidence points to implementing targets for supermarkets first. The impact of targets for supermarkets is likely to be significantly higher than for out-of-home businesses (~20% reduction in prevalence of obesity over three years compared to ~2.5%). This is because sales from major supermarkets account for a much higher proportion of our diets (over 80%).

On top of this, critical policy questions around implementing health targets for out–of-home businesses remain unanswered, and solving them requires data from large out-of-home companies on the healthiness of their sales. The government should press ahead with mandatory data reporting for all food businesses, so that a clear health metric and target for out-of-home can then be set.

Setting ambitious health targets for supermarkets alone could lead to around 3 million fewer people in the UK living with obesity and help achieve government goals like halving the gap in healthy life expectancy. This divide currently spans seven years between regions and up to 18 years between local areas.

To realise this potential, the UK government must move quickly to implementation, ensuring the policy is not weakened or delayed in ways that reduce its impact. At Nesta, we recommend a phased approach: legislation covering supermarkets first, followed by the OOH sector and establishing powers for mandatory data reporting, mandatory targets and enforcement mechanisms within this Parliament. This will give targets enough time to incentivise compliance and maximise impact before the end of this Parliament.

We believe the healthy food standard sets a workable path forward for the food industry to actively help improve the nation's health. If implemented well, it could end decades of inaction and ensure that everyone - regardless of where they live or what they earn - has access to healthier choices. This policy is just one piece of the puzzle of halving obesity, but it's a vital one. With government, industry and individuals each playing their part, we can turn the tide on obesity and improve the nation's health for good.