Welcome to the first edition of Tischbusters, where we tackle common nutrition myths and buzzwords to uncover the science behind what we eat. With so much nutrition advice out there—some of it misleading or outdated—it’s time to set the record straight.
In this inaugural article, we explore the truth about ultra-processed foods, work to define and classify them, and ultimately answer pressing questions. Are ultra-processed foods as harmful as they’re made out to be? Can they fit into a health-promoting diet?
With insights from our team of researchers and dietitians, we’re here to separate fact from fiction and help you make informed, evidence-based decisions about your health.
Ultra-Processed Food and Health
Written by Catalina Duque Jaramillo, Oliver Gonzalez-Yoakum, Christine Torressen, and Wency Xiang
Researched by Catalina Duque Jaramillo, Chelsea Dyapa, Alison Garbarini, Thu Thu May Oo, and Malik Tiedt
Ultra-Processed Foods (UPFs) are one of those things that we all know but can’t quite define.
Cheetos? For sure a UPF.
Granola bars? Maybe?
Bread? Hmm…
To overcome the challenge of classifying foods and defining UPFs, the NOVA system proposes a 4 food group categorization ranked according to the degree and purpose of their industrial processing (Monteiro et al., 2019). While some processing is necessary to transform raw foods into a variety of food products (think olive oil, cheese, or jam), UPFs are further processed and industrially produced with a focus on hyperpalability and convenience. UPFs are primarily composed of extracted and chemically modified food substances, enriched with additives, and contain minimal whole foods. They possess substantial quantities of sugar, salt, oils, and fats and frequently employ techniques that do not have a corresponding method used domestically, such as high-temperature extrusion and molding. Their distinctiveness from other NOVA groups is their utilization of substances produced from infrequently employed food sources in culinary practices, such as protein isolates, hydrogenated oils, and modified starches (Monteiro et al., 2024). Some examples of UPFs are soft drinks, chips, chocolate, candy, ice cream, sweetened breakfast cereals, packaged soups, chicken nuggets, hotdogs, and fries.
When defining UPFs, it is first important to acknowledge that numerous industrial operations are essential or advantageous for maintaining one's health. These include machines or processes that convert raw foods into minimally processed foods, classified as NOVA group 1 (e.g., fruit, vegetables, eggs, meat, milk). The extract of processed culinary ingredients from group 1 foods using equipment and other methods such as plant oils, animal fats (e.g., butter), sugar, syrup, honey, starch, and salt falls under NOVA group 2. The processes used to modify group 1 foods, such as those used in making traditional bread, jams, and cheeses, are categorized as NOVA group 3. The final 4th NOVA group is the ultra-processed foods (UPFs) group. NOVA group 4 consists of foods mainly composed of inexpensive industrial sources of dietary energy and nutrients, together with additives, and contain very little, if any, whole food. They possess substantial quantities of sugar, salt, oils, and fats and frequently employ techniques that do not have a corresponding method used domestically, such as high-temperature extrusion and molding. Their distinctiveness from other NOVA groups is their utilization of substances produced from infrequently employed food sources in culinary practices, such as protein isolates, hydrogenated oils, and modified starches. Their utilization of flavors, colors, emulsifiers, and other cosmetic additives is intended to conceal the fundamental constituents and enhance the appeal of the end product to the senses (Monteiro et al., 2019). Some examples of UPFs are soft drinks, chips, chocolate, candy, ice cream, sweetened breakfast cereals, packaged soups, chicken nuggets, hotdogs, and fries.
Numerous studies have investigated the association between UPFs and health, revealing a link between higher consumption of UPFs and increased risks of noncommunicable chronic diseases (e.g., type 2 diabetes, cancers, etc.) (Fiolet et al., 2018; Jardim et al., 2021; Zhang & Giovannucci, 2022), cardiovascular events (Zhang & Giovannucci, 2022), weight gain (De Amicis et al., 2022; Crimarco et al., 2021; Hall et al., 2019; Zhang & Giovannucci, 2022), increased all-cause mortality (Crimarco et al., 2021; Zhang & Giovannucci, 2022), and decreased cognitive function (Gomes Gonçalves et al., 2022).
While the vast majority of studies on UPFs are observational studies, there has been an increasing number of experimental studies. For example, the study by Hall et al. in 2019 was the first randomized controlled trial to demonstrate causality: a high proportion of UPFs increases energy intake and leads to weight gain. Specifically, UPFs mess with our hunger and satiety cues causing us to overeat and gain more weight. According to the findings of Hall et al., removing ultra-processed foods from the diet lowers energy intake and causes weight loss, whereas consuming a diet high in ultra-processed foods raises energy intake (by about 500 calories per day) and causes weight gain. The most typical differences observed between ultra-processed (UP) versus unprocessed diets were the energy intake and sugar, fat, and sodium content. Results showed greater fat consumption in all 3 meals during the UP diet. Further, participants gained body fat mass (with less fat oxidation) and fat-free mass (with an increase in body fluids) and had slightly higher daily glucose levels. Conversely, when compared to the ultra-processed and baseline diets, a few factors benefited from increases and decreases during the unprocessed diet: ghrelin (the hunger hormone), adiponectin, total cholesterol, and T3 decreased, and leptin (the appetite-suppressing hormone), PYY, T4, and free fatty acids increased.
The findings underscore a potential mechanism by which UPFs contribute to obesity and poor metabolic health, by promoting excess calorie intake and disrupting normal leptin signaling pathways. The advice to consume a diet low in UPFs may be adopted by many different healthful eating strategies, such as plant-based, low-fat, low-carb, or animal-based diets (Hall et al., 2019).
Overall, reducing the amount of UPFs in diets can help prevent the development of various diseases and promote well-being. However, UPFs are incredibly inexpensive, shelf-stable, and transportable. They are palatable and easily accepted by finicky eaters. For many families, UPFs can mean the difference between going to bed satiated and hungry and, for growing bodies and minds, any kind of nourishment is better than none.
We believe that UPFs can have a place in a health-promoting diet. While they should not form the backbone of a diet pattern, ultra-processed foods may have a small place in an otherwise health-promoting, whole-foods, plant-forward diet pattern!