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December 4, 2025<\/p>\n
Add Us On Google<\/span>Add SciAm<\/span><\/span><\/p>\n Why Leftover Pizza Might Actually Be Healthier<\/p>\n Researchers have discovered that cooling starchy foods\u2014from pizza to rice\u2014creates \u201cresistant starch,\u201d a carb that behaves like fiber and alters your blood sugar response<\/p>\n By Tom Lum edited by Kelso Harper<\/span><\/p>\n This video is part of \u201cInnovations In: Type 1 Diabetes,\u201d an editorially independent special report that was produced with financial support from Vertex.<\/p>\n Tom Lum: On the surface, this may look like your garden-variety Internet fun fact, the kind that you half remember and try to retell at a party, like …<\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n [Lum pretends to be a guest at a party. He is holding a slice of pizza and talking over music.]<\/p>\n Lum: Did you know I read somewhere that leftover pizza is actually better for\u2014uh\u2014so how do you know Lauren?<\/p>\n But the secret is that this is just the surface of the fact, and the deeper we go, the more fun and weirder the science gets.<\/p>\n Because your first thought on hearing this is probably \u201cWhy?\u201d Why is leftover pizza healthier for me? And the answer has to do with what happens when you cool the delicious crust. When you cool a pizza to below 40 degrees Fahrenheit, some of the starches in the dough will start to mingle together to form these long chains called resistant starches.<\/p>\n They resist digestion, and another word for a carbohydrate that resists digestion is fiber! And even if you reheat the pizza, the chains stay intact, so your body doesn\u2019t break them down to sugar. They mostly pass through.<\/p>\n This could help reduce blood sugar spikes for people with diabetes or people who just need more fiber for a healthier gut. And this seems to work for a lot of starches, like rice, pasta, potatoes\u2014even beans and lentils. Heating then cooling the starch changes its properties. It\u2019s like tempering chocolate or forging a stronger steel.<\/p>\n But we can go even deeper into this fun fact because another question you might have is \u201cHow?\u201d How did scientists study, analyze, and figure this out? And for that, we need to go to the actual papers.<\/p>\n And this is where you\u2019ll find electron microscope photographs of old rice, showing these long starchy fibers forming and then sticking around through \u201csimulated digestion.\u201d And you\u2019ll also find studies on humans to try to measure these health changes, like this one where brave participants had to be at the lab at 6 A.M. to eat old rice for science, which they had to do so that nothing else they ate that day interfered with their measurements.<\/p>\n This study also measured how long participants were chewing the rice, which may seem like overkill until they point out digestion starts in the mouth. And it\u2019s this clever attention to detail that is the most important part because that\u2019s how you get the fun fact.<\/p>\n Like, humans have been eating food the entire time humans have existed, but the way it interacts with our body is so complex that we\u2019ve only just learned that apparently our fridge is a forge for fiber. And I think that and the details of the study are so much more interesting than the fun fact. It just might not be the best at parties.<\/p>\n [Lum pretends to be a guest at a party again.]<\/p>\n Lum: Hi, it\u2019s Tom. Did you know digestion starts at the mouth?<\/p>\n If you enjoyed this article, I\u2019d like to ask for your support. Scientific American<\/span> has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.<\/p>\n I\u2019ve been a Scientific American<\/span> subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm <\/span>always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.<\/p>\n If you subscribe to Scientific American<\/span>, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.<\/p>\n In return, you get essential news, captivating podcasts, brilliant infographics, can’t-miss newsletters, must-watch videos, challenging games, and the science world’s best writing and reporting. You can even gift someone a subscription.<\/p>\n There has never been a more important time for us to stand up and show why science matters. I hope you\u2019ll support us in that mission.<\/p>\n","protected":false},"excerpt":{"rendered":" December 4, 2025 Add Us On GoogleAdd SciAm Why Leftover Pizza Might Actually Be Healthier Researchers have discovered that cooling starchy foods\u2014from pizza to rice\u2014creates \u201cresistant starch,\u201d a carb that behaves like fiber and alters your blood sugar response By Tom Lum edited by Kelso Harper This video is part of \u201cInnovations In: Type 1<\/p>\n","protected":false},"author":1,"featured_media":36095,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[58],"tags":[2256,9465,20218,18082,17584,516,20219],"class_list":{"0":"post-36094","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-explained","9":"tag-healthier","10":"tag-leftover","11":"tag-pizza","12":"tag-resistant","13":"tag-science","14":"tag-starch"},"_links":{"self":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/36094","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=36094"}],"version-history":[{"count":0,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/36094\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/media\/36095"}],"wp:attachment":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=36094"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=36094"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=36094"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}On supporting science journalism<\/h2>\n
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