But what about the research community? Why should they pay any attention to the report? After all, it presents no new research, just a different way of combining data and highlighting new ideas.
In my view, this is the report’s main added value for research: it identifies and raises a number of pertinent research questions. In this article, I want to highlight four areas where I think these questions should be of particular interest to future research.
Understanding the winners
According to the data in the report, several countries are doing exceptionally well in terms of nutrition: Colombia is the only country on track to meet four of the six nutrition targets, while China and South Korea are the only two countries not to have serious public health issues with stunting, anaemia in women of reproductive age and adult obesity. But what is special about them? And why are relatively well-off countries such as Indonesia off track? Country case studies have fallen foul of the current fashion for sliced-and-diced randomised controlled trials. Instead we need more joined-up studies that follow the outcomes over time, to complement the studies that follow the interventions that have worked.
The report also highlights wide differentials in the reach of practices and interventions in various countries — and we know that malnutrition is reduced much more slowly without scaled-up interventions. Again, why do some countries do well and others not? And why does a given country do well on some interventions and not on others?
Understanding policy design issues
In the area of nutrition-sensitive interventions, the report focuses on discrete agricultural and social protection programmes. But this leaves crucial questions unanswered. Looking at the big picture, are there any winning policy designs? Is there a link between the composition of a country’s agricultural research and development and its nutrition outcomes? What is the scope for schemes such as India’s Public Distribution System to subsidise more nutritious foods, and would it help to diversify diets?
One area we were surprised to find little data for is nutrition costing in national budgets. As we begin to collect more of this data this year, the questions will follow. How do budget allocations vary across countries? Why and how do these compare with budgets in other sectors? Do countries allocate resources to the areas their national nutrition plans say they should?
Similar questions can be asked about external donor funding. But when we ask how private sector efforts affect nutrition status, we enter a real black box. The private sector already influences choices in food, health and exercise, frequently making it harder to make healthy choices. At the same time, there are many areas of involvement with potentially low risk and high payoff, such as manufacturing fortified grains and using mobile phones for knowledge sharing.
- When will we have more randomised, long-term studies?
- Why are some countries high achievers?
- How do we make sense of data on wasting?
- How do we match interventions to different country contexts?
- What’s the link between country research investments and nutrition outcomes?
- Does funding usually match nutrition priorities?
- How does the private sector affect nutrition?
- Do social accountability tools work?
- What are the returns on data collection?
What policies lead to more sustainable diets?
Ten research questions on nutrition
New investments in research and programmes
The report calls for a data revolution in nutrition. Nearly 50 per cent of all countries cannot track all four health status indicators and only 40 per cent of countries measure the height and weight of young children over five years old. This seems unacceptable, but how good an investment is nutrition data? For example, we know that a national nutrition survey typically costs about US$1 million, but what are the benefits?
Similarly, we need to understand the trade-offs for accountability tools and how they work. The report advocates greater experimentation with such tools in nutrition on the basis that they seem to be effective in other sectors.  These experiments need to take place and then be evaluated properly, with quantitative and qualitative methods.
Next, consider the long-term benefits of improved nutrition. A Guatemalan study by John Hoddinott and colleagues is really unusual in having a powerful design that links the benefits of a feeding intervention in kids under the age of three to their increased earnings as adults 30 years later.  But how long can we rely on a single study’s estimates? Many more randomised controlled trials in nutrition have started in the past ten years, and donors must consider funding to follow up some of them 25 years down the road.
Then there are the specifics: there is too much focus on stunting (low height for age) and less on wasting (low weight for height). In fact wasting is an important contributor to stunting, so it has relevance. But we should have more interest in it for its own sake, as it is just as serious a condition as stunting, and declining much more slowly.
Intersections with other agendas
How can we get input from private sector stakeholders without ceding control of the public health agenda? The field is crying out for a review of the landscape of nutrition and the private sector that highlights areas of consensus and disagreement, and how to capitalise on the first — assessed with independent evaluations — and minimise and then monitor the latter.
Finally, climate and nutrition. The report was relatively silent on this, but it is an emerging area and this is an important year for climate talks. On the mitigation side, one idea is to form new alliances under the banner of sustainable and healthy diets.  Alliances or not, what are the policy levers that will lead us towards these sustainable diets? And on the adaptation side, what should nutrition programmers be doing differently in the context of greater climate uncertainty?
These are great research questions — and there are others. They are challenging, but answers are needed. What more could a researcher want?
Lawrence Haddad is a senior research fellow at the International Food Policy Research Institute and former director at the Institute of Development Studies. He is co-chair of the Global Nutrition Report’s Independent Expert Group. @l_haddad
References Global nutrition report 2014 (International Food Policy Research Institute, November 2014)
 Anuradha Joshi Do they work? Assessing the impact of transparency and accountability initiatives in service delivery (Development Policy Review, August 2013)
 John Hoddinott and others Effect of a nutrition intervention during early childhood on economic productivity in Guatemalan adults (The Lancet, February 2008)
 David Tilman and Michael Clark Global diets link environmental sustainability and human health (Nature, November 2014)