The Short Version
The claim is directionally accurate but overstated. Multiple peer-reviewed studies, mechanistic reviews, and clinical guidance consistently link ultra-processed food consumption to insulin resistance markers. However, most evidence uses associative language ("linked to," "associated with"), not definitive causal proof. Key confounders — obesity, sedentary lifestyle, and overall diet quality — remain inadequately separated from the independent effect of processing. The claim also says "processed food" broadly, while the evidence specifically addresses "ultra-processed foods," a narrower category. The relationship is strong and biologically plausible, but the word "causes" goes beyond what current science has firmly established.