Outside of China, the world now has more food insecure and nutrient deficient people than it had a decade ago, and the prevalence of obesity-related diabetes, high blood pressure and cardio-vascular diseases is increasing at very rapid rates. Expanded food production has done little to address the fact that between one-third and one-half of all deaths in children under five in developing countries are still related to malnutrition.

“With only three years away from the Millennium Development Goals deadline, this is a terrible track record,” said food and nutrition policy expert Per Pinstrup-Andersen at FSE's Global Food Policy and Food Security Symposium Series last week.  

Pinstrup-Andersen, the only economist to win the World Food Prize (the ultimate award in the food security field), has dedicated his career to understanding the linkages between food, nutrition, and agriculture. What is driving persistent food insecurity and malnutrition in a food abundant world?

Poor food supply management is part of the problem. According to the United Nations Food and Agricultural Organization (FAO), 20-30% of food produced globally is lost every year. That’s enough to feed an additional 3-3.5 billion people.

Jatropha in Africa. Photo credit: Ton Rulkens/flickr.

Biofuels production, such as jatropha in Africa, now competes with food for land, and climate change is already negatively impacting crop yields in regions straddling the equator—with major implications for food supply.

For low-income consumers in both the U.S. and developing countries increasing and more volatile food prices, such as those seen in 2007, are also driving food insecurity. Poor consumers respond by purchasing cheaper, less nutrient food, and less of it.

Nutritional value chain

Consensus is developing—at least rhetorically—among national policymakers and international organizations that investments in agricultural development must be accelerated. Members of the G8 and G20 have committed $20 billion in international economic support for such investments and some developing countries such as Ethiopia and Ghana are planning large new investments.

While most of these recent initiatives focus on expanded food supplies, there is an increasing understanding that merely making more food available will not assure better food security, nutrition, and health at the household and individual levels.

“It matters for health and nutrition how increasing food supplies are brought about and of what it consists,” said Pinstrup-Andersen. “We need to turn the food supply chain into a nutritional value chain.”

Diet diversity is incredibly important for good nutrition. Agricultural researchers and food production companies need to look at a number of different commodities, not just the major food staples, said Pinstrup-Andersen.

“The Green Revolution successfully increased the production of corn, rice, and wheat, increasing incomes for farmers, and lowering prices for consumers, but now it is time to invest in fruits, vegetables and biofortification to deal with micronutrient deficiency,” said Pintrup-Andersen.

Biofortification, the breeding of crops to increase their nutritional value, offers tremendous opportunity for dealing with malnutrition in the developing world, but is not widely available.

This is particularly important for areas in sub-Saharan Africa where between one and three and one and four people are short in calories, protein, and micronutrients. Obesity is actually going up in these countries with the introduction of cheap, processed, energy-dense foods (those high in sugar and fat) contributing to the diabetes epidemic.

Pathways to better health

Women hauling water to their gardens in Benin.

The path to better health and nutrition must look beyond the availability of food at affordable prices, clean water, and good sanitation, and consider behavioral factors such as time constraints for women in low-income households.

“Field studies have shown time and time again that one of the main factors preventing women from providing themselves and their families with good nutrition is time,” explained Pinstrup-Andersen.

He told the story of a woman in Bolivia too burdened with farm and household responsibilities to take the time to breastfeed her six-month old daughter. Enhancing productivity in activities traditionally undertaken by women could be a key intervention to improving good health and nutrition at the household level.

Access is another issue. A household may be considered food secure, in that sufficient food may be available, but food may not be equally allocated in the household.

“If we focus on the most limiting constraint we can be successful,” said Pinstrup-Anderen. “But we must tailor our response to each case.”

For sub-Saharan Africa, this includes investments in rural infrastructure, roads, irrigation systems, micronutrient fertilizer, climate adaptation strategies, and other barriers holding back small farmers.

Fortunately, there has been a renewed attention to the importance of guiding food system activities towards improved health and nutrition. The Global Agriculture and Food Security Program (GAFSP), which facilitates the distribution of some of the G8 and G20 $20 billion commitments, prescribes that country proposals for funding of agricultural development projects must show a clear pathway from the proposed agricultural change to human nutrition.

