Eating something and having it absorbed in your intestines are two different things. As anyone who’s ever looked into supplements knows, the bioavailability—the amount that actually gets into your bloodstream and put to use—of most supplements is very low, even as low as [4% for magnesium oxide](https://pubmed.ncbi.nlm.nih.gov/11794633).
I’m wondering what is the bioavailability of starch in foods like potatoes, oatmeal, rice, lentils, etc. How much do your intestines absorb and how much passes through? What factors affect the bioavailability of starch? I haven’t had much luck googling.
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I’m asking because I’ve been starving on a WFPB diet for the past month or so despite eating an average of 2,668 calories a day (though varying a lot from day to day). That number agrees with my calculated total daily energy expenditure, so it appears that I’m not running a calorie deficit. (I’m 56, male, 6’1″, 177 lbs., moderately active.) The hunger is worst on days when I eat a huge amount of starch, though; the hunger is somewhat reduced on days when I eat a huge amount of fat. I get extremely *full,* to the point where I can’t eat any more, but the fuller I get with starchy foods, the hungrier I feel.
If you know something relevant to my situation, that would be great, but I’d just like to know what the research has established about bioavailability of the energy content of starchy foods.
Dining and Cooking