I recently tuned into an intriguing episode of The Daily podcast about ultra-processed food. Health and nutrition reporter Alice Callahan described a surprising experiment conducted by Kevin Hall et al. at the NIH. The goal was to better determine the health effects of a diet high in ultra-processed food. One group of volunteers ate only non-ultra-processed foods for two weeks and another group ate only ultra-processed foods. The two groups then switched. The researchers fastidiously created meals in which the servings of foods provided to each of the two groups were nutritionally identical (same calories, fat, etc.). Participants were able to opt for more servings if they desired. When the results were tallied, participants were found to have gained an average of 2 pounds during their two weeks eating ultra-processed food. They had eaten an average of extra 500 calories per day.
Aside from this arresting result, the episode also delved into some of the history of ultra-processed foods (a term originally coined by a Brazilian scientist named Carlos Monteiro). Loosely defined, a food can be considered ultra-processed if it could not be prepared in a typical kitchen from normally available ingredients. Although these foods made up a substantial portion of the American diet even in the 80's, the purchase of several major food brands by tobacco company such as R.G. Renyolds and Philip Morris led to a related innovation: "hyperpalatable" foods. These foods contain unnatural combinations of common nutrients (e.g., fat, salt, carbohydrates). There is evidence that our brains are especially susceptible to eating these foods to excess. Currently, about 70% of the American diet is now made up of ultra-processed foods and hyperpalatable foods are ubiquitous across brands.
This episode made me think about my own diet. I dropped a portion of the food I typically eat into ChatGPT and asked for an analysis. I eat lots of whole foods which are not ultra-processed but some of the foods I added in the last few years to boost my protein intake were flagged as ultra-processed. Some examples:
Unsweetened soy milk (ultra-processed but low in sugar, high in protein, not hyperpalatable)
Plant-based protein powder (ultra-processed)
Protein bar (ultra-processed, probably hyperpalatable)
I worry more about the food I see my students eating. The meals served in our school cafeteria seem to be largely ultra-processed. Walking around the grocery store recently, I noticed how branding has shifted to highlight protein content (much the way the focus used to be on "low fat"). As we learn more about the ramifications of ultra-processed foods on health, I remember Michael Pollan's succinct recommendation from his book The Omnivore's Dilemma: "eat food, not too much, mostly plants." He wrote about how the "food" in that statement should be something your grandmother or great-grandmother would recognize. In a typical grocery store, the best place to find this in on the periphery of the store. The inner aisles are packed with ultra-processed, hypermarketed pseudo-food. For someone aspiring to a better diet for themselves and/or their family, I think we could do worse than Pollan's simple heuristic, especially in light of Hall's research.
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