“But it’s not going to be easy to implement good policies,” warned Pinstrup-Andersen. “There are few incentives in government for multidisciplinary problem solving. The economy is set up around silos and people are loyal to their silos. Agricultural and health sectors are largely disconnected in their priorities, policy, and analysis."

Incentives must change to encourage working across ministries and disciplines to identify the most important health and nutrition-related drivers of food systems, impact pathways, and policy and program interventions to find win-wins for positive health and nutrition.

Instilling healthy eating and exercise habits in children may help prevent obesity later in life. But which kids most need such obesity-prevention efforts? A recent study by Jeremy Goldhaber-Fiebert and colleagues at Stanford's School of Medicine showed that this question is harder to answer than it seems. The study, published earlier this year in Medical Decision Making, found that targeting obesity prevention to small children who are overweight might not be effective. That's because a higher-than-normal weight at age 5 provides an accurate predictor of adult obesity only 50 percent of the time.

Goldhaber-Fiebert, an assistant professor of medicine and core faculty member of Stanford Health Policy, discusses the problem.

What does your paper tell us about the recent focus on childhood and adolescent obesity measurements?

Our study has two take-home messages. First, while childhood obesity is an important problem, solving childhood obesity alone will not solve future adult obesity problems. Second, addressing future adult obesity will require broader societal measures — not simply interventions focused on obese children.

It used to be that no one worried much if a small child was chubby; the doctor might say, "It's baby fat, he'll grow out of it." How has that changed?

In fact, our data show that many children still do "grow out of it." But our findings suggest that it is difficult to predict whether this will happen for a specific child. Consequently, efforts to help obese children must be connected to broader efforts to create healthy diets and habits for all children.

Childhood obesity is concerning both because it presents increased health risks for individuals while they are children and also because of the fear that it will translate into serious adult obesity-related health issues. Our analyses show that targeting children who are already obese is unlikely to be sufficient in addressing broader public health challenges of obesity in later childhood, adolescence and adulthood.

Are there other more promising screening criteria for chronic adult obesity instead of using a child's weight?

It really depends on the purpose of screening. Researchers have identified a variety of characteristics to predict a child's future obesity status — for example, easily observed measures like the weight of a child's parent as well as more complex measures such as their size at birth and the rapidity with which they subsequently grew and gained weight.

The challenge is to have a measure that both does not miss a substantial fraction of those who become obese later on and also does not falsely predict obesity for a large number of those who do not become obese as adults. The trade-off between these two types of errors depends on the seriousness of health implications of obesity and the costs of treating health conditions once they arise, as well as the health and economic costs of delivering preventive interventions to people who are identified as being at risk of becoming obese regardless of whether they become obese in the future.

What are some of the best potential approaches for reducing childhood obesity if the entire population is being targeted?

Given that many health-related habits are developed in childhood, efforts to create healthy eating and exercise habits in children would seem to be beneficial. But for most potential interventions, we lack evidence of their widespread effectiveness over a long period of time. Do reductions in obesity persist from childhood into adulthood? Do they lead to measurable improvements in health outcomes? We do not have answers to these key questions.

Food, beverage or sugar taxes and other manipulations to food prices or availability may be effective, but may also have unintended harms and certainly come at the cost of curtailing personal choice. Re-engineering the built environment or nudging people with various behavioral/economic mechanisms have garnered attention though, again, widely generalizable evidence on them is lacking. The problem deserves continued creativity and ongoing evaluation and testing.

Your paper focuses on which obese children will become obese adults, yet we are seeing a growing number of children experiencing type-2 diabetes and other negative health consequences of being overweight before they're even out of their teen years. Is adult obesity the best endpoint to focus on?

Obesity-related conditions of childhood clearly should not be ignored. What we are concerned about is the sense that people were conflating good care for children to deal with their shorter-term health needs (i.e., childhood obesity management to deal with childhood health issues) and the belief that such an approach might largely solve the broader adult obesity issues. Addressing childhood obesity is still important even if it does not fix adult obesity and its deleterious health consequences.

Erin Digitale is the pediatrics writer for Stanford School of Medicine's Office of Communication and Public Affairs.