Sugar restrictions in utero and early childhood reduces risk of chronic disease, study finds

A toddler gets her hands on some candy at a Halloween event in Ashland, Ky. (Kevin Goldy/The Daily Independent via AP)

A low-sugar diet in utero and in the first two years of life can meaningfully reduce the risk of chronic diseases in adulthood, according to a study published today in the journal Science. The researchers used contemporary data from the U.K. Biobank to study the effect of exposure to sugar restrictions early in life on health outcomes of adults conceived just before and after the end of wartime sugar rationing in the United Kingdom in September 1953.

The study, published on Halloween, finds that children exposed to sugar restrictions during their first 1,000 days—including in utero—had up to a 35% lower risk of developing Type 2 diabetes and up to 20% lower risk of hypertension as adults. In-utero exposure alone was enough to lower risks, but disease protection increased with length of exposure after birth.

The study—a collaboration by researchers Tadeja Gracner from the University of Southern California, Claire Boone of McGill University, and Paul Gertler of the University of California Berkeley’s Haas School of Business—provides compelling new evidence of the lifelong health effects of early-life sugar exposure.

“Studying the long-term effects of added sugar on health is challenging because it is hard to find situations where people are as-if randomly exposed to different nutritional environments early in life and follow them for 50 to 60 years,” said Gracner (PhD 15, Economics). “The end of rationing provided us with a novel natural experiment to overcome these problems.”

Wartime sugar rationing

The study exploits a natural experiment: the end of sweets and sugar wartime rationing in the U.K. during World War II. Rationing was in effect during the war and ended in September 1953. Sugar intake during that time was about half (around 40 grams per day) the level immediately following rationing. The rationing was not one of extreme food deprivation—in fact, diets generally appeared to have been within today’s USDA/WHO dietary guidelines.  WHO,  as well as Dietary Guidelines for America adopted in 2020, recommend that children under two should consume no added sugars, and adults should aim to limit their added sugar intake to 7 teaspoons per day and consume no more than 12 teaspoons (50g).

When rationing ended, sugar and sweets consumption skyrocketed–doubling to about 80 grams per day on average. Other foods, like butter, cheese, cereals, and meat were also rationed, but there was little if any change in their consumption after rationing ended. Almost all of the sharp increase in total calorie intake post-rationing was explained by the rise in sugar calorie intake.

The end of WWII rationing therefore created a natural experiment in which children born just before the end of rationing were exposed to sugar-scarce conditions compared to those born just after who were born into a sugar-rich environment. The researchers then identified those born around this time in the UK Biobank data collected more than 50 years later. Enough time has passed since then for chronic diseases to develop and using a very tight birth window around the end of WWII sugar rationing allowed the authors to compare midlife health outcomes of otherwise similar birth cohorts.

Less diabetes, hypertension

The authors found that exposure to sugar restrictions in utero and during the first 1,000 days substantially lowered the risk of developing Type 2 diabetes and hypertension. If diagnosed, reduced early-life sugar intake delayed onset of diabetes by four years and hypertension by two years, respectively. In-utero exposure alone was enough to lower risks, but disease protection increased with the length of time babies had limited exposure to added sugar.

The magnitude of this effect is meaningful as it can save costs, extend life expectancy and, perhaps more importantly, improve quality of life. In the U.S., people with diabetes incur annual medical expenditures of about $12,000 on average. Every decade of earlier diagnosis of diabetes is associated with three-to-four years lower life expectancy, underscoring the value of early interventions that could delay or prevent this disease.

Policy implications

Today, there is a growing concern about children’s long-term health as they are consuming excessive amounts of added sugars during this critical early period. Added sugar is everywhere—even in baby and toddler foods—and children are bombarded with TV ads for sugary snacks. Adjusting sugar consumption is not easy, the researchers acknowledge, but information is key. “Parents need information about what works, and this study provides some of the first casual evidence that reducing added sugar early in life is a powerful step towards improving children’s health over their lifetimes,” said Boone (PhD 22, Public Health).

Gertler adds, “Sugar early in life is the new tobacco, and we should treat it as such by holding food companies accountable to reformulate baby foods with healthier options. We should also tax and regulate the marketing of sugary foods targeted at kids.”

This is the first study out of a larger research effort exploring how early-life sugar restrictions affect a broader set of economic and health outcomes including education, wealth, chronic inflammation, cognitive function, and dementia in later adulthood.

The study was supported by the U.S. National Institutes on Aging, part of the National Institutes of Health.

About the study

“Exposure to Sugar Rationing in the First 1000 Days of Life Protected Against Chronic Disease”
by Tadeja Gracner, Claire Boone and Paul J. Gertler
Science, October 31, 2024

News coverage

How to spot societal tipping points in real time

Social scientists are using new methods to study pivotal societal turning points in real time. What they are learning could shape how policymakers address democratic backsliding, environmental crises, and other key challenges of our time.

