The glycemic index was never meant to advise us on what foods are healthy. It just turned out that foods high in sugar have higher GIs than foods with sugar that absorbs more slowly. Well DUH! The glycemic index is a ratio between how high a food spikes your blood glucose in reference to pure glucose. Whether you eat a complex carb or a simple carb, your body breaks it down into its constituent sugars. If you eat real foods and balanced meals, you will never have a problem with this. If you munch on sugary snacks all day long, well, you’ll have problems eventually. In this post I will share 5 common myths surrounding the glycemic index and what you need to know about making truly healthy decisions.
1. Low GI foods are healthier
Most discussions on this issue turn into a quest to find lower GI foods, with the mistaken belief this will lead to weight loss and that this always results in better health. The fact is that when you eat a balanced meal, with some fat, carbohydrate, and protein, the overall meal will have a low GI. The more important question is: “what are you actually eating?”
This is important because it’s easy for the health conscious consumer to become overly fixated on one particular estimate or facet of the health equation and forget the bigger picture. In turn, this person avoids foods they actually want to eat, because of some idea that was never meant to be. The glycemic index was never meant to tell us what foods are healthier than other foods. It’s a simply a tool to compare how a food containing carbohydrate increases your blood sugar relative to pure glucose.
2. High GI foods are unhealthy
Again, the GI is a RATIO between how high a certain food increases your blood glucose compared to pure glucose alone. Therefore, a high GI food results in your blood glucose levels being elevated more than lower GI foods over a period of two hours.
Watermelon has a relatively high glycemic index. Should we stop eating watermelon? I crave watermelon on hot days when I’ve moved around a lot. Oh yea–movement! That will affect your insulin sensitivity too. If I sit around all day and eat massive quantities of watermelon, well that wouldn’t be good; but more importantly, why would I want to anyway?
See, sometimes, our cravings tell us what we want. Nutrition studies don’t measure this, unless we’re talking about retrospective cohort studies. But if we give everyone the same food (which is what’s done in a glycemic index study), we’re not taking into account people’s natural preferences for that food when observing the effects of eating that food. Avoiding high GI foods like watermelon isn’t going to make you healthier. Eating what you really want, and emphasizing whole foods and ancestral wisdom will.
3. Rice has a high glycemic index.
Wrong. I talked about this previously, but white basmati rice is one of the few varieties that actually has a low glycemic index. White rice ranges from being a low GI food to a high GI food. For brown rice is the same, although it’s slightly higher due to the longer cook time.
The same goes for potatoes. Baked potatoes have a lower GI than boiled potatoes. Cooking method influences GI a lot. I’ll mention that in a future post.
4. The glycemic index is a fixed number.
Whenever someone cites an exact number for the glycemic index of a food they are wrong. There is no exact glycemic index of a food, because that depends on your individuality. Don’t believe me? Read this post, that explains exactly how glycemic index studies are performed.
The glycemic index is an estimate based off of a small number of participants (usually 10). But using the article “the” in front of the term makes it sound like it’s one fixed thing. Nope. A single food does not have a fixed glycemic index, because it depends on how you digest it. This factor of individuality is completely missing from most of our discussions on nutrition. As I’ve discussed previously, some people see their glucose go up more in response to sourdough bread than white bread, and this depends on one’s microbiome. In the study discussed in that post, white bread, which is traditionally thought to have a GI, was proven to be a factor of the bacteria in someone’s gut. Now that changes up everything. If this is true for other foods, then most of what we think we know about the glycemic index is incorrect.
And as I talked about in a YouTube video, Asians see a greater rise in their blood glucose than Europeans in response to rice (about 60% greater). This doesn’t mean it’s going to cause diabetes in Asians–no. Maybe they just break it down faster because they’ve been eating it consistently and for much longer than Europeans have. That’s just my hypothesis. The glycemic index is simply a tool useful to compare foods against one another in a small number of subjects.
5. The glycemic index applies to all foods
The glycemic index is only relevant to foods that contain a lot of carbohydrates. It’s irrelevant for foods that are richer in fat and protein and nearly devoid of carbs like meat. This doesn’t mean those foods don’t raise your insulin levels, it just means that they don’t even get measured in glycemic index studies. This is because to determine glycemic index, enough of a food must be consumed to supply 50 grams of carbohydrate from that food. So for meat, which contains little to no carbohydrate, a massive quantity would have to be eaten to determine what’s happening. Of course, we could just ingest a serving of meat and measure our blood glucose afterwards. Most likely, there wouldn’t be much of an effect but you never know.
Don’t worry about high GI foods. All that means is that it contains rapidly digestible glucose, not that it will give you diabetes. If you regularly exercise, foods with a lot of glucose are good for recovery. It’s why I crave carbohydrate-rich protein shakes after a workout!
And of course, if you eat a balanced meal, your blood sugar levels aren’t going to spike upwards very high immediately. You can probably tell when they do anyway, as you’ll notice a blood sugar crash, and perhaps some sleepiness, but symptoms like that are highly variable.