What the research found

Researchers created two matched meals with identical macronutrient profiles, fiber content, sodium, and glycemic index—one made from ultra-processed ingredients and one from minimally processed whole foods. Despite producing similar blood glucose responses, the ultra-processed version triggered a notably higher insulin response. Additionally, the body showed slower oxidation of the carbohydrates consumed after the processed meal, suggesting impaired metabolic flexibility (the ability to efficiently switch between fuel sources).

Brain imaging during the study revealed that the reward-processing regions responded differently to the two meals, even though nutritional breakdowns were equivalent. This points to mechanisms beyond simple macronutrient composition that differentiate food processing levels and their physiological effects.

Why it matters for you

If you're relying on a continuous glucose monitor (CGM) as your primary feedback tool, this research suggests you're only seeing half the picture. Two meals could show nearly identical glucose curves on your device yet produce very different insulin demands on your body. Since elevated fasting insulin and poor insulin sensitivity are red flags many MyKine users track, this means processed foods might be silently worsening your metabolic state even when CGM data looks reassuring.

The finding also speaks to metabolic flexibility—your ability to burn carbs efficiently when they're available and switch to fat metabolism during fasting or low-carb periods. If ultra-processed foods impair this switching ability, they may be undermining performance during training, recovery quality, and fat-loss protocols. This could explain why some people plateau despite "clean" macros.

The practical takeaway: inspect ingredient lists as a first filter before considering a food's fit into your protocol. Highly processed foods may impose hidden metabolic costs that standard nutrition labels—and even CGM readings—won't capture.

Caveats

• Study details not provided: effect size, sample size, and whether findings were acute or sustained over time are unclear from this summary
• Brain imaging correlation: while interesting, differences in reward-region activation don't directly prove metabolic harm or explain mechanism
• Real-world applicability: a controlled lab meal may not translate to how your body handles processed foods in mixed meals or over days
• Individual variation: insulin response to processing level likely varies by baseline insulin sensitivity, gut microbiome, and training status