The Wellness Brew - Issue 10

The modern grocery store is unrecognizable compared to what it once was. Roughly 70% of products on the shelves of an average American supermarket are ultra-processed, formulated to be cheaper, more shelf-stable, and harder to stop eating than what came before. The category barely existed two generations ago. Today it makes up more than half of the calories the average adult consumes. This week's Deep Dive examines what the evidence now shows about ultra-processed foods, how to recognize them on a label, and where the highest-leverage changes are for anyone trying to eat differently.

But first, we filtered the noise — here's what's worth knowing this week.

Bryan Johnson's microplastic claim, and the protocols underneath it

Bryan Johnson, the longevity influencer behind the "Don't Die" protocol and one of the most prolific self-experimenters in the space, claimed to be the first person ever to record zero microplastics in his semen, down from 165 particles per milliliter eighteen months earlier. The protocols Johnson used to reduce the microplastics in his body are easily replicable and worth considering. The three primary interventions were regular dry sauna use, a reverse osmosis water filtration system, and the removal of plastic from his food environment, specifically plastic cutting boards, food storage containers, non-stick cookware, and microwaving food in plastic. He could not isolate which intervention drove the result or whether all three contributed. The reverse osmosis and plastic-removal interventions are well-supported in the research. The sauna piece is more contested, though saunas have other documented health benefits. Johnson's n=1 self-experiment is not evidence in the scientific sense, but for a problem as pervasive and difficult to escape as microplastic exposure, it is encouraging to see that meaningful reduction may be possible at all. 

Food additives have historically been evaluated for safety individually. The trouble is that nobody eats them one at a time. A 2025 study in PLOS Medicine, drawn from the French NutriNet-Santé cohort of more than 108,000 adults, examined how additives are actually consumed and tracked which combinations were associated with the development of type 2 diabetes over a follow-up averaging 7.7 years. Two of the five most common additive combinations in the French diet showed elevated risk. The first was a blend of emulsifiers and stabilizers including modified starches, pectin, guar gum, carrageenan, and xanthan gum, typically found in stocks, milky desserts, fats, and sauces. The second was a combination of artificial sweeteners, food colorings, and acidifiers, characteristic of diet sodas and artificially sweetened beverages. Substance-by-substance safety testing systematically misses combination effects. The takeaway — check ingredient labels for common emulsifiers and avoid drinking diet soda regularly. Payen de la Garanderie et al., PLOS Medicine, 2025.

Roughly 55% of the calories the average American eats now come from ultra-processed foods. Among children and teenagers the figure is 62%. Two generations ago, the category as we know it barely existed. This is the single largest dietary shift in modern history, and almost no one made an active decision to participate in it. It happened by default, one product at a time, as the shelves filled with foods engineered to be cheaper, more shelf-stable, and harder to stop eating than what came before.

The evidence on what this shift is doing to long-term health is now substantial enough that the question has moved from whether ultra-processed foods harm health to how much, in which ways, and what to do about it.

The term "ultra-processed food" comes from the NOVA classification system, developed by researchers at the University of São Paulo and now used across the major nutrition journals.[2] NOVA sorts foods into four groups based on how they are made, not what they contain.

Group 1 is unprocessed or minimally processed foods. Fruits, vegetables, eggs, meat, fish, milk, dried beans, plain yogurt, oats. Group 2 is culinary ingredients used to prepare them. Salt, oil, butter, vinegar. Group 3 is processed foods, made by combining the first two groups. Bread baked with flour, water, salt, and yeast. Canned tomatoes. Cheese.

Group 4, ultra-processed, is the category that has expanded most over the past fifty years. These are industrially manufactured products typically containing five or more ingredients, often including substances rarely found in home kitchens. Emulsifiers, modified starches, hydrogenated oils, protein isolates, flavorings, colorings, and preservatives. The defining feature is that they are formulations of ingredients, not foods that have been prepared from ingredients.

The distinction matters because not every packaged food is ultra-processed. A loaf of sourdough with four ingredients is not the same as a protein bar with thirty. Greek yogurt with one ingredient is not the same as a flavored yogurt with twelve. The point of NOVA is to draw that line clearly.

