According to the Centers for Disease Control and Prevention, nearly 40% of US adults were considered to be obese in 2015-2016. Weight gain has been linked to causing diseases such as diabetes, heart disease, and cancers, with most citing overconsumption of ultra-processed foods to be a contributing factor.
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What are ultra-processed foods?
The NOVA food classification system describes ultra-processed food as industrial formulations that are created from food-based substances. They usually contain additives and are manufactured to be convenient and appetizing.
Common examples of ultra-processed foods include fish fingers, chicken nuggets, ready meals, crisps, factory-produced bread products, soda, shelf-stable meat, canned soups, instant noodles, and chocolate, all of which are extremely popular amongst consumers. However, such foods are well-known for their adverse effects.
Ultra-processed foods and autoimmune issues
Celiac disease and type 1 diabetes are two of the most common autoimmune disorders affecting children with a genetic predisposition alongside environmental factors. However, statistics have shown that the prevalence of both conditions has increased and cannot be attributed solely to genetics. In light of this, researchers have argued that these trends may be linked to the consumption of high-processed foods.
Diets high in ultra-processed foods have been found to induce gut pathogens and increase the growth of microorganisms resulting in an inflammatory response and a leaky gut. This has been linked to increasing autoimmunity in children with a genetic predisposition.
Furthermore, the inclusion of food emulsifiers in ultra-processed food may change the composition of the gut microbiota and permeability of the intestine, further increasing the risk of autoimmunity.
Contrastingly, diets high in unprocessed or minimally processed foods have been found to promote gut health and anti-inflammatory responses.
Ultra-processed diet and calorie consumption
Many have argued that the consumption of processed food may be the primary driver of the obesity crisis. Contemporary research has found diets high in processed foods may cause increased calorie consumption and weight gain.
Using a randomized controlled trial, one research team compared calorie intake and weight gain amongst participants eating a diet characterized as unprocessed versus ultra-processed. Despite the diets being matching in terms of the number of calories, salt, fat, sugar, and carbohydrate content, those on the ultra-processed diet consumed more food and gained more weight.
Participants in the study followed either diet for two weeks before swapping. They were given three main meals per day, alongside bottled waters and access to unprocessed or ultra-processed snacks. They were free to consume as much as they’d like, and the researchers measured the quantities consumed.
It was found that when on the ultra-processed diet, participants consumed, on average, 508 more calories per day, resulting in a two pounds weight gain compared to a two-pound weight loss during the two weeks on the unprocessed diet.
Ultra-processed foods and cancer
Researchers investigating the health implications of consuming ultra-processed foods have also found that they may be linked to cancer. The study involving mass surveys followed the dietary habits of over 100,000 people, particularly middle-aged women, for five years on average.
The team examined the consumption of pre-specified ultra-processed food against the prevalence of prostate, breast, and bowel cancer as well as general cancer risks. The study found that a 10% increase in ultra-processed foods was linked to a 12% increase in the risk of developing cancer.
However, the researchers found that those who ate more processed foods were also more likely to exercise less, smoke, and generally consume more calories. These confounding variables may have influenced the results seen.
Ultra-processed foods and mortality
The adverse effects of regular consumption of ultra-processed foods are well established. However, research specifically investigated the impact of diet and mortality found that those who had a higher proportion of daily intake from ultra-processed foods were linked to a higher mortality rate. Researchers followed the diets of over 44,000 French adults for two years.
Of the sample, 15% had diets consisting of ultra-processed foods. The study followed the participants for a further nine years and found that increased mortality in this 15% was linked to cancer and heart disease. It was noted that the development of such diseases might be linked to excess consumption of fats, salt, and sugar.
Hall, K. et al. (2019) Ultra-processed diets cause excess calorie intake and weight gain: An inpatient randomized controlled trial of ad libitum food intake. Cell Metabolism. doi.org/10.1016/j.cmet.2019.05.008.
Thibault, F. et al. (2018). Consumption of ultra-processed foods and cancer risk: results from NutriNet-Sante prospective cohort. BMJ. Doi: https://doi.org/10.1136/bmj.k322
Centers for Disease Control and Prevention (2018). Overweight & Obesity: Adult Obesity Facts. https://www.cdc.gov/obesity/data/adult.html
Schnabel, L. et al. (2019). Association Between Ultraprocessed Food Consumption and Risk of Mortality Among Middle-aged Adults in France. JAMA Internal Medicine. Doi: 10.1001/jamainternmed.2018.7289
Rauber, F. et al. (2018). Ultra-Processed Food Consumption and Chronic Non-Communicable Diseases-Related Dietary Nutrient Profile in the UK (2008 -2014). Nutrients. Doi: 10.3390/nu10050587
Aguago-Patron, S. V. et al. (2017). Old Fashioned vs. Ultra-Processed-Based Current Diets: Possible Implication in the Increased Susceptibility to Type 1 Diabetes and Celiac Disease in Childhood. Foods. Doi: 10.3390/foods6110100