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Hey everyone, it's Mikki here. You're listening to Mini Mikkipedia on a Monday. And today I wanna chat about glycemic index, glycemic load, and importantly, glycemic response. What the differences are between these three things and what you actually should focus on. So the reality is, is that not all carbs hit the blood sugar the same. And not all carbs hit blood sugar the same for different people or the same person

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in different scenarios. So today we're to talk about how useful a concept glycemic index is compared to your actual glycemic response, because that's actually the most important piece of the glycemic puzzle. So first and foremost, what even is glycemic index? So in plain English, and you will see this a lot marketed on different products, carbohydrate products, it's a marker of carbohydrate.

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Glycemic Index ranks carb containing foods by their two hour blood glucose rise versus pure glucose. And it uses a standardized lab protocol. So it's a property of food in a lab essentially, not you on a Tuesday. Now I've got a funny story about Glycemic Index and I have shared this before. So feel free to skip the next 30 seconds if you've heard it. But when I was in doing my master's degree,

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down in Otago, we were one of two labs in the southern hemisphere that were looking at glycemic index of food. And this was, I think, 2000, 99, 99 or 2000. And so as postgraduate students, we would get maybe 50 bucks if we rocked on up to a lab at like 6 a.m. or 7 a.m. in the morning. And we essentially got a load of food that equated to 50 grams of glucose.

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we had to stay in the lab and get our blood sugar response measured over the course of a two hour period. And I think blood sugar might've been measured at 15 minutes, 30 minutes, 60 minutes, 90 in two hours or something like that. Anyway, so we were all just poor master's students. And it was a couple of sort of insights to that process is of course we had to do everything standardized and the researchers at the time, Tim, can't remember Tim's last name, great guy. He was like, okay.

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So you guys have to do everything by the letter. And of course you're like, yeah, of course, this is really important. But none of us did. Like a couple of us went for a run before we turned up at the lab. Like we just sort of played around in the lab. And it just really highlighted to me that, you know, here we are contributing to nutrition research, being in the field and not really taking seriously what the researcher was telling us to do. So that was sort of makes me laugh thinking about it now, because, oh my gosh, it just tells you what the human, what humans are actually like, right?

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Another thing that was super fun as part of that lab. So we did this several times with different foods like white bread, multigrain bread. think juice was one, maybe a cereal was another, and we were going to be doing carrots, but literally we would have had to have eaten like maybe two kilos of carrots to get 50 grams of available glucose. So we didn't do carrots anyway. know, it pretty much nutrition science is pretty much an imperfect science, but I do feel like, wow, how

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incredible actually that we were part of this sort of foundational research looking at glycemic index, which has obviously been popularized by Jenny Brand Miller's lab over in Sydney. But all of the values that are given for foods are based on lab values, pretty much set up the way that I talked about in a standardized lab protocol. There are cutoffs for glycemic index as well, low being under 55. So this therefore means that a

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50 grams of available carbohydrate in that food is going to predictably have a low glycemic index value. Medium is 56 to 69, high is over 70. And it's on a scale up to 100. Importantly, is glycemic index tables are huge, right? There are over 4,000 items. There's been an update in 2021. However, method, variety, ripeness, and cooking

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all shifts the glycemic index value. So you sort of, want to treat glycemic index like a map, if you like, but not as this specific GPS point, because it might give you a trend or a direction of how a food might go and how you might respond from a glycemic perspective, but it could be well off. And a really interesting update on the glycemic index values, which people don't often think about, is of course potato versus kumbira. And

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Back in the day when we were doing these tests, kumara initially was considered a low GI food, whereas potato was high. And this is part of the reason why potatoes were so villainized compared to kumara or sweet potato. And subsequent glycemic index testing of kumara or sweet potato found in fact it was as high, if not higher, than potatoes. So that's not.

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knowledge that people know that much about and also it's probably even not that meaningful. And the reason I say that is because, you know, glycemic load might even be more important. So I just said that glycemic index refers to 50 grams of available glucose in a food and glucose is of course that breakdown product of carbohydrate in a particular food of which all carbohydrates have. So 50 grams of available glucose is very variable. Like if you've got white bread, it might be three slices of white bread.