The most comprehensive synthesis to date is a 2024 umbrella review published in The BMJ that pooled 45 separate meta-analyses covering 9.9 million participants. The review found direct associations between ultra-processed food consumption and 32 of 45 health parameters examined, including all-cause mortality, cardiovascular mortality, type 2 diabetes, cancer, depression, anxiety, and adverse sleep outcomes.[3]

A 2025 systematic review and dose-response meta-analysis of 18 prospective cohort studies involving 1.1 million participants found that people in the highest tier of ultra-processed food intake had a 15% increased risk of all-cause mortality compared to those in the lowest tier. The risk rose incrementally with every additional 10% of the diet made up of these products.[4]

A 2025 systematic review presented at the American College of Cardiology Asia Scientific Session found that each additional 100 grams per day of ultra-processed food was associated with a 14.5% higher risk of hypertension, a 5.9% increased risk of cardiovascular events, and a 19.5% higher risk of digestive diseases.[5] These are observational findings and cannot prove causation on their own, but they are remarkably consistent in direction and magnitude across study designs, populations, and decades.

The metabolic data is equally striking. A prospective cohort study of more than 104,000 adults published in JAMA Internal Medicine found that a 10% absolute increase in the share of ultra-processed food in the diet was associated with a 15% higher risk of developing type 2 diabetes, independent of overall nutritional quality. The effect held after adjusting for body weight, sugar intake, sodium, and fiber, suggesting that something about the ingredients or the processing itself, not just the calories, drives the risk.[6]

The mental health signal is now equally well established. A 2023 analysis published in JAMA Network Open followed more than 31,000 women over the course of a decade and found that those in the highest tier of ultra-processed food intake had a 50% higher risk of clinically diagnosed depression than those in the lowest tier. Artificially sweetened beverages and artificial sweeteners themselves were identified as the strongest single drivers of the association, more so than refined sugars or processed meats.[7]

One clarifying point. There is no specific intake level below which ultra-processed foods are safe and above which they are dangerous. The risk rises proportionally with the percentage of total calories these products make up. Reducing consumption, even partially, appears to lower risk.

The reasons ultra-processed foods affect health differently from minimally processed foods are now reasonably well understood. Four pathways stand out.

Hyperpalatability and overconsumption. The strongest causal evidence comes from a 2019 inpatient feeding trial conducted at the NIH by Kevin Hall and colleagues. Twenty adults were housed in a metabolic ward and given two diets for two weeks each. One diet was built from ultra-processed foods, the other from minimally processed foods. The two diets were designed to be equivalent on paper, matched in available calories, fat, sugar, sodium, fiber, and protein percentages. Participants were told to eat as much or as little as they wanted at every meal. On the ultra-processed diet, they ate roughly 500 more calories per day and gained an average of two pounds over the two-week period. On the minimally processed diet, they lost weight.[8] The sample was small, which means the effect size should be interpreted carefully, but as the only inpatient randomized controlled trial of its kind, it remains a foundational piece of evidence. The way these foods are engineered appears to drive passive overconsumption, even when the nutritional profile looks identical on a label.

Specific additives that disrupt the gut. A randomized controlled trial published in Gastroenterology in 2022 showed that the emulsifier carboxymethylcellulose, found widely in non-dairy milks, baked goods, salad dressings, and ice cream, measurably altered the gut microbiome and reduced short-chain fatty acid production after just eleven days of consumption at typical dietary levels.[9] Other emulsifiers including polysorbate-80, carrageenan, and mono- and diglycerides have shown similar effects across animal and human studies, with a 2023 cohort analysis linking higher intake to elevated cardiovascular disease risk.[10]

Glucose volatility and metabolic stress. Refined carbohydrates and added sugars, which appear in the majority of ultra-processed products, drive rapid post-meal glucose spikes and crashes. Repeated daily, this pattern contributes to insulin resistance, visceral fat accumulation, and the slow drift toward type 2 diabetes that defines so much of modern metabolic disease. This relationship now shows up across multiple large prospective cohorts independent of overall diet quality.[6]

