Marie Ng, University of Washington

Nearly half of adolescents and three-quarters of adults in the U.S. were classified as being clinically overweight or obese in 2021. The rates have more than doubled compared with 1990.

Without urgent intervention, our study forecasts that more than 80% of adults and close to 60% of adolescents will be classified as overweight or obese by 2050. These are the key findings of our recent study, published in the journal The Lancet.

Synthesizing body mass index data from 132 unique sources in the U.S., including national and state-representative surveys, we examined the historical trend of obesity and the condition of being overweight from 1990 to 2021 and forecast estimates through 2050.

For people 18 and older, the condition health researchers refer to as “overweight” was defined as having a body mass index, or BMI, of 25 kilograms per square meter (kg/m²) to less than 30 kg/m² and obesity as a BMI of 30 kg/m² or higher. For those younger than 18, we based definitions on the International Obesity Task Force criteria.

This study was conducted by the Global Burden of Disease Study 2021 U.S. Obesity Forecasting Collaborator Group, which comprises over 300 experts and researchers specializing in obesity.

Why it matters

The U.S. already has one of the highest rates of obesity and people who are overweight globally. Our study estimated that in 2021, a total of 208 million people in the U.S. were medically classified as overweight or obese.

Obesity has slowed health improvements and life expectancy in the U.S. compared with other high-income nations. Previous research showed that obesity accounted for 335,000 deaths in 2021 alone and is one of the most dominant and fastest-growing risk factors for poor health and early death. Obesity increases the risk of diabetes, heart attack, stroke, cancer and mental health disorders.

The economic implications of obesity are also profound. A report by Republican members of the Joint Economic Committee of the U.S. Congress, published in 2024, predicted that obesity-related health care costs will rise to US$9.1 trillion over the next decade.

The rise in childhood and adolescent obesity is particularly concerning, with the rate of obesity more than doubling among adolescents ages 15 to 24 since 1990. Data from the National Health and Nutrition Examination Survey revealed that nearly 20% of children and adolescents in the U.S. ages 2 to 19 live with obesity.

By 2050, our forecast results suggest that 1 in 5 children and 1 in 3 adolescents will experience obesity. The increase in obesity among children and adolescents not only triggers the early onset of chronic diseases but also negatively affects mental health, social interactions and physical functioning.

What other research is being done

Our research highlighted substantial geographical disparities in overweight and obesity prevalence across states, with southern U.S. states observing some of the highest rates.

Other studies on obesity in the United States have also underscored significant socioeconomic, racial and ethnic disparities. Previous studies suggest that Black and Hispanic populations exhibit higher obesity rates compared with their white counterparts. These disparities are further exacerbated by systemic barriers, including discrimination, unequal access to education, health care and economic inequities.

Another active area of research involves identifying effective obesity interventions, including a recent study in Seattle demonstrating that taxation on sweetened beverages reduced average body mass index among children. Various community-based studies also investigated initiatives aimed at increasing access to physical activity and healthy foods, particularly in underserved areas.

Clinical research has been actively exploring new anti-obesity medications and continuously monitoring the effectiveness and safety of current medications.

Furthermore, there is a growing body of research examining technology-driven behavioral interventions, such as mobile health apps, to support weight management. However, whether many of these programs are scalable and sustainable is not yet clear. This gap hinders the broader adoption and adaptation of effective interventions, limiting their potential impact at the population level.

What’s next

Our study forecasts trends in overweight and obesity prevalence over the next three decades, from 2022 to 2050, assuming no action is taken.

With the advent of new-generation anti-obesity medications, obesity management could change substantially. However, the extent of this impact will depend on factors such as cost, accessibility, coverage, long-term efficacy and variability in individual responses. Future research will need to leverage the most up-to-date evidence.

The Research Brief is a short take on interesting academic work.

Marie Ng, Affiliate Associate Professor of Global Health, University of Washington

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Liza M. Hinchey, Wayne State University

Political chasms, wars, oppression … it’s easy to feel hopeless and helpless watching these dark forces play out. Could any of us ever really make a meaningful difference in the face of so much devastation?

Given the scale of the world’s problems, it might feel like the small acts of human connection and solidarity that you do have control over are like putting Band-Aids on bullet wounds. It can feel naive to imagine that small acts could make any global difference.

As a psychologist, human connection researcher and audience member, I was inspired to hear musician Hozier offer a counterpoint at a performance this year. “The little acts of love and solidarity that we offer each other can have powerful impact … ” he told the crowd. “I believe the core of people on the whole is good – I genuinely do. I’ll die on that hill.”

I’m happy to report that the science agrees with him.

Research shows that individual acts of kindness and connection can have a real impact on global change when these acts are collective. This is true at multiple levels: between individuals, between people and institutions, and between cultures.

This relational micro-activism is a powerful force for change – and serves as an antidote to hopelessness because unlike global-scale issues, these small acts are within individuals’ control.

Abstract becomes real through relationships

Theoretically, the idea that small, interpersonal acts have large-scale impact is explained by what psychologists call cognitive dissonance: the discomfort you feel when your actions and beliefs don’t line up.

