by Collin Stark March 25, 2022 8 min read
With there being so many different “diets” or lifestyles out there, "low-glycemic" is another one you may have heard of.
Knowing more about it, and what a low-glycemic diet is, will allow you to decide if it is something you should focus on.
To help you answer this question, you need to understand what the glycemic index of food is, and why you would want to consider being on a plan that follows it or not.
The glycemic index (GI) is a system developed in the early 1980’s by a man named Dr. David Jenkins, and that system is a way to rank carbohydrate-containing foods based on how much they affect the levels of glucose in the blood after they're consumed.
Glucose is a very simple sugar, and it's what all carbohydrates break down into once digested ... no matter how complex the carbohydrate source is. It is the main fuel source used by our muscles and brain every single day.
I know you may have heard that sugar is bad ... and when consumed in excess, I would agree.
However, it can be part of a healthy, balanced diet to allow us to live and perform at a high level.
The thing is, not all carbohydrates are met with the same response in the body once they're ingested.
Common sources of carbohydrates are breads, cereals, pastas, fruit, vegetables, grains, etc. Once they're ingested, the rate at which blood glucose levels increase is measured, recorded, and assigned a ranking based on that measurement.
All foods in the glycemic index scale are given their ranking by comparing them to ingesting 50 grams of pure glucose (GI value of 100) as a reference point and seeing how much their levels rise in the blood in comparison.
Low GI value: 55 or less
Moderate GI value: 56-69
High GI value:70 or more
The higher the GI number, the more blood sugar numbers rise after ingestion. The lower the GI number, the less blood sugar levels rise.
This means if you’re wanting to follow a low-glycemic diet, then you are ideally ingesting mostly carbohydrates that break down slowly and don’t spike levels of sugar in the blood (aka foods with a lower GI value) rather than foods that breakdown and are absorbed very quickly (foods with a high GI value).
This is generally true for many people with diabetes, PCOS (polycystic ovary syndrome), someone who suffers from insulin resistance, or anyone that has trouble keeping their blood sugar levels from getting too high and staying there.
First, I think it is valuable to know how digestion works.
The digestion of carbs actually starts in the mouth, with enzymes that specifically help break down carbs.
Then, after we swallow the carbs, they go into our stomach where they're further broken down before entering the intestinal tract. This is the main step where the carbohydrates are absorbed into the bloodstream at differing rates.
See, the simpler the carb, the less "effort" it takes for the body to break down. This means it's absorbed into the bloodstream more rapidly, while also raising blood glucose levels.
The more complex the carbs, the slower the breakdown and digestion ... meaning they're absorbed into the bloodstream at a slower rate which is less impactful on blood glucose levels.
Above, I mentioned both “simple” and “complex” carbs ... but what does that mean?
A simple carb is made up of fewer and smaller molecules, and since every carb is broken down into glucose, this process can happen faster and is “simpler.”
Complex carbs are made of longer and larger molecules, which cause your body to break them down slower, since the conversion to glucose is more “complex.” This slowing of the breakdown is what alleviates some of the spike in blood sugar levels.
The type of sugar in the food could make it more high-glycemic or low-glycemic.
A common misconception is that ALL sugars cause a rapid increase in blood sugar, but this is not true. For example, bananas contain glucose, fructose, and sucrose (a glucose and fructose molecule that are bound together).
We already know that glucose has a GI value of 100, but what about fructose and sucrose? Fructose has a GI value of 23, and sucrose 65. Not all sugars produce the same rapid increase in blood sugar that glucose does.
Another factor is what else makes up the carb source outside of the carbohydrate content itself.
White potatoes and sweet potatoes contain similar amounts of starch (carbohydrates found in most plants), but sweet potatoes contain more fiber (a type of carbohydrate the body has trouble digesting) so it breaks down slower than white potatoes and has a lower GI value.
A white russet potato has a GI value of 111 which is higher than glucose itself, whereas a sweet potato has a GI value less than half, at 54.
Carbohydrate sources mixed with other protein and fat sources will also slow the digestion and absorption of the carbohydrates ... and thus, lower their GI value as well.
