How heat waves increase your thirst for soda: Mexican results

In June, the unusually warm weather hit Europe, giving residents and visitors a taste of what might become common in the near future. With climate change underway, temperatures are expected to increase by 0.3 to 0.7 ° C by 2035, according to the IPCC.

For policymakers, it is essential to understand how the changing climate of our planet could affect the food and drink that humans consume. Until now, much of the research focused on agricultural productivity – for example, the impact of higher temperatures on crop yields during a growing season – our research at come to Mexico also show that the eating habits of families have also changed weather.

Better understanding if and how consumers respond to rising temperatures may help mitigate the potentially negative consequences of unhealthy diets.

The powerful channel "Cravings"

Warm weather influences dietary patterns through two main channels. The first is physiological: as the thermometer climbs and we begin to sweat, our body encourages us to drink more water to replace lost fluids and regulate body temperature. From a physiological point of view, there is no reason for humans to drink a liquid other than water in response to high temperatures.

But we can not ignore the powerful channel "Cravings". Extensive research has shown that salty snacks and sugary drinks share certain characteristics with addictive products such as tobacco. This suggests that when the temperature rises, some people may feel an irresistible urge to satisfy their thirst, not with water, but with sugary drinks.

According to our research, people who prefer sweetened beverages are more likely to give in to their urge to smoke during heat waves. Since exercise rates decline as temperatures rise, it seems unlikely that the extra sugar consumed will be offset by increased physical activity. The end result will be more calories consumed and possibly weight gain.

Obesity and health

Levels of obesity have been increasing worldwide for decades. In 1975, the average rate was 11.1% in North America and Europe and by 2016 it had more than doubled. In the United States, the average rate for all adults was 37% in 2014, with rates still higher for some ethnic groups. Overweight and obesity can cause various diseases, including heart problems, diabetes and some types of cancer. These, in turn, impose a heavy economic burden on society, particularly with respect to health expenditures that add financial pressure to health systems.

In addition to the countries of North and South America, Australasia and Western Europe, Mexico has an average consumption of sugary drinks well above the recommended 50 grams of sugar per day recommended by the World Health Organization (about 10 teaspoons). Direct result: This country has the second highest obesity rate of the OECD countries.

How the weather influences consumption habits

Mexico is located near the equator, which makes it vulnerable to severe weather variations. Temperatures can reach nearly 50 ° C (122 ° F) and heat waves have become more frequent in recent years.

In our research, we combined survey data on the daily food expenditure of some 85,000 Mexican households with weather data on the daily outdoor temperatures of the Mexican National Water Commission (CONAGUA). The survey includes logbooks on daily food consumption and spending on a week for each household and each wave of survey (2008, 2010, 2012 and 2014) (Encuesta Nacional de Ingresos and Gastos de losHogares)

Given the short period of study, our estimates do not take into account changes in food production and therefore time-induced food supply. As a result, our results provide information on short-term consumer responses to rising temperatures without changing the food products on offer. We also compared food purchasing behaviors in the same municipality during cooler, warmer days. Using this approach, we were able to exclude behavioral differences due to varying conditions across municipalities, such as different climate zones or variations in available food products and prices.

Our results show that Mexican consumers increase their consumption of soda and juice by about 20% in weeks where the daily temperature exceeds 32 ° C (90 ° F) compared to days when the temperature is below 22 ° C (72 ° F). At the same time, we have not seen a significant increase in water consumption, itself significant given that fountains and other public sources of free drinking water are not not frequently available in Mexico.

These results support the "cravings" channel hypothesis, suggesting that people with a preference for sugary drinks have more difficulty withstanding rising temperatures. We further document that these responses to consumption translate into slightly higher body mbad index (BMI) levels, particularly among young women.

Is more information sufficient?

A range of public policy approaches aimed at reducing the consumption of sugary drinks on hot days is possible. Mexico has already taken steps to inform consumers of the health risks badociated with it, and our findings indicate that they can be effective if they are deployed just before or during the months of the year. summer. Weather forecasts on television and on the Internet could also be accompanied by short messages reminding people to drink water rather than sodas.

Another approach is to make sugary drinks more expensive than healthier alternatives, especially water. In 2014, Mexico introduced a sugar tax, and preliminary results indicate that sales of beverages have declined moderately. Authorities may also limit sales in certain areas, such as nearby schools or during certain periods.

Fountains or other sources of drinking water are also needed in public areas. They would offer consumers a free and healthy alternative to buying a sweet drink.

A more radical approach would simply be to ban sweetened beverages during the summer for public health reasons. This is similar to the ban on outdoor fires to reduce the risk of forest fires. The soft drink and fast food sector has always lobbied to block local regulation of their products and it remains to be seen whether policy makers will be able to implement such an ambitious approach.

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