# How resistant is Resistant Starch? **URL:** \ **Category:** Factual Questions\ **Created:** [September 8, 2023, 4:20pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791 "2023-09-08T16:20:14Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 8, 2023, 4:20pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/1 "2023-09-08T16:20:14Z")
Other than this [thread](https://boards.straightdope.com/t/isnt-resistant-starch-just-fiber/569295) from 2011, I haven’t been able to find more recent info here on resistant starch. I ask because I still find controversy about whether it even exists. I think it’s safe to say Resistant Starch exists, at least for foods like potatoes, oats, and green bananas, but do we know how much of their starch becomes resistant by cooking and putting it in the fridge overnight before eating? I’ve seen anywhere from 2-3% up to 30% in some articles (no cites). Is there a factual answer as to how much starch actually becomes resistant when it is chilled? ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 9, 2023, 3:32am UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/2 "2023-09-09T03:32:27Z")
For [potatoes](https://pdf.sciencedirectassets.com/271163/1-s2.0-S0308814616X00106/1-s2.0-S0308814616305052/am.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjENv%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaCXVzLWVhc3QtMSJHMEUCIQDObXtNNWeEogrhU73DvXYQVuf7f7VklcuRMe%2Bz9hClEQIgWcSQDess40JJCxPl2HRe14EIZElBuk%2FRkZayobED%2F%2FgqvAUItP%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARAFGgwwNTkwMDM1NDY4NjUiDGYdYTrafQYNRABseiqQBUtTjq09MemccGgCBW7Da5%2FnLDugsbSYeHNyP7bwZVM2DljPfVgq1DKDP1lQpderWo7wEXc2z7UPX2gu60flVuhcBr%2FxwMFjIxtZvvDKQYWvx7G31tu2bE7M9%2BFEAIn2n0fid3W3Hk8z1YlHSxFWH7PZNT5kKEmSQRlksQ5eWmFvulMNTChLFnSOLek9P3VLlVosxKsT1FsvNbdHm19ir%2F8McG%2B6El%2BA%2BYpQ6hkLJTBdI2ilbo7T6GH1zXvWf%2FrsD6DU7EJ8mpnHPFOEO4hS2AnmWE7EaeqLzaPaz0yaE79aV9NaYEhfAclPG31XJLaMw3BNTdaOVMSDjTvQbbm3wZj480v%2BMtmvroK8gc2uwVJdZm4Bsgq1oVLys%2F8bvPUeU9hlUq4wVnbauOjz%2B6SOHIkxD6TmKWXAp3bhetvmtYJk0uv2vn22426wT2NNz3kWVrRMg97%2F3q%2BG1nsGtIAItW1rnWXY1hqsb8ipkBXe2onDUS3fTdqa%2BFqchp0atkttvdBz0F0I0i%2Fj%2FL%2Fs5JeoaVAwTRV5JEPCPHtMlnFaqbvXlgu7lQKjMW8uTKoZkhAp8oQ3Bc02mwDebaQPFN0BGnFp3WRxU0oV1baos0Hv119zq882plbfFaHYLeDzcZ8icK8OwTKxqW7T43KzxnzNS29bXjsja37VHirtNh4CRUc%2BEB6qtJ%2F1Wew4rJzxNMEi%2Fscrq8feRT5U4cHZCgoI2DXE2Hnpdn8%2BQd9F7qgKwJ%2FOFv00qbgJiDo%2B0r6qaldeXAkXZewHOr55xxDrgEVKWowoP8toPcpglAO5jlNY1sYAORnyM4CJ3h0TSQcSCbuviVsmUuDVVfH4Y%2FIS9GVVO%2F2F28OJ94j%2B08XszQn%2BEV7GMK2y76cGOrEBP2Cr2YKNNdrCveV8pjA5qQ%2Fjbreor3jpsWYXc9vVTbSwoV1YlbAfwSU92RYxEDOW6gNYKWfmxhrcEBoyoY7r5W%2B%2BqocB453vCL4yhvynPOHlh%2FpgTQJyBD6HX%2BkzuLcyt6XScpDOmdykdmHzipZj8yr8h5Iz2PdJWiHU4h4%2FNEggbqnxm583N%2BfoupazHUq1TKlf1RpveZyxq2mKUSBr90dQXnGp3d3THIVJsXn5S%2FXx&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20230909T031731Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTY4W2LCRGA%2F20230909%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=0cc2a328f5ec0b5633611e4543e3fb36fcf01cb9ba97ff946aa25bedd5072530&hash=bd1462b818a12f13f0cf6c6e59725d0f98fb11c73ec473da183ed1c83f82d48c&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S0308814616305052&tid=pdf-837a72af-6d01-4273-881e-a1ed370a7ed0&sid=8f72a18337d66347b03ba073d412b231ae9agxrqa&type=client): Table 1 near end of article. On average 43% increase chilled over hot. Decent range though. Baked significantly more than boiled. And I found this claiming a huge increase, like ten-fold, in rice prepared a specific way and chilled. [https://time.com/collection/guide-to-weight-loss/3754097/rice-calories-resistant-starch/#](https://time.com/collection/guide-to-weight-loss/3754097/rice-calories-resistant-starch/#) ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 9, 2023, 3:43am UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/3 "2023-09-09T03:43:07Z")
Thanks. That’s just what I was looking for. ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 9, 2023, 4:14pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/4 "2023-09-09T16:14:58Z")
Since I’m wearing my CGM I added an experiment to see if I notice a drop in my BGL when I turn steel cut oatmeal into (partially) resistant oatmeal as part of my standard breakfast. I’ll let you know if it’s noticeable or not. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 9, 2023, 5:02pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/5 "2023-09-09T17:02:48Z")