The loss of the food matrix. Nutrients in their original food structure behave differently than the same nutrients extracted, refined, and reassembled. Whole almonds and almond flour, whole oranges and orange juice, whole grains and refined flour are not nutritionally equivalent even when the macronutrient profiles look similar on a label. The matrix affects how quickly nutrients are absorbed, how full a person feels, and how the body responds metabolically.[11]

Several ingredients consistently flag a product as ultra-processed. Recognizing them is one of the highest-leverage habits a person can build at the grocery store.

Refined sugars travel under many names: high-fructose corn syrup, dextrose, maltodextrin, evaporated cane juice, brown rice syrup, cane syrup. If three or four of these appear in one product, that product is engineered around sweetness.

Industrial seed oils (canola, soybean, sunflower, corn, cottonseed, safflower) are not as significant a concern as most influencers make them out to be, and the evidence on direct cardiovascular harm is contested. That said, they are heavily processed, and their presence in a packaged food is one of the most reliable signals that the product is ultra-processed, because these oils are the cheapest cooking fats available at industrial scale.

Emulsifiers and stabilizers. Carboxymethylcellulose (sometimes labeled as cellulose gum), polysorbate-80, carrageenan, and mono- and diglycerides are the four with the strongest evidence of gut disruption. They appear in non-dairy milks, ice cream, salad dressings, packaged bread, plant-based meat alternatives, and coffee creamers.

Umbrella terms. "Natural flavors" and "fragrance" can each legally represent a proprietary blend of dozens to hundreds of individual compounds, none of which must be disclosed.

Artificial sweeteners. In 2023 the World Health Organization issued guidance recommending against the use of non-sugar sweeteners for weight management, citing a systematic review linking long-term consumption to elevated risk of type 2 diabetes, cardiovascular events, and earlier all-cause mortality.[12] Occasional use is not the concern. Daily use in coffee, protein bars, and diet beverages is.

Telling someone to avoid ultra-processed foods is not particularly useful advice. They make up most of the supermarket. They dominate restaurant menus. They are cheaper, more available, and easier to eat than the alternatives. The more useful framing is not avoidance but substitution, one category at a time, until the baseline of what is in the house has quietly shifted. The actionable takeaways below are where to start.

Four things you can do this week:

1. Run the five-second label scan. Before any packaged item goes in the cart, read the first three ingredients. If any of the first three are refined sugar, an industrial seed oil, or an emulsifier (cellulose gum, polysorbate-80, carrageenan, mono- and diglycerides), put it back. If there are more than 5 ingredients total, it’s almost always ultra-processed. This single habit takes a few seconds and changes what comes home from the store.

2. Shop the outer aisles first. The perimeter of nearly every supermarket holds the whole foods: produce, meat, fish, dairy, eggs. Build the cart there before stepping into the inner aisles. The inner aisles are not off-limits, but they require the label scan above. The perimeter generally does not.

3. Cook one more meal at home this week than last week. The single largest variable in ultra-processed food intake is meal source. Restaurant meals, fast food, and takeout are built on industrial seed oils, refined sugars, and ultra-processed components by default. Adding one home-cooked meal per week is one of the highest-leverage changes available, and over a year that is fifty-two more meals that you control.

4. Replace one category at a time. Trying to overhaul a kitchen in a weekend rarely sticks. Pick one category and upgrade it before moving to the next. Cooking oil in week one. Bread in week two. Dairy in week three. Within two months the staples in the kitchen look different, and the change holds because each swap had time to become normal.

To see the full framework we use for thinking about food, plus a system that makes the changes stick, The Clean Grocery Guide e-book is now live and free for all subscribers. Download it here!

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The Wellness Brew

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Disclaimer: The Wellness Brew is for informational purposes only and does not constitute medical advice. The content published here is not intended to diagnose, treat, cure, or prevent any disease or health condition. Always consult a qualified healthcare professional before making any changes to your diet, supplement routine, or lifestyle.