Egyptian protesters attend a demonstration at the Tahrir Square in Cairo, Egypt, Friday, March 4, 2011. (AP Photo/Khalil Hamra)

The French Revolution, the fall of the Berlin Wall, Fidel Castro seizing power in Cuba—events like these fundamentally transform societies and how people within them live. Other moments seem equally full of potential for radical change, but the status quo prevails. For example, the 1989 Tiananmen Square protests in China and the 2011 Arab Spring uprising didn’t lead to lasting shifts in political and economic institutions.

Social scientists studying these rare historical turning points—which they call “critical junctures”—usually only look backward, evaluating how these moments remade institutions after a massive shift occurs. But researchers are now learning more by studying these crossroads as they are occurring, according to a new paper published in the Annual Review of Economics.

“If we identify critical junctures in real time, we can embed survey measurement and experiments in these contexts,” says Assistant Professor Jonathan Weigel, who co-authored the paper with Noam Yuchtman of Oxford and Michael Callen of the London School of Economics and Political Science. “That can help us understand why some countries get on an institutional path that leads to prosperity and others are stuck on one that leads to ruin. Is it really a coin flip, or are there certain things a leader can do in these moments of deep uncertainty?”

“If we identify critical junctures in real time, we can embed survey measurement and experiments in these contexts. That can help us understand why some countries get on an institutional path that leads to prosperity and others are stuck on one that leads to ruin. Is it really a coin flip, or are there certain things a leader can do in these moments of deep uncertainty?” —Jonathan Weigel

Studying critical junctures while they are happening can allow scholars to test competing theories about what causes institutional change, such as class conflict or social movements. Academics define institutions as the fundamental “rules of the game” that shape incentives and behavior—for example, a democratic versus an autocratic political regime. The empirical study of institutions was pioneered by Daron Acemoglu, Simon Johnson, and former UC Berkeley faculty James Robinson, who won the 2024 Nobel Prize in Economics for their contribution.

Identifying the potential for negative upheaval in the moment could also help policymakers intervene. For example, “if we value democracy, the ability to recognize when it’s truly under threat versus just grandiose rhetoric is important,” Weigel says. “Many Americans are asking themselves this question about our democracy right now.”

A new research approach

Traditional retrospective studies alone are limited because they leave out many critical junctures in which institutional change did not occur. To address this gap, Weigel and his co-authors argue that scholars can recognize pivotal moments in the present by regularly asking people what they predict the future of key institutions will be.

“For example, researchers might ask, ‘How will political power be allocated in five years?’” Weigel says. “If everyone agrees that power will be determined through democratic elections, then the society does not appear to be in a critical juncture.” If, however, many people seem uncertain, or if expectations vary widely across society, that could signal a critical juncture in which multiple future paths are possible.

One example of such a survey was deployed in Afghanistan, where NATO asked 11,500 citizens each quarter whether they believed the Afghan army would defeat the Taliban in the next few years. In 2008, when the survey started, just under 40% predicted the army would win, nearly a quarter thought it would lose, and one-third weren’t sure. This deep uncertainty about the country’s institutional future suggests that Afghanistan was in the throes of a critical juncture, Weigel says.

“You can observe how those beliefs responded to real changes in the world, such as the announcement of a surge in U.S. troop deployments,” he says. “That gives us a sense that beliefs can be a useful barometer for understanding the potential for institutional change and whether we’re getting close to a critical juncture.”

“You can observe how those beliefs responded to real changes in the world, such as the announcement of a surge in U.S. troop deployments. That gives us a sense that beliefs can be a useful barometer for understanding the potential for institutional change and whether we’re getting close to a critical juncture.” —Jonathan Weigel

Weigel and his colleagues are now building on their work by trying to embed a question on beliefs about institutions in a global survey and launching a study that will use artificial intelligence to analyze newspaper archives to identify historical and current critical junctures.

Meanwhile, Weigel points to growing disagreement about the integrity of U.S. elections as a warning sign that the country’s political system is under threat. “A large part of the electorate claims the 2020 election was stolen, and many people are reportedly planning for what happens if the 2024 elections aren’t respected. These are signs of disagreement over the future rules of the game that would suggest we’re in a critical juncture,” he says—though he does not know of any systematic measurement of these beliefs to date. “Someone should collect them!” he adds.

Work in the Democratic Republic of Congo

Weigel, who joined Haas in 2021, has been working in this field since starting his PhD in political economy and government at Harvard University in 2012. For over a decade, he has collaborated with the provincial government of the Democratic Republic of Congo, one of the world’s poorest countries, to conduct randomized control trials related to state capacity, primarily focusing on taxation.

