The increasingly unhealthy diet is not only bad for human health directly but is causing environmental damage to the planet


A global diet that increasingly includes ultra-processed foods is having a negative impact on the diversity of plant species available for human consumption while also damaging human and planetary health, according to a commentary published in the journal BMJ Global Health.

Experts are warning that an increasingly unhealthy diet is not only bad for human health directly but is causing environmental damage to the planet.

Ultra-processed foods such as sweetened or salty snacks, soft drinks, instant noodles, reconstituted meat products, pre-prepared pizza and pasta dishes, biscuits and confectionery, are made by assembling food substances, mostly commodity ingredients, and ‘cosmetic’ additives (notably flavors, colors and emulsifiers) through a series of industrial processes.

These products are the basis of a ‘globalized diet’ and are becoming dominant in the global food supply, with sales and consumption growing in all regions and almost all countries. Currently, their consumption is growing fastest in upper-middle-income and lower-middle income countries.

Consequently, dietary patterns worldwide are becoming increasingly more processed and less diverse, having an impact on agrobiodiversity – the variety and variability of animals, plants and microorganisms used directly or indirectly for food and agriculture.

Nutrition experts from Brazil, the US and Australia have written a commentary after investigating the issue.

They said that the bad effects of ultra-processed foods on human health were well documented, but there was still low awareness of their damaging impact on planetary health, and ultra-processed foods were missing from international development agendas.

They warned that global agrobiodiversity was declining, especially the genetic diversity of plants used for human consumption.

More than 7,000 edible plant species are used for human food, but fewer than 200 species had significant production in 2014, and just nine crops accounted for more than 66% by weight of all crop production.

As much as 90% of humanity’s energy intake comes from just 15 crop plants, and more than four billion people rely on just three of them – rice, wheat and maize.

The authors warned that such a decline in biological diversity in food systems was disrupting and damaging biospheric processes and ecosystems that supported reliable and sustainable food production, reduced diet diversity and created a barrier to healthy, resilient and sustainable food systems.

They pointed to an ongoing study of 7,020 ultra-processed foods sold in the main Brazilian supermarket chains which had found that their five main ingredients included food substances derived from sugar cane (52.4%), milk (29.2%), wheat (27.7%), corn (10.7%) and soy (8.3%).

As a result, peoples’ diets were less diverse, with ultra-processed foods replacing the variety of wholefoods necessary for a balanced and healthy diet.

Production of ultra-processed foods involved greater use of ingredients extracted from a handful of high-yielding plant species (such as maize, wheat, soy and oil seed crops) which meant that animal-sourced ingredients used in many ultra-processed foods were often derived from confined animals fed on the same crops.

Another issue of concern was that ultra-processed food production used large quantities of land, water, energy, herbicides and fertilizers, causing environmental degradation from greenhouse gas emissions and accumulation of packaging waste.

The authors concluded: “The very rapid rise of ultra-processed foods in human diets will continue to place pressure on the diversity of plant species available for human consumption.

“Future global food systems fora, biodiversity conventions and climate change conferences need to highlight the destruction of agrobiodiversity caused by ultra-processed foods, and to agree on policies and actions designed to slow and reverse this disaster.

“Relevant policy makers at all levels, researchers, professional and civil society organizations, and citizen action groups, need to be part of this process.”

Based on the analysis of data collected by two 24-hour food records in a probabilistic sample of the Brazilian population aged 10 years and over (n = 32,886), we found a significant linear association between the dietary contribution of the ultra-processed food group and the diet water footprint, even after adjusting for potential sociodemographic confounders. As far as we know, this is the first nationally representative study to show a negative environmental effect of consuming ultra-processed foods. The same linear association shown for the diet carbon footprint in the crude analysis was no longer significant after adjusting for the same sociodemographic variables.

Our results also showed that the additional adjustment for energy intake eliminated the association between the dietary contribution of ultra-processed foods and the diet water footprint, indicating the mediating role of total energy intake in that association.

The dietary contribution of ultra-processed foods was positively associated with the diet water footprint despite the lower water footprint of ultra-processed foods. This smaller footprint, apparently due to the smaller share of the meat subgroup in the ultra-processed group, failed to compensate for the higher total energy intake associated with the consumption of these foods. In any case, our results have shown that the association between the consumption of ultra-processed foods and diet environmental footprints cannot be predicted solely by comparing coefficients of the environmental impact of ultra-processed and non-ultra-processed foods, as it is sometimes done25.

Although we only evaluated two dimensions of the diet environmental impact in our study, the evidence that the consumption of ultra-processed foods increases the diet water footprint in Brazil, remaining neutral regarding the carbon footprint, adds to the evidence showing the negative effects of ultra-processed foods on the quality of the Brazilian diet26 and on the risk of several non-communicable diseases in the Brazilian population27. This reinforces the recommendation of the Brazilian Dietary Guidelines to avoid the consumption of ultra-processed foods10.

Given that the impact of the dietary contribution of ultra-processed food on diet environmental footprints depends on the footprints per energy of the ultra-processed and non-ultra-processed fractions of the diet, which, in turn, depend on the profile of ultra-processed and non-ultra-processed foods consumed by the population, the results of our study cannot be extrapolated to countries with considerably different dietary patterns to those of Brazil.

As indicated in our study, the proportion of meat products in the ultra-processed fraction of the diet is particularly important: when this proportion is lower than that observed in the non-ultra-processed fraction, as in the Brazilian diet, increases in the dietary share of ultra-processed foods are less likely to increase the diet environmental footprints. Another relevant factor is the relationship between the consumption of ultra-processed foods and the total energy intake: when this relationship is positive, as in the Brazilian diet and often observed in other countries’ diets6, increases in the dietary share of ultra-processed foods are likely to increase dietary environmental footprints. Thus, carrying out new studies on the effects of ultra-processed foods on dietary environmental footprints in countries with dietary patterns different from Brazil, in particular those with the highest consumption of ultra-processed foods, is important. Studies should also be carried out in countries that have already adopted the recommendation to limit or to avoid the consumption of ultra-processed foods in their dietary guidelines10, or are considering doing so.

A strength of our study is the assessment of the environmental impact of ultra-processed foods as actually consumed by the population. We were able to consider the mix of varieties of ultra-processed foods that are part of the diet, changes in this mix with variations in the dietary contribution of ultra-processed foods, and simultaneous changes in the varieties of non-ultra-processed foods. Other strengths are the representative sample of the population, the objective measurement of the participants’ diet based on two 24-hour food records, and the use of environmental impact coefficients that consider the entire life cycle of foods, from ‘farm to fork’.

A limitation is the assessment of only two environmental footprints of diet, not including, for example, impact on agrobiodiversity and the generation of solid waste from packaging. Also, the table of environmental impact coefficients used in the study, includes estimates from studies carried out in countries other than Brazil, and reports prepared by the industry, and not from independent studies.

reference link :

More information: Ultra-processed foods should be central to global food systems dialogue and action on biodiversity, BMJ Global Health (2022). DOI: 10.1136/bmjgh-2021-008269


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