For example, imagine two people who like each other. One believes that fighting climate change is crucial, and the other believes that climate change is a political ruse. Cognitive dissonance occurs: They like each other, but they disagree. People crave cognitive balance, so the more these two like each other, the more motivated they will be to hear each other out.

According to this model, then, the more you strengthen your relationships through acts of connection, the more likely you’ll be to empathize with those other individual perspectives. When these efforts are collective, they can increase understanding, compassion and community in society at large. Issues like war and oppression can feel overwhelming and abstract, but the abstract becomes real when you connect to someone you care about.

So, does this theory hold up when it comes to real-world data?

Small acts of connection shift attitudes

Numerous studies support the power of individual acts of connection to drive larger-scale change.

For instance, researchers studying the political divide in the U.S. found that participants self-identifying as Democrats or Republicans “didn’t like” people in the other group largely due to negative assumptions about the other person’s morals. People also said they valued morals like fairness, respect, loyalty and a desire to prevent harm to others.

I’m intentionally leaving out which political group preferred which traits – they all sound like positive attributes, don’t they? Even though participants thought they didn’t like each other based on politics, they also all valued traits that benefit relationships.

One interpretation of these findings is that the more people demonstrate to each other, act by act, that they are loyal friends and community members who want to prevent harm to others, the more they might soften large-scale social and political disagreements.

Even more convincingly, another study found that Hungarian and Romanian students – people from ethnic groups with a history of social tensions – who said they had strong friendships with each other also reported improved attitudes toward the other group. Having a rocky friendship with someone from the other group actually damaged attitudes toward the other ethnic group as a whole. Again, nurturing the quality of relationships, even on an objectively small scale, had powerful implications for reducing large-scale tensions.

In another study, researchers examined prejudice toward what psychologists call an out-group: a group that you don’t belong to, whether based on ethnicity, political affiliation or just preference for dogs versus cats.

They asked participants to reflect on the positive qualities of someone they knew, or on their own positive characteristics. When participants wrote about the positive qualities of someone else, rather than themselves, they later reported lower levels of prejudice toward an out-group – even if the person they wrote about had no connection to that out-group. Here, moving toward appreciation of the other, rather than away from prejudice, was an effective way to transform preconceived beliefs.

So, small acts of connection can shift personal attitudes. But can they really affect societies?

From one-on-one to society-wide

Every human being is embedded in their own network with the people and world around them, what psychologists call their social ecology. Compassionate change at any level of someone’s social ecology – internally, interpersonally or structurally – can affect all the other levels, in a kind of positive feedback loop, or upward spiral.

For instance, both system-level anti-discrimination programming in schools and interpersonal support between students act reciprocally to shape school environments for students from historically marginalized groups. Again, individual acts play a key role in these positive domino effects.

Even as a human connection researcher, I’ve been surprised by how much I and others have progressed toward mutual understanding by simply caring about each other. But what are small acts of connection, after all, but acts of strengthening relationships, which strengthen communities, which influence societies?

In much of my clinical work, I use a model called social practice — or “intentional community-building” – as a form of therapy for people recovering from serious mental illnesses, like schizophrenia. And if intentional community-building can address some of the most debilitating states of the human psyche, I believe it follows that, writ large, it could help address the most debilitating states of human societies as well.

Simply put, science supports the idea that moving toward each other in small ways can be transformational. I’ll die on that hill too.

Liza M. Hinchey, Postdoctoral Research Fellow in Psychology, Wayne State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Katarzyna Kordas, University at Buffalo

Spices bring up feelings of comfort, cultural belonging and holidays. They can make our homes smell amazing and our food taste delicious. They can satisfy our cravings, expand our culinary horizons and help us eat things that we might normally dislike. Spices have health-enhancing properties and, in medicine, have been used to heal people since the ancient times.

Recently, however, spices have been getting a bad rep.

In September 2024, Consumer Reports, a nonprofit organization created to inform consumers about products sold in the U.S., investigated more than three dozen ground cinnamon products and found that 1 in 3 contained lead levels above 1 part per million, enough to trigger a recall in New York, one U.S. state that has published guidelines for heavy metals in spices.

The Food and Drug Administration issued three alerts throughout 2024, warning consumers about lead in certain brands of cinnamon products. Such notices rightfully put consumers on alert and have people wondering if the spice products they buy are safe – or not.

As an environmental epidemiologist with training in nutritional sciences, I have investigated the relationship between nutritional status, diets and heavy metal exposures in children.

There are several things consumers should be thinking about when it comes to lead – and other heavy metals – in cinnamon.

Why is lead found in cinnamon?

Most people are familiar with cinnamon in two forms – sticks and ground spice. Both come from the dried inner bark of the cinnamon tree, which is harvested after a few years of cultivation. For the U.S. market, cinnamon is largely imported from Indonesia, Vietnam, Sri Lanka, India and China.

One way that lead could accumulate in cinnamon tree bark is when trees are cultivated in contaminated soil. Lead can also be introduced in cinnamon products during processing, such as grinding.