In the DRC, the formal state lacks legitimate authority. Many actors vie for political control, and there is widespread disagreement about the future of institutions. Weigel’s research seeks to understand the state’s efforts to build its capacity and accumulate legitimacy. His study of the provincial capital Kananga’s first citywide property tax collection campaign found that it not only raised substantial revenue but also increased citizens’ perceptions of government performance and boosted political participation and demand for political accountability.

Research on institutions and randomized control trials used to be seen as separate areas of study with nothing in common. Weigel and his colleagues point out that a new body of research has emerged that bridges the gap.

“I remember a senior political economist saying, ‘You could never run a randomized controlled trial about something I’m interested in,’” Weigel says. “That was the mood for a long time.” But things are starting to change.

A growing field

Over the past 15 years, studies that use randomized controlled trials to analyze critical junctures in real time to better understand institutional change have increased fivefold, Weigel and his colleagues point out. Already, the growing field has yielded insights about the ability of states to strengthen the social compact, improve law enforcement, and expand political inclusion and accountability.

For example, recent experiments have found that giving voters more say over who parties pick as political candidates improved democratic representation in Sierra Leone; that widely deploying an election monitoring technology improved perceptions of election integrity and willingness to engage with formal state institutions in Afghanistan; and that letting companies comment on new labor laws in Vietnam increased compliance even when regulations were unchanged.

The researchers argue that expanding this area of study can shed light on key current issues, such as declines in democratic freedoms, the effects of climate change on institutions, and the rights of marginalized groups.

Inspired by Paul Farmer

Weigel’s interest in these topics dates to his time as an undergraduate at Harvard, where he studied with the late Paul Farmer, founder of Partners In Health. After graduating, Weigel spent two years as a researcher for the organization, which works with local governments to provide health care in the world’s poorest places.

“Paul had an incredible commitment to understanding the reasons why Haitians were so poor when just across the border, the Dominican Republic was much more successful,” he says. “My underlying interest is what lies at the root of why some countries have so much and other countries have so little.”

Weigel was inspired by the Partners In Health model of collaborating closely with local governments, rather than trying to build parallel structures to provide services, as many NGOs do. To that end, he founded a research organization in the DRC called ODEKA to work with the government and evaluate its efforts to build state capacity. He has led multiple randomized controlled trials that have led to improved tax collection and higher rates of political participation and is now working with ODEKA to evaluate the rollout of a more progressive and fully digitized property tax system in Kananga, DRC. “Collaborating closely with our Congolese colleagues has been one of the incredibly rewarding parts of my work,” Weigel says.

ODEKA employs a staff of nearly 70. “A lot of my papers are inspired by this close partnership,” he says. “I also personally feel really good about getting to provide stable employment for an outstanding set of individuals for the past 11 years.”

Read the full paper:

Experiments About Institutions
By Michael Callen, Jonathan L. Weigel, and Noam Yuchtman
Annual Review of Economics, August 2024

Meet the faculty: Top-tier researchers join Berkeley Haas for 2024-25

A collage shows headshots of a man and a women side-by-side: Kelsey Jack and James Sallee.
Associate Professor Kelsey Jack and Professor James Sallee joined the faculty on July 1.

Two top-tier researchers whose work addresses pressing environmental, development, and public policy questions have joined the ranks of Berkeley Haas professors this semester. Two additional professors will join the faculty in January 2025. 

“Our new faculty hires this year are leading researchers and teachers who will help to solidify our emphasis on sustainability,” says Interim Dean Jenny Chatman. “We’re so thrilled they are bringing their brilliance to Haas—and to the greater UC Berkeley community.”

“Our new faculty hires this year are leading researchers and teachers who will help to solidify our emphasis on sustainability. We’re so thrilled they are bringing their brilliance to Haas—and to the greater UC Berkeley community.” —Interim Dean Jenny Chatman

Associate Professor Kelsey Jack, whose work lies at the intersection of environmental and development economics, comes to Haas from the University of California, Santa Barbara, where she was an associate professor at the Bren School of Environmental Science and Management and the Department of Economics. 

Professor James Sallee is already a familiar face around campus. As a faculty member in the Department of Agricultural and Resource Economics at UC Berkeley since 2015 and a faculty affiliate at the Energy Institute at Haas since 2016, his research focuses on energy, the environment, climate, and public economics, with a focus on public policy.

In January, Berkeley Haas will welcome Economist Martin Beraja of MIT will join the Economic Analysis and Policy group as an assistant professor, and Dr. David Chan, a health economist and MD now at Stanford University, will join the Economic Analysis and Policy group as a professor. Chan will serve as the new faculty director for the Robinson Life Science, Business, and Entrepreneurship Program.

