Ultra-Processed Meals and Insulin: What a New Study Found

Your blood sugar reading after a meal doesn’t tell you how hard your body worked to produce it. A new study found that two meals with the same calories, carbs, fat, protein, fiber and glycemic index gave very similar blood sugar peaks, but the ultra-processed meal pushed insulin higher and kept it up longer.^[1] Here’s what that means, what it doesn’t, and what to do about it this week.

What the study tested

Researchers at Virginia Tech asked a clean question: if you match the nutrients, does the level of food processing still change how your body responds? They enrolled 57 healthy-weight adults (average age 26, average BMI 22.75), and 32 of them completed both metabolic sessions. On separate mornings, after an overnight fast, each person ate a roughly 300-calorie meal in under 10 minutes. One meal was ultra-processed. The other was not.^[1]

The meals matched within 1.6% on weight, energy, macronutrients, available carbohydrate, glycemic index and load, fiber and sodium. “Ultra-processed” here follows the Nova system, which flags industrially made products with added ingredients and additives you wouldn’t use in a home kitchen. For three hours afterward, participants stayed in a room-sized calorimeter that measured how much energy they burned, while a catheter collected blood samples.^[1] Because every person ate both meals, each one served as their own comparison.

What it found: blood sugar matched, insulin didn’t

Blood sugar was not the story. Glucose over the three hours was statistically the same after both meals, and it was actually higher at the 20-minute mark after the minimally processed meal.^[1] If you’ve seen headlines saying ultra-processed food kept blood sugar elevated in this study, they go further than the data. Overall glucose exposure was the same; the paper notes only a non-significant trend toward higher glucose at 120 and 180 minutes after the ultra-processed meal.^[1]

Insulin told a different story. Insulin exposure over time was greater after the ultra-processed meal. The two meals looked alike at 5 and 20 minutes, but insulin was higher after the ultra-processed meal at 40, 60, 90 and 120 minutes, and both returned to near baseline by 180 minutes.^[1] The ultra-processed meal also produced a bigger overall energy burn, and the authors reported an attenuated carbohydrate oxidation response compared with the minimally processed meal.^[1]

The practical takeaway: in this study, a normal-looking glucose reading sat on top of a bigger insulin response. A finger stick or a glucose sensor shows you the first and not the second.

Why higher insulin matters, and where the evidence stops

Insulin moves sugar out of your blood and into your cells. If your cells keep getting asked to respond to high insulin, they can respond less over time, a state called insulin resistance. We covered the blood sugar side of that in why a normal HbA1c can hide metabolic stress.

Here’s the link to ultra-processed food and diabetes risk, and it comes from a different kind of evidence. In three large US cohorts (Nurses’ Health Study, Nurses’ Health Study II and the Health Professionals Follow-Up Study) with 19,503 type 2 diabetes cases, people in the highest fifth of ultra-processed food intake had a hazard ratio of 1.46 (95% CI 1.39 to 1.54) compared with the lowest fifth. A meta-analysis pooling prospective cohorts found about 12% higher risk for every 10% increase in the share of the diet that is ultra-processed.^[2] Those are associations in people who reported what they ate. They don’t prove cause.

The new study adds a possible mechanism: a repeated, larger insulin response to ultra-processed meals. It does not show that this response causes insulin resistance or diabetes. It tested one meal in young, healthy people, and the insulin difference faded within three hours.

What this study can’t tell you

• It was one 300-calorie meal. The authors note that larger meals may behave differently.^[1]
• The meals weren’t perfectly parallel. Protein was matched in total, but the protein sources differed, which could affect insulin. The ultra-processed meal also had more additives, and the study didn’t isolate which feature drives the effect.^[1]
• The group was young and lean. We don’t know if the gap is bigger, smaller or the same for adults over 40 with higher body fat or existing insulin resistance.
• Not everyone finished. 25 of the 57 participants did not complete both metabolic sessions, and the ultra-processed meal was eaten about 1.5 minutes more slowly on average.^[1]
• No one was followed for years. The study measured hours, not disease.

What to do with it

The evidence supports a modest, practical move rather than a sweeping diet overhaul.

• Pick one meal a day to build from minimally processed foods. Think eggs, plain yogurt, cheese, fruit, nuts, beans, a baked potato, or leftover cooked meat. Breakfast and lunch are usually the easiest to change.
• Read the ingredient list, not just the nutrition label. Matched macros hid a real difference in this study. If the label lists ingredients you wouldn’t keep in your own kitchen, treat it as ultra-processed.
• Don’t rely on a glucose sensor alone. If you wear one, it doesn’t show insulin. Ask your clinician whether a fasting insulin level, HOMA-IR or HbA1c makes sense for you, especially if diabetes runs in your family.
• Keep your own medication plan. If you take medication for blood sugar, talk with your clinician before changing your diet substantially, and don’t start, stop or change a medication on your own.

This study is one piece of the picture. The cohort data point the same direction, but they show association, not proof. It gives you a reason to look past the glucose number.

References

[1] Hutelin Z, Ahrens M, Baugh ME, Nartey E, Herald DL, Hanlon AL, DiFeliceantonio AG. Metabolic and neural responses to ultraprocessed foods: a randomized, controlled, crossover study. Nat Metab, 2026. Population: 57 healthy-weight adults (mean age 26.2, mean BMI 22.75); 32 completed both whole-room calorimetry sessions. DOI: https://doi.org/10.1038/s42255-026-01619-4. Finding as used: nutritionally matched ~300 kcal ultra-processed and non-ultra-processed meals produced similar glucose area under the curve (P = 0.92) but greater insulin area under the curve after the ultra-processed meal (P < 0.001), with insulin higher at minutes 40, 60, 90 and 120 and near baseline by 180 minutes; metabolic rate area under the curve was greater and carbohydrate oxidation attenuated after the ultra-processed meal; limitations include differing protein sources and a single small meal. ↑︎

[2] Chen Z, Khandpur N, Desjardins C, et al. Ultra-Processed Food Consumption and Risk of Type 2 Diabetes: Three Large Prospective U.S. Cohort Studies. Diabetes Care, 2023;46(7):1335-1344. Population: 71,871 women (Nurses’ Health Study), 87,918 women (Nurses’ Health Study II) and 38,847 men (Health Professionals Follow-Up Study); 19,503 type 2 diabetes cases; meta-analysis of 415,554 participants. DOI: https://doi.org/10.2337/dc22-1993. Finding as used: hazard ratio for type 2 diabetes of 1.46 (95% CI 1.39-1.54) comparing extreme quintiles of ultra-processed food intake; in the meta-analysis, each 10% increment in ultra-processed food was associated with 12% (95% CI 10%-13%) higher risk. Observational data. ↑︎

Kurt Greiner

Kurt is a digital strategist and IT professional blending emerging technology with practical application to help businesses and individuals streamline their digital presence. His current work focuses on the intersection of intentional living and technological resilience, exploring how individuals can leverage modern tools to navigate the second half of life with purpose.