When ground cinnamon is prepared, some producers may add lead compounds intentionally to enhance the weight or color of the product and, thus, fetch a higher sale price. This is known as “food adulteration,” and products with known or suspected adulteration are refused entry into the U.S.

However, in the fall of 2023, approximately 600 cases of elevated blood lead levels in the U.S., defined as levels equal to or above 3.5 micrograms per deciliter – mostly among children – were linked to the consumption of certain brands of cinnamon apple sauce. The levels of lead in cinnamon used to manufacture those products ranged from 2,270 to 5,110 parts per million, indicating food adulteration. The manufacturing plant was investigated by the FDA.

More broadly, spices purchased from vendors in the U.S. have lower lead levels than those sold abroad.

There is some evidence that cinnamon sticks have lower lead levels than ground spice. Lead levels in ground cinnamon sold in the U.S. and analyzed by Consumer Reports ranged from 0.02 to 3.52 parts per million. These levels were at least 1,500 times lower than in the adulterated cinnamon.

There are no federal guidelines for lead or other heavy metals in spices. New York state has proposed even stricter guidelines than its current level of 1 part per million, which would allow the New York Department of Agriculture and Markets to remove products from commerce if lead levels exceed 0.21 parts per million.

What does it mean that ‘the dose makes the poison’?

The current FDA guideline on daily intake of lead from diets overall is to limit lead intake to 2.2 micrograms per day for children. For women of reproductive age, this value is 8.8 micrograms.

The lead dose we are exposed to from foods depends on the level of lead in the food and how much of that food we eat. Higher doses mean more potential harm. The frequency with which we consume foods – meaning daily versus occasionally – also matters.

For spices like cinnamon, the amount and frequency of consumption depends on cultural traditions and personal preference. For many, cinnamon is a seasonal spice; others use it year-round in savory dishes or sauces.

Cinnamon is beloved in baked goods. Take a cinnamon roll recipe calling for 1.5 tablespoons (slightly less than 12 grams) of the spice. If a recipe yields 12 rolls, each will have around 1 gram of cinnamon. In the Consumer Reports investigation, some cinnamon products were classified as “okay to use” or “best to use.”

The highest value of lead in cinnamon products in the “okay to use” category was 0.87 parts per million, and in the “best to use” category, it was 0.15 parts per million. A child would have to consume 2.5 or more rolls made with the “okay to use” cinnamon to exceed the FDA guideline on limiting lead intake from foods to 2.2 micrograms per day, assuming that no other food contained lead. To exceed this guideline with “best to use” cinnamon, a child would have to eat 15 or more rolls.

Can cinnamon contribute to elevated blood lead levels?

Because of lead’s effects on development in early life, the greatest concern is for exposure in young children and pregnant women. Lead is absorbed in the small intestine, where it can latch onto cellular receptors that evolved to carry iron and other metals.

The impact of a contaminated spice on a person’s blood lead level depends on the dose of exposure and the proportion of lead available for intestinal absorption. For several spices, the proportion of available lead was 49%, which means that about half of the lead that is ingested will be absorbed.

Lead absorption is higher after a fast of three hours or more, and skipping breakfast may contribute to higher blood lead levels in children.

People who have nutritional deficiencies, such as iron deficiency, also tend to absorb more lead and have higher blood lead levels. This is because our bodies compensate for the deficiency by producing more receptors to capture iron from foods. Lead takes advantage of the additional receptors to enter the body. Young children and pregnant women are at higher risk for developing iron deficiency, so there is good reason for vigilance about lead in the foods they consume.

Studies show that among children with lead poisoning in the U.S., contaminated spices were one of several sources of lead exposure. Studies that estimate blood lead levels from statistical models suggest that consuming 5 micrograms of lead or more from spices daily could substantially contribute to elevated blood lead levels.

For occasional or seasonal consumption, or lower levels of contamination, more research is needed to understand how lead in spices would affect lead levels in the blood.

For people who have other sources of lead in their homes, jobs or hobbies, additional lead from foods or spices may matter more because it adds to the cumulative dose from multiple exposure sources.

How to test for elevated blood lead levels

The Centers for Disease Control and Prevention recommends that children at risk for lead exposure get a blood lead test at 1 and 2 years of age. Older children can also get tested. Finger-prick screening tests are often available in pediatric offices, but results may need to be confirmed in venous blood if the screening result was elevated.

Adults in the U.S. are not routinely tested for lead exposure, but concerned couples who plan on having children should talk to their health care providers.

What to consider when using or buying cinnamon or other spices

If the product is on an FDA Alert or the Consumer Reports “don’t use” list, discard it.

Other questions to consider are:

• Does your household use spices frequently and in large amounts?
• Do young children or pregnant women in your household consume spices?
• Do you typically consume spices on breakfast foods or beverages?

If the answer to any of these questions is yes, then buy good-quality products, from large, reputable sellers. Think about using cinnamon sticks if possible.

And continue to enjoy spices!

Katarzyna Kordas, Associate Professor of Epidemiology and Environmental Health, University at Buffalo

This article is republished from The Conversation under a Creative Commons license. Read the original article.