For your intellectual pleasure: all about oats and resistant starch (RS)! > **[Oat-Based Foods: Chemical Constituents, Glycemic Index, and the Effect of...](https://www.mdpi.com/2304-8158/10/6/1304)** > > The desire for foods with lower glycemic indices has led to the exploration of functional ingredients and novel food processing techniques. The glycemic index (GI) is a well-recognized tool to assess the capacity of foods to raise blood glucose... Highlights (to my read): > [@](#): > > RS accounts for 29.31% of the starch content in raw granular form of oat starch [[25](https://www.mdpi.com/2304-8158/10/6/1304#B25-foods-10-01304)]. The RS in raw oat starch is named RS2 starch, where its slow digestion is mainly due to the compact nature of the starch granules making the starch less accessible to enzymes. Since the amylose–lipid complex is resistant to enzymatic breakdown, the high lipid content in oats (3–7%) may be another reason why oat has a relatively high level of RS starch. This type of RS is called RS5 [[26](https://www.mdpi.com/2304-8158/10/6/1304#B26-foods-10-01304)]. In addition to being less susceptible to enzymatic breakdown in the upper gastrointestinal tract, the effect of RS on GI is also subject to modulation by gut microbiota, as described in several publications [[27](https://www.mdpi.com/2304-8158/10/6/1304#B27-foods-10-01304),[28](https://www.mdpi.com/2304-8158/10/6/1304#B28-foods-10-01304),[29](https://www.mdpi.com/2304-8158/10/6/1304#B29-foods-10-01304)]. Although RS2 occurs naturally, most of the starch needs to be cooked for consumption. In this case, RS3 that is formed due to the recrystallization of gelatinized starch is more commonly consumed by processing via gelatinization and retrogradation, which will be discussed in the following sections. … > > … the degree of oat starch retrogradation is limited compared to that of other cereal grains, because the presence of lipid interferes with the process to a certain extent [[76](https://www.mdpi.com/2304-8158/10/6/1304#B76-foods-10-01304)]. The degree of retrogradation in oat starch was substantially lower than that in wheat starch (42.04%) when stored at 4 °C [[77](https://www.mdpi.com/2304-8158/10/6/1304#B77-foods-10-01304)]. The retrogradation of amylose can generate type 3 resistant starch (RS3). It was reported that RS3 showed the therapeutic effect on Type 2 diabetes through improving dyslipidemia, reducing insulin resistance, and increasing insulin sensitivity [[78](https://www.mdpi.com/2304-8158/10/6/1304#B78-foods-10-01304)]. Compared with other plants, especially legumes, the RS3 content formed in oats is relatively low [[79](https://www.mdpi.com/2304-8158/10/6/1304#B79-foods-10-01304)]. … > > … oat bran supplementation in foods is an effective strategy for increasing oat β-glucan content. As with β-glucans in general, the quality and quantity of oat β-glucans in oat bran determines how glycemic behavior is affected. Therefore, processes such as extrusion may affect the molecular weight of the β-glucans and thus change the GI of oat bran [[74](https://www.mdpi.com/2304-8158/10/6/1304#B74-foods-10-01304)]. In addition, the bran layer is also a primary source of oat phenolics, and these compounds may reduce the GI by their inhibitory activity against α-amylase and α-glucosidase [[104](https://www.mdpi.com/2304-8158/10/6/1304#B104-foods-10-01304)]. … > > … Minimum mechanical processing (grain) maintains the intact cell wall and larger particle size that reduce the accessibility to enzymes and thereby tend to enable lower GI values. In contrast, ultra-processing makes the starch more easily hydrated and increases the surface area available to enzymes. Another typical product, oat bran, affects GI behavior through the enrichment of dietary fibers. The systematic summary of GI of oat products with different physical formats presented in this review helps to synthesize knowledge of the field and provides practical guidance useful for management of diabetes with diet. … Short version? Whole grain oats are great, oat bran maybe even a bit better. Cooling though does not increase RS levels as much as cooling does for many other cereal grains. But let’s see what your personal experience shows! ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 9, 2023, 8:24pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/6 "2023-09-09T20:24:00Z")
> [@DSeid](#): > > But let’s see what your personal experience shows! I finished my experiment, and the results seems to back the claims made about resistant starch being indigestible in the small intestine and therefore not contributing to my glucose spike. I ate two identical breakfasts, the only difference was that for Day 1 I had cooked the 1/2 cup of dry rolled oats (not instant) the day before and let it sit in the fridge overnight. For Day 2, I cooked the same amount of oatmeal and ate it without letting it cool. According to my CGM data there was a 7% reduction in my breakfast glucose spike when I cooked and cooled the oatmeal before eating it. I wouldn’t call that a significant reduction, but it at least proves to me that resistant starch and retrogradation is a real thing and can be used to flatten a glucose spike, even if only by 7%. I plan to also test this for rice and potato if I get a chance before my CGM expires. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 9, 2023, 8:52pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/7 "2023-09-09T20:52:24Z")
