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(THE TALK) Vegetarian and vegan options have become standard fare in the American diet, from upscale restaurants to fast-food chains. And many people know that their food choices affect their own health and that of our planet.
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But on a daily basis, it’s hard to know just how much individual decisions, like buying mixed vegetables at the grocery store or ordering chicken wings at a sports bar, can impact overall personal and environmental health. We want to close this gap with our research.
We are part of a research team with expertise in food sustainability and life cycle assessment, epidemiology and environmental health and nutrition. We work to gain a deeper understanding beyond the often oversimplified animal versus plant diet debate and to identify environmentally responsible foods that also benefit human health.
Building on this multidisciplinary expertise, we combined 15 nutritional risk factors with 18 environmental indicators to assess, classify and prioritize more than 5,800 individual foods.
Ultimately, we wanted to know: are drastic dietary changes required to improve our individual health and reduce environmental impact? And does the entire population have to go vegan to make a meaningful difference to human health and that of the planet?
Use hard numbers when choosing food
In our 2021 study, published in the research journal Nature Food, we provide some of the first concrete numbers on the health burden of different food choices. We analyzed each food based on its composition to calculate the net benefits or impact of each food.
The Health Nutritional Index we developed converts this information into minutes of life lost or gained per serving size of each food eaten. For example, we found that eating a hot dog costs a person 36 minutes of “healthy” living. In comparison, we found that consuming a 30 gram serving size of nuts and seeds yielded a 25 minute gain in healthy living – meaning an increase in life expectancy of good quality and disease free.
Our study also showed that replacing as little as 10% of daily caloric intake from beef and processed meats with a diverse mix of whole grains, fruits, vegetables, nuts, legumes, and select seafood could reduce a US consumer’s carbon footprint by an average of around a third and add 48 healthy minutes of life per day. This is a major improvement for such a limited diet change.
How did we crack the numbers?
We base our Health Nutritional Index on a major epidemiological study called the Global Burden of Disease, a comprehensive global study and database developed with the help of more than 7,000 researchers around the world. The Global Burden of Disease determines the risks and benefits associated with multiple environmental, metabolic and behavioral factors – including 15 diet-related risk factors.
Our team took this epidemiological data at the population level and fitted it to the individual food level. Using more than 6,000 risk estimates specific to each age, gender, disease and risk, and the fact that there are approximately half a million minutes a year, we calculated the health burden associated with consuming One gram’s worth of food is associated with each of the dietary risk factors.
For example, we found that for every gram of processed meat a person eats in the US, an average of 0.45 minutes is lost. We then multiplied that number by the corresponding food profiles that we developed earlier. Going back to the hot dog example, the 61 grams of processed meat in a hot dog sandwich results in 27 minutes of healthy life being lost from that amount of processed meat alone. When we then consider the other risk factors like the sodium and trans fats in the hot dog—balanced by the benefits of its polyunsaturated fats and fiber—we came up with a final figure of 36 minutes of healthy life lost per hot dog.
We repeated this calculation for more than 5,800 foods and mixed dishes. We then compared the health index results to 18 different environmental metrics, including carbon footprint, water use, and the impact of air pollution on human health. Finally, using this health and environmental nexus, we color-coded each food item with green, yellow, or red. Like a traffic light, green foods have a positive impact on health and low environmental impact and should be increased in the diet, while red foods should be reduced.
What do we do now?
Our study allowed us to identify certain priority actions people can take to both improve their health and reduce their ecological footprint.
In terms of environmental sustainability, we found notable differences both within and between animal and plant-based foods. Of the “red” foods, beef has the largest carbon footprint over its life cycle – twice that of pork or lamb and four times that of poultry and dairy. From a health perspective, eliminating processed meat and reducing overall sodium consumption offers the greatest gain for healthy living compared to all other food types.
Therefore, people might consider eating less foods high in processed meat and beef, followed by pork and lamb. And, particularly among plant-based foods, greenhouse-grown vegetables fare poorly on environmental impact due to combustion emissions from heating.
Foods that could be considered for consumption are those that have a high positive impact on health and low environmental impact. We’ve seen a great deal of flexibility in making these “green” choices, including whole grains, fruits, vegetables, nuts, legumes, and seafood with a low environmental impact. These items also offer options for all income levels, tastes, and cultures.
Our study also shows that when it comes to the sustainability of food, it is not enough to just look at the amount of greenhouse gases emitted – the so-called carbon footprint. Water-saving techniques like drip irrigation and the reuse of gray water — or domestic wastewater like that from sinks and showers — can also make important steps toward reducing the water footprint of food production.
A limitation of our study is that the epidemiological data do not allow us to differentiate within the same food group, such as B. the health benefits of a watermelon over an apple. In addition, individual foods must always be considered in the context of the individual diet, from the maximum value at which foods are no longer beneficial – you do not live forever with increased fruit consumption.
At the same time, our Health Nutrient Index has the potential to be regularly updated to incorporate new insights and data as they become available. And it can be customized worldwide, as has already happened in Switzerland.
It was heartening to see how small, targeted changes can make such a significant difference in health and environmental sustainability – one meal at a time.
This article was republished by The Conversation under a Creative Commons license. Read the original article here: https://theconversation.com/individual-dietary-choices-can-add-or-take-away-minutes-hours-and-years-of-life-166022.
Licensed as Creative Commons – Attribution, No Derivatives.
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