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If you've got apples, it might be three large apples. So your ability to consume 50 grams in one hit is obviously going to influence how your blood sugar responds because if 50 grams of glucose might be in eight servings of something, you're very unlikely to hit that threshold for it to be a meaningful number for you to focus on in terms of glycemic index. So glycemic load is possibly more important. Glycemic load is the glycemic index of a food

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times the grams of available carbohydrate in your portion divided by 100. And the glycemic load, there are different cutoffs with low being less than 10, medium being 11 to 19, and high being over 20. And this matters because the glycemic load brings the portion size into it, which is super important, obviously. So it brings it into the real world. For example, watermelon is often thrown under the bus as being a high GI food, but it's

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typically has very few servings of carbohydrate because it's so water rich. And in fact, it has a low glycemic load. So you can eat a lot of watermelon before you hit that 50 grams sort of glycemic index threshold, if you like. So context of how you eat it really does change that sort of glycemic index curve. So there are food factors which change the glycemic index. You've got the rightness of things like bananas.

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particle size, so steel cut oats versus instant oats. The cooking and cooling of food, again, like rice and potatoes come into this. So when you cook a potato and you cool it down, part of the starch in that potato gelatinizes and it then resists digestion. So in fact, you reduce the available carbohydrate in that food. So if you're eating potato and you've got blood sugar management issues, you're better off cooking that potato, cooling it down,

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and then bringing it out of the fridge the next day, because it needs to be completely cold. And even if you reheat it, some of that resistance starts to remain. So that's a way better way for you to eat the potato than to have it fresh out of the oven. Of course, if you don't have blood sugar issues or you're having your potato with other foods, probably isn't as important. Which brings me to my next point is that glycemic index measures just the food in isolation, whereas we don't eat food in isolation. We pretty much pair

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all of our food is part of meals. So we eat in these mixed meal situations. Protein, fat, fiber, acids like vinegar, these all affect how your body responds to the carbohydrate in the food, which to me tells me that glycemic index as a measure is pretty useless actually because it has no context. And we're very reductionist in nutrition. When we think about nutrients, we think about different foods, we think about glycemic index, it's a very reductionist approach. Instead,

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We need to think much more broadly and much more about how we eat and in what context we eat, because that is all going to change how people respond. In addition to that, our baseline insulin sensitivity, the amount of sleep we've had, the time of day, the amount of stress we're under, if we've done any recent exercise, i.e. like gone for a run and then tested the glycemic index of a particular food, and our gut microbiome can all play a role in how our body responds to the carbohydrate, which

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really is that glycemic response and which is why it's so important. And there have been big data sets such as the PREDICT data set, which shows that there's large between-person variability to the same standardized meal. While within-person repeatability is better, it can still change on that day to day. So how a food affects me is likely quite different to how it's going to affect you, even if we are of a similar height and weight and exercise level. So

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The glycemic index is really about what happens to that food in a laboratory setting. Glycemic response is much more about you and how you respond. And glycemic load is also an important piece of that. So is it still even useful? Which I think is a really good question to ask. So where it can help is a tiebreaker within a category for some people. So rice varieties, pasta, bread type.

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and it can help as an education tool about processing and cooking effects. And I really like that idea actually. Where it does fall short, as I mentioned, is when you're eating whole mixed meals, which is pretty much what we do in everyday life. When we're comparing foods with very different carb loads, like watermelon versus rice, or when protein, fat, and fiber dominate. And that's a critical piece of the puzzle as well. So when we're looking at clinical outcomes,

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I've got to say the research is really mixed. You will see some research saying that glycemic index response can predict or can improve some health outcomes like insulin sensitivity and weight loss. But you've got other trials like the Omnicarb trial didn't really improve insulin sensitivity. And sometimes even at that population-based level can change other metabolic health markers and potentially unfavorably.

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In diabetes care, meta-analysis shows modest HbA1c benefits for low GI-GL patterns. So it might be helpful, but I would say it's just not a magic bullet. So if you are looking at the glycemic load, the best thing in glycemic index and wondering what you should do, then essentially one of the best things to do is to actually do a little bit of self-experimentation. So look at the...

