One important information to consider when researching different types of food is both the GI and the GL. Both are information that can be easily found on the Internet. GI (glycemic index) means how fast the blood glucose can rise after eating, and the GL (glycemic load) is based on the total amount of carbs in the food, which determines how long the spike will be. The more refined a food is and the longer it is cooked the highest will be the GI.
The GI is a scale that goes from 0 to 100. Zero would mean that the food doesn’t raise the blood sugar at all (the list includes basically only water) and 100 means that the food raises the blood glucose as much as pure glucose (which is the theoretical maximum). Foods with a low GI (less than 55) raise the glucose gently, while foods with a medium (above 55) or high GI (above 70) cause violent spikes of glucose and insulin that can be harmful.
Foods with high GI causes huge spikes of insulin, leading to weight gain, binge eating, and so on. If consumed regularly they increase the risk of diabetes and other diseases. Whole grains, for example, have a much lower GI than refined grains, and refined grains, in turn, have a much lower GI than flours and starches. Foods that are low on carbs also tend to have a lower GI (legumes have much lower GI than grains, for example) and fibrous vegetables like kale and cauliflower as well as most other vegetables and greens have very low GI. This is another reason why we should eat more vegetables and less grains.
Another point is that not all carbs are created equal. Once I was checking the nutrition facts of chia seeds and noticed something very strange: although 100 grams of chia seeds have 41.2 grams of carbohydrates, it’s GI is just 1 (one!) with a glycemic load of also one. This is much lower than even lettuce, that has a GI of 15, or kale (that has a GI of 4).
At first I thought it must be a mistake, but after checking other sources I saw it was actually correct information. How can this be? The answer, I found out, resides in the difference between starches (and other types of carbs) and soluble fibers. Although counted as carbohydrates in the nutrition tables, soluble fibers are a completely different animal.
Different from insoluble fibers (like the ones present in wheat bran and in the skin of fruits and vegetables, for example) that are just a type of bulk that is not absorbed by the body at all, soluble fibers do get digested and converted into energy, generating about two calories per gram.
However, instead of being converted into glucose, like in the case of simple starches, soluble fibers are complex starches that our bodies can’t directly digest: they can only be digested by the bacteria living in the gut. They slowly convert the soluble fibers into short-chain fatty acids, a very healthy compound that reduces the risk of inflammatory diseases, type 2 diabetes, obesity, heart disease and other conditions. Not only that, but it can be very easily absorbed by the body and converted into energy. In other words, the soluble fibers feed the good bacteria in the gut (that’s why they are also called prebiotics), and they reciprocate by giving us a lot of different health benefits and also a stable supply of energy in the form of these fatty acids.
Due to this particularity, soluble fibers don’t raise the blood sugar and don’t provoke the release of insulin at all. Quite the opposite: they make the absorption of sugars and staches much slower, and therefore contribute to reducing the GI and GL of other foods that you may eat alongside it.
From the 42.6 grams of carbs present in 100 grams of chia seeds, 34.4 are soluble fibers. Therefore, although it also has 8.2 grams of other carbs, the presence of the fiber makes the absorption so slow that it doesn’t raise the blood sugar at all.
One of the secrets of good health is to minimize the ingestion of foods rich in simple carbs (like rice, wheat, corn, etc.) and to increase the ingestion of foods rich in soluble fibers, like most vegetables, berries, nuts, barley, oats, lentils, avocados, etc. and to always combine high glycemic foods (like rice or potatoes, for example) with ingredients that are rich in soluble fibers, creating a package.
It’s difficult to overstate the importance of good gut bacteria for our health. Not only do they help with the digestion process and protect us from the proliferation of bad gut bacteria, but they produce a good chunk of the vitamins and other important nutrients that the body needs.
In the Ayurveda it is mentioned how vitamins are created by the fire of digestion. It may seem absurd at first, but it’s actually scientifically correct. The digestion process in fact produces vitamins and other compounds that are not originally present in the original food, and the only reason this happens is because of good gut bacteria.
One who has his population of good bacteria destroyed due to a bad diet or the use of antibiotics can have all kinds of problems, not only related with digestion. An imbalance in the gut bacteria can affect even our mood, ability to focus and productivity. That’s yet another reason why soluble fibers are so important.
Finally, there are the resistant starches, that can be considered a third type of fiber. The main characteristic of this type of starch is that it’s resistant to digestion. As a result, it’s digested slowly, also not contributing much to raise the blood sugar. Resistant starches are found in legumes, certain grains (like barley and oats), seeds, roots, etc.
The problem with resistant starches is that they can be easily converted into simple starches if they are heated for long enough. The higher the temperature, and the longer the cooking, the more they break down, resulting in a progressively higher GI and GL.
Potatoes, for example, are normally accepted as a starchy food. However, raw potatoes are actually very rich in resistant starches. If one would eat raw potatoes (this is not recommended, due to the antinutrients, but just for the sake of example), it would not raise the blood sugar at all, almost like chia seeds. When potatoes are boiled, the GI rises to 59 (or 78 if mashed), but if they are baked, it rises to 85! Cooked sweet potatoes have a GI of 44 (lower than white potatoes) but when baked their GI skyrockets to 94, almost as high as pure glucose.
From this, we can see that not just the individual ingredients, but also the way they are combined and prepared, should be taken into consideration. In general, the more the food is cooked and crushed into small particles, the higher their GI becomes. That’s why, as far as possible, we should try to take grains and tubers as close to their natural state as possible, cooking for a shorter time, and prefer whole grains instead of polished or refined options.