Researchers found that rising temperatures in the U.S. are driving higher consumption of added sugars, mainly from sodas and frozen desserts. The effect is strongest among low-income and less-educated households, raising health risks as climate change intensifies.
Study: Rising temperatures increase added sugar intake disproportionately in disadvantaged groups in the USA. Image credit: Dev_Maryna/Shutterstock.com
A new study published in Nature Climate Change reports that the global rise in environmental temperature has disproportionately increased added sugar consumption in U.S. households with lower socioeconomic status or educational levels.
Background
Climate change's worldwide changes in temperature and rainfall patterns can potentially affect individuals' dietary patterns by altering crop production, crop nutrient content, seafood abundance and distribution, and livestock health and productivity.
Extreme weather conditions can substantially alter dietary demands, which in turn can lead to nutrition-related diseases. Hot weather, for instance, often drives individuals to consume chilled or frozen beverages for hydration. These beverages contain high amounts of added sugar, which can negatively impact health.
Several studies have highlighted negative health consequences of consuming excessive added sugar, including obesity, diabetes, metabolic syndrome, cardiovascular disease, and certain cancers.
The dietary guidelines for Americans recommend restricting added sugar intake to less than 10% of daily calories. The American Heart Association recommends even lower limits: 24 grams for women and 36 grams for men. However, existing evidence indicates that average intake in the U.S. is above recommended thresholds, with vulnerable groups already far exceeding them.
The current study aimed to investigate the effect of extreme weather conditions on added sugar intake across socioeconomically diverse populations in the USA between 2004 and 2019. The study analyzed individual-level food purchase data from 40,000–60,000 US households to determine each household's added sugar intake.
Key findings
The study findings revealed that added sugar intake increases with rising temperature. The increase was mild at temperatures below 10 °C and 12 °C, followed by a sharp increase between 12 °C and 30 °C. The intake slowed or plateaued above 30 °C, though the authors caution that this result is based on very limited data (only 0.8% of observations at such temperatures).
Among other tested weather conditions, wind speed significantly negatively impacted added sugar intake, while rainfall had a positive impact.
Among various food items with added sugar, sweetened beverages increased sharply between 12 °C and 30 °C, while frozen desserts increased relatively slowly. Added sugar intake from bakery products, oils, and raw sugars slightly decreased with rising temperature, indicating a potential substitution towards more chilled, hydrating items.
Notably, the study found significant disparities in added sugar intake across households with different socioeconomic backgrounds. The impact of temperature on added sugar intake was much stronger in households with lower socioeconomic status or lower educational attainment compared to households with higher educational levels or higher income. The researchers also observed differences by ethnicity and work environment; for example, Asian households showed no significant response, and those working outdoors were more sensitive to temperature changes.
The study conducted simulation analyses to predict changes in added sugar intakes under future climatic conditions. The simulations, based on an overall temperature increase of 5 °C from 2019 to 2095, indicated that daily added sugar intake may increase by about 3 grams per person (with an estimated range of 1.4 – 4.6 grams, depending on climate model), with larger increases projected for northern U.S. regions and in summer and autumn.
Study significance
The study finds that the added sugar intake rate in the USA increases with rising temperature, especially between 12 °C and 30 °C. The intake rate tends to decline at temperatures above 30 °C, likely due to physiological responses, such as appetite suppression, though this remains uncertain due to sparse data at extreme heat levels.
The study identifies sugar-sweetened beverages, such as soda and juice, and frozen desserts, such as ice cream and gelato, as the main contributors to increased added sugar intake. The real-world scenarios evidenced in the study, and the projections made by the study, indicate that the impact of temperature on added sugar intake is much stronger in households with poor socioeconomic status or lower educational levels.
The lower responsiveness of high-income populations to weather changes may be associated with their experience of different micro-environmental temperatures, particularly at workplaces. The financial ability of these populations to opt for healthier food and drink choices out of health concerns may also justify their lower intakes of added sugar.
The average daily intake of added sugar in vulnerable low-income populations already exceeds 10% of the recommendations from the 2015–2020 Dietary Guidelines for Americans and almost 20% of the recommendations from the American Heart Association. Given such over-intake, the current study highlights the need to control nutrition and health inequalities exacerbated by climate change, possibly by identifying key populations and developing targeted interventions.
The study also highlights the need for developing more robust policies to reduce added sugar intake, especially in sugar-sweetened beverages. Taxation on such beverages has been an effective approach to reducing the purchase rate in some US cities. However, nationwide implementation of such taxes could face crucial challenges and delays.
Increasing public awareness about the negative health consequences of consuming added sugar could be a helpful approach. This can be achieved through continuous nutritional education programs and the introduction of nutrition warning labels on food products containing high levels of added sugar. An increased awareness among consumers may potentially force industries to respond by reformulating products to reduce the sugar content in beverages.
Importantly, the authors note that while the study is U.S.-focused, the findings have broader global relevance, since similar climate-driven dietary shifts are likely in other countries such as Brazil, South Africa, and Mexico.
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