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available carbohydrate, look at the glycemic load of a particular food and assess how it affects you. And you might do this through a glucometer, so using like a finger prick, or you might do it using a CGM. And this is where I think it can be super helpful and interesting, right? Like we are our own best science experiment, much, you know, like what we find out about how we respond to food is actually way more important than what like a value on a packet is.

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for glycemic index or what the research might tell us about how certain individuals respond. Why does that matter? What matters is how you respond. So what you can do is test how you respond against different types of rice, like basmati versus jasmine rice, for example. Both of them are quite high in both the glycemic index and glycemic load, though basmati comes in a little bit lower. So just test to see how, you can, you know.

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notice a change in your hunger or appetite when you have these different types. How does it change if you add a little bit of vinegar to it or if you have smaller amount or if you cook and cool it because rice also has that change in that resistant starch. Same thing with oats. Does it make a difference if you choose steel cut which are bigger particles versus instant which are smaller and easier to digest. There is certainly a difference in both the glycemic index and the glycemic load. Like the glycemic load goes from

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high to low when you use the 40 grams of steel cut versus instant oats. Similarly with pasta, you know, like if you do it al dente, you do get a one cup of cooked has maybe 40 grams of carbohydrate. And if you do it al dente, so firm to the bite, that actually is, it's medium on both glycemic index, but it's a little bit lower on both glycemic index and glycemic load, al dente versus being very soft. And that

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could make a difference to your blood sugar. Similarly with sourdough versus soft white bread, sourdough has that fermentation, the more acid, acidic type preparation versus just soft white death. Just kidding, white bread isn't white death. But it does make a difference and your glycemic load is a little bit lower. Interesting though is what you want to do is practically speaking, you want to find staple carb options that give you lower spikes

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with better satiety and energy, if you're looking at your continuous glucose monitor. It's not about zero carb, it's not about zero spikes, but it is about what gives you an appropriate blood sugar response that allows you also to maintain good energy and good satiety across the day. That's really what you're looking for. Interestingly, there was this Israeli study in 2015, ZV et al, that looked at personalized nutrition by prediction of glycemic responses, and what they found was

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pretty interesting. So they used CGM to determine how does a banana affect a certain individual? How does a cookie affect a certain individual? What about ice cream? And what they found was there was real variation. Like some people absolutely did not spike at all to banana. Some people shot up and then went straight down again. Similarly with a cookie, a cookie really kept a flat line for some people, whereas for others shot it up and put it straight down. And I guess this just goes to illustrate that no food is

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quote unquote, good or bad, depending on its glycemic index or what it looks like. Like this is just one measure of how you can determine how helpful a food might be for you. Because obviously cookies aren't healthy. Sorry, I mean, I know that's really unpopular to say, but it is actually the truth. Whereas a banana for some people is healthy, but for others actually, it's probably not a good choice if it's gonna spike your blood sugar up and leave it sort of down. So these are just some things to sort of think about. So if something's a low GI,

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doesn't necessarily mean it's healthy because ice cream can test low, but it's because of the fat content in it. So it's just one major measure of food. And also high GI fruit isn't necessarily a bad thing either. Watermelon being case in point, full of water. It's got a high GI, but you have to eat a truck of it to actually get that 50 grams of carbohydrate. not everyone should try and aim for low glycemic load across the board. It is such an individual thing that you just want to

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think about your own personal glycemic responses. And that's the most important thing. So glycemic index, I don't think is very useful actually. Glycemic load tells you a little bit more of the story, but it's a glycemic response is where you really want to dial in what works for you and what doesn't. That does take a little bit of work at your end and you're not just going to find that information in a research paper on some sort of bread packet or anything like that. So, or in a database. So.

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There you go, just a little spell on glycemic index, glycemic load, glycemic response. Hopefully that was helpful. Let me know. You can find me on Instagram @mikkiwilliden, Facebook @mikkiwillidenNutrition. Head to my website, mikkiwilliden.com, book a call with me. And we can talk more about this. All right, team, you have the best week. See you later.