Emerging studies suggest that heavily processed foods trigger elevated insulin responses even without significant blood sugar increases, raising concerns over their role in insulin resistance and diabetes risk.
Ultra-processed foods may do more than simply add calories to the diet: new research suggests they can keep insulin elevated even when blood sugar does not rise dramatically. Scientists at the University of Colorado examined how the body responded to meals and found that the more heavily processed options triggered a stronger insulin response, an effect that could matter over time because persistently high insulin levels are linked to insulin resistance and, eventually, type 2 diabetes.
The lead researcher, Alexandra DiFeliceantonio, said she was initially surprised that the foods did not produce a marked jump in blood glucose. Speaking about the findings, she said she even called the laboratory to check whether there had been a mistake in the data. The samples, however, had been analysed without the lab team knowing which meal they came from, making the result harder to dismiss. Her explanation is that ultra-processed foods may behave almost like “predigested” products, because high heat, industrial refinement and enzymatic breakdown can make nutrients easier for the body to absorb.
Sandra Zhang, a registered dietitian-nutritionist at Tufts Medical Center in Boston, said that faster digestion is a plausible reason for the insulin effect. In her view, ultra-processed foods can release nutrients more quickly, which may drive a quicker hormonal response even when the sugar reading itself does not surge immediately. Zhang also noted that in everyday life people often eat larger amounts of these foods, meaning the real-world impact may be greater than in a tightly controlled feeding study.
That concern fits with a broader scientific picture. A systematic review and meta-analysis published in the International Journal of Epidemiology found that both moderate and high intake of ultra-processed foods was associated with a higher risk of developing type 2 diabetes, with risk rising alongside consumption. Separately, a Diabetes Care study drawing on three large United States cohorts found that greater intake of ultra-processed foods was linked to a higher likelihood of diabetes, with sugar-sweetened drinks and ultra-processed meats standing out as especially concerning. A 2024 University of Texas at Austin analysis also reported that heavier consumption of ultra-processed foods, including diet versions, was associated with higher blood sugar levels in people with type 2 diabetes, suggesting that additives and processing itself may matter beyond sugar and salt alone.
Experts caution, however, that the new findings have limits. The study was relatively small, the test meals differed in protein sources and the ultra-processed meal contained more additives, any of which could have influenced the response. Even so, the broader message is consistent: food processing may change the way the body handles what it eats, not just how many calories are present. DiFeliceantonio argues that the emphasis should not be on repeating that ultra-processed foods are unhealthy, but on asking why the modern food environment makes them so hard to avoid. Zhang’s advice is more straightforward: choose minimally processed foods most of the time and treat ultra-processed products as occasional items rather than staples.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