Follow the directions on the rice cooking! Their trick includes adding the oil during the cooking. (1 tsp to half a cup of rice.) They specifically used coconut oil but I’ve read [another study](https://pubmed.ncbi.nlm.nih.gov/32771516/) that claims rice bran oil does even better (more long chain unsaturated fatty acids apparently). I’d also be curious to see your real world result comparing white to red rice (the study found red rice had the least glycemic response). ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 9, 2023, 9:20pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/8 "2023-09-09T21:20:54Z")
I’ve don’t see red rice in the store. I’ve already switched over to brown rice since it’s less processed than Basmati rice AFAIK. I want to compare white rice to brown rice to see what the spike difference is, if any, and then prepare and eat them both after retrogradation. I plan to try the coconut oil method too to see if it makes as big a difference as it’s suppose to. I’m a big fan of rice and would like to bring it back into my diet if I can get away with it. Stay tuned. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [September 9, 2023, 10:27pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/9 "2023-09-09T22:27:49Z")
> [@dolphinboy](#): > > I’ve already switched over to brown rice since it’s less processed than Basmati rice AFAIK. Note that brown Basmati rice is available. ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 9, 2023, 10:45pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/10 "2023-09-09T22:45:46Z")
Thanks. I thought all Basmati rice was white since that’s all we used to buy. Live and learn. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 12, 2023, 5:37pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/11 "2023-09-12T17:37:12Z")
> [@dolphinboy](#): > > I plan to also test this for rice and potato if I get a chance before my CGM expires. And? Curious minds …. ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 12, 2023, 6:01pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/12 "2023-09-12T18:01:37Z")
I was able to confirm from my testing that Basmati white rice, russet potato, and old fashion oatmeal all exhibit resistant starch when cooled overnight in the fridge. In general my BGL was lowered 7-10% compared to not cooling them. Since I didn’t just eat these starches alone it’s hard to say with absolute certainty that the differences I saw were due entirely to the resistant starch, but that certainly seems to be the case. I haven’t tried the special rice cooking with oil yet or sweet potatoes and hope to get to them later this week, but time is running out. From my prospective, resistant starch isn’t bunk, however people may be disappointed in the amount of difference it seems to make. Clearly scholarly studies need to be done to quantify the impact resistant starch has on blood sugar levels for the general population. For me, even a small reduction in my blood glucose spike is worth doing when I am eating at home. YMMV. I will be winding up the 28 days of testing on Saturday and will look through my data and report back my conclusions from the testing. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 12, 2023, 6:12pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/13 "2023-09-12T18:12:58Z")
Thanks. To be noted - The putative advantages of RS are more than altering the immediate glucose curve. And a BG peak 7% less seems big to me btw After they apparently get to the gut microbiota they get fermented into short chain fatty acids which then do all sorts of positive signaling on inflammation and appetite. One claim made in the popular press article about it was that it makes the food significantly less caloric. That I do not buy. The short chain fatty acids then provide energy too … Maybe a bit less caloric? ---
**Author:** ![CairoCarol](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cairocarol/32/3825_2.png) [@CairoCarol](https://boards.straightdope.com/u/CairoCarol)\ **Post date:** [September 12, 2023, 6:18pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/14 "2023-09-12T18:18:25Z")
> [@dolphinboy](#): > > I’ve don’t see red rice in the store. I buy [this red rice](https://www.amazon.com/Dragonfly-DFTRR01-Red-Rice-5-Pound/dp/B005S9TJ5U/ref=sr_1_6?crid=1WH4J70TWFKHR&keywords=red+rice&qid=1694542534&sprefix=red+rice%2Caps%2C583&sr=8-6) on line and love it. Red rice is more common in Asia and I find it (as well as black rice) to be far more delicious than brown rice. Anytime I cook something that calls for brown rice, I use red rice instead. Far better. You can also mix a little bit (maybe up to 1/3 of the total) of red rice to white rice that you cook in the rice cooker. It results in a tastier, more colorful, and more nutritious rice dish. ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 12, 2023, 8:11pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/15 "2023-09-12T20:11:05Z")
Good idea. I’ll that. ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 12, 2023, 9:51pm UTC](https://boards.straightdope.com/t/how-resistant-is-resistant-starch/989791/16 "2023-09-12T21:51:54Z")
I meant to say I’ll try that!