A few years back, I briefly covered an article about how “carbs will make you lose weight” because so many readers had emailed about it. It turned out that the “carbs” in the article were resistant starch, a type of carbohydrate that our digestive enzymes cannot break down. I’ll admit now, with regret, that I didn’t look as deeply into the matter as I might have. I didn’t dismiss resistant starch, but I did downplay its importance, characterizing it as “just another type of prebiotic” – important but not necessary so long as you were eating other fermentable fibers. While technically true, we’re fast learning that resistant starch may be a special type of prebiotic with a special place in the human diet. Before I go any further, though, a series of hat tips to Richard Nikoley, Tatertot Tim, and Dr. BG, whose early and ongoing research into the benefits, real-world implications, and clinical applications of resistant starch have proved to be a real asset for the ancestral health community. Oh, and I even hear tell that they’re writing a book on the subject. Interesting… In subsequent Dear Mark articles, I’ve since given resistant starch a closer, more substantial look, and today I’m going to give it the definitive guide treatment. Instantly download your free Guide to Gut Health What Is Resistant Starch? When you think about “starch,” what comes to mind? Glucose. Carbs. Elevated blood sugar. Insulin spikes. Glycogen repletion. Basically, we think about starch that we (meaning our host cells) can digest, absorb, and metabolize as glucose (for better or worse). Officially, resistant starch is “the sum of starch and products of starch degradation not absorbed in the small intestine of healthy individuals.” Instead of being cleaved in twain by our enzymes and absorbed as glucose, resistant starch (RS) travels unscathed through the small intestine into the colon, where colonic gut flora metabolize it into short chain fatty acids. Thus, it’s resistant to digestion by the host. There are four types of resistant starch: RS Type 1 – Starch bound by indigestible plant cell walls; found in beans, grains, and seeds. RS Type 2 – Starch that is intrinsically indigestible in the raw state due to its high amylose content; found in potatoes, bananas, plantains, type 2 RS becomes accessible upon heating. RS Type 3 – Retrograded starch; when some starches have been cooked, cooling them (fridge or freezer) changes the structure and makes it more resistant to digestion; found in cooked and cooled potatoes, grains, and beans. RS Type 4 – Industrial resistant starch; type 4 RS doesn’t occur naturally and has been chemically modified; commonly found in “hi-maize resistant starch.” It’s almost certain that different RS types have somewhat different effects on our gut flora, but the specifics have yet to be fully elucidated. In general, RS (of any type) acts fairly similarly across the various types. Where Do We Get It? We can get RS from food. The richest food sources are raw potatoes, green bananas, plantains, cooked-and-cooled potatoes, … Continue reading The Definitive Guide to Resistant Starch