Associate Professor Kelsey Jack, Sheth Sustainable Business Chancellor’s Chair

Pronouns: she/her
Hometown: Van Zandt, Washington
Academic Group: Business and Public Policy

Education

  • PhD, Public Policy, Harvard University
  • AB, Public and International Affairs, Princeton University

Research focus: Environmental and development economics

Introduction: I am joining Haas from the University of California, Santa Barbara, where I was an associate professor at the Bren School of Environmental Science and Management and the Department of Economics. Prior to that, I was an associate professor at Tufts University. I also spent a year at UC Berkeley in 2013-14 as visiting faculty in the Department of Agricultural and Resource Economics.

I study questions at the intersection of environmental and development economics. In particular, I try to understand how low income households use natural resources—land, water, energy—and the ways that policy can help align short-run economic needs with longer-run environmental and health concerns. I’ve thought about this topic for a long time, since a family trip to Madagascar after my freshman year in high school; it’s remained the problem that interests me most in the world. For example, at the moment, I’m studying climate adaptation in Niger and clean energy adoption in Ghana. I have other projects underway in India, South Africa, Malawi and Ivory Coast. 

“I try to understand how low income households use natural resources—land, water, energy—and the ways that policy can help align short-run economic needs with longer-run environmental and health concerns. I’ve thought about this topic for a long time, since a family trip to Madagascar after my freshman year in high school.” —Associate Professor Kelsey Jack

Teaching: I am creating a new course, tentatively titled “Sustainable Markets: Profit, Policy, and Corporate Responsibility”

Why you decided to join Berkeley Haas:  Amazing colleagues! 

Fun (nonacademic) fact about you: I spent two years after college living in Vientiane, Lao People’s Democratic Republic (Laos) working for an environmental organization and figuring out what to do with my life. 

Professor James Sallee

Pronouns: he/him
Hometown: Bloomington, Illinois
Academic Group: Economic Analysis and Policy

Education:

  • PhD, Economics, University of Michigan 
  • BA, Economics and Political Science, Macalester College

Research focus: Energy, the environment, climate, and public economics, with a focus on public policy

Introduction: I always knew that I wanted to be an academic, to research, write and teach. So I went more or less straight through to my PhD after college. I fell in love with economics towards the end of college because I saw it as a versatile tool that could be used to study a variety of important problems. In graduate school, I was studying tax policy, partly because it interested me and partly because that was where I found the best mentorship. But, I fell almost by accident into a dissertation topic that studied tax subsidies for hybrid cars. As I learned more about environmental issues, I became more and more interested, and my career has ever since drifted more and more towards the biggest environmental problems of the day. I now study topics ranging from retail electricity pricing reforms in California to the design of public policies to ensure equity in the energy transition. For the last several years, I’ve worked with collaborators in the Rausser College of Natural Resources and at Haas to launch a brand new master’s program called the Master of Climate Solutions, which will be an interdisciplinary professional program that equips students to help become change agents for the climate across industries and sectors.

“As I learned more about environmental issues, I became more and more interested, and my career has ever since drifted more and more towards the biggest environmental problems of the day. I now study topics ranging from retail electricity pricing reforms in California to the design of public policies to ensure equity in the energy transition.” —Professor James Sallee

Class(es) you’ll teach: Core microeconomics

Why you decided to join Berkeley Haas: I have always loved professional education because it feels impactful to help equip students who are going to jump back into leadership roles right after school. I like the back-and-forth with students who bring not just intellectual curiosity, but also a wealth of experience to the classroom dialogue. I like that professional students demand that material is relevant and practical. I was also drawn to the opportunity to push Haas as the leader in climate and sustainability. My research and policy attention has moved more and more towards the climate challenge in recent years, and I believe that business can and must drive progress on climate.

Fun (non-academic) fact about you: I spent most of my money and all of my energy outside of work taking care of my three daughters. I love to travel and enjoy cooking.

Professional Faculty

In addition to the new members of the ladder faculty, nine new lecturers will be teaching courses this fall. Several others will join in spring (with additions exepected mid-year). They include:

  • Helene York, Responsible Business
  • Kate Gordon, Sustainable & Impact Finance
  • Rebekah Butler, Business & Public Policy
  • Alex Luce, Economic Analysis & Policy
  • Ana Martinez, Economic Analysis & Policy
  • Miyoko Schinner, Sustainable & Impact Finance
  • Jules Maltz, Entrepreneurship & Innovation
  • Richard Wuebker, Finance
  • Asiff Hijiri, Finance/Entrepreneurship & Innovation
  • queen jaks, Management of Organizations (spring 2025)
  • Bianca Datta, Sustainable & Impact Finance (spring 2025)