[Kirby64]

Thermic effects of food are very marginal. Especially if you’re comparing something like oats and finely ground oatmeal instead of two wildly different foods like oats vs meat. I’d suspect the difference is at most 5%, likely much lower, which is within the margin of error for caloric reporting of labels. Humans are very efficient at extracting nutrition from food.

[orwin]

No. Diet Induced Thermogenesis (DIT) can vary from 0-3% (for fat) to 20-30% (for proteins). Carbs usually vary between 5 and 30%, depending on the amount of fiber. A fiber-rich oat would likely be around 30%,and a fiberless oatmeal 10-20%.

[Kirby64]

Please read the context again. If the only difference is oats vs finer ground oats, fiber would not be removed and nutrition content would be the same. Simply grinding up something doesn’t destroy its fiber content. If there’s additional processing to remove something such as fiber content then that would have an effect, but now we’re not just making particles smaller.