Another major factor that is often overlooked is the level of processing/refining of the carbohydrate, and the fact that how long it's cooked affects the GI value.
Generally, the more processed the carbohydrate is, and the longer it is cooked, the higher the GI value ... since the processing/cooking is breaking it down more before eating.
This makes it easier to digest, and quicker to absorb ... raising the rate at which glucose levels rise in the blood.
Studies show that in America, roughly 1 in 10 people have diabetes, and 20% of those who have it don’t even know that they have it.
Also, 6-12% of women in the US of child-bearing age have PCOS. These conditions can affect how well our body controls blood sugar levels.
In many cases, if blood sugar levels stay elevated for too long, it can increase chances of many issues ... such as increased rates of obesity, cardiovascular disease, nerve damage, kidney damage/failure, and even damage to the blood vessels in the retina, which can lead to blindness, and more.
It’s important for many individuals with these conditions to be on a low-glycemic diet to control their blood sugar levels, but that’s a conversation to have with your healthcare provider if you are not sure if it is necessary for you or not.
Those are just 2 conditions that would warrant someone to want to be on a lower-glycemic diet to maintain optimal health, since their body has trouble lowering blood sugar once it is elevated.
There are other reasons as well. Many people with conditions such as high cholesterol are overweight, obese, or have a higher risk of certain cancers or cardiovascular disease. In these cases, they could benefit from eating a low-glycemic diet as well.
At this point in the blog, you should have at least a basic understanding of what the glycemic index is, and that certain foods affect your blood sugar levels more than others. So now, it is important to understand the correlation of insulin as well.
Insulin is a hormone our pancreas secretes when there are elevated levels of sugar in the blood. The level of elevation is what dictates the insulin response.
What does insulin do? Insulin actually helps transport nutrients into cells by signaling the cell to “open.”
So, why wouldn't we want insulin levels to be elevated all the time? Well, our cells can become desensitized to insulin and actually less efficient at absorbing those nutrients over time.
When this happens, our blood sugar levels have a harder time coming back down after being elevated, because our cells aren't “open” to absorbing the sugar like they normally are.
Another thing to consider is that insulin inhibits the breakdown of fat or lipolysis. So, if you have elevated blood sugar levels and elevated insulin levels for extended periods of time, this could lead to a more difficult time losing fat, and possibly even gaining unwanted fat.
If you have a little extra body fat that you’d like to get rid of, you could look into doing a low-glycemic diet.
There are a lot of individuals that struggle with their weight these days, and a possible culprit could be a diet with too many high-glycemic foods, meaning sugars and other highly-processed and refined carbohydrates.
In addition, when high-glycemic carbohydrates are eaten, they cause a rapid rise in blood sugar, as discussed earlier in this blog.
This causes a spike in insulin (the storage hormone meant to lower blood sugar when it gets higher than our baseline), and this rapid drop in blood sugar can cause low energy and increase hunger.
That hunger and lack of energy can possibly lead to grabbing more sugar and simple carbs. This can lead to increased caloric intake, and in turn, can lead to weight gain.
Keeping your diet lower in high-glycemic foods can help minimize this effect, and help you in your efforts to lose weight as long as a reduced calorie diet is also being followed.
• Fiber one
• All bran
• Oat bran
• Kidney beans
• Pinto beans
• Whole wheat tortillas
• Whole wheat pasta
In the post-workout setting, it's actually beneficial for your body to consume high-glycemic carbohydrates, whether you're working toward losing weight or not ... especially after resistance training.
During resistance training, your body is using plenty of energy to perform optimally in your workout, and the energy source is a stored carbohydrate in the muscle tissue and liver, called glycogen.
Glycogen is a multi-branched molecule made up of multiple glucose molecules bound together and stored for when we need it during physical activity. This gets depleted throughout the training session along with micro-tears being made in the muscle tissue itself.
After training is finished, the body is in a state of having depleted fuel and damaged muscle tissue. In order to fully and optimally recover and be ready for your next workout, it is quite beneficial to replenish that fuel and repair the damaged muscle as soon as possible.
In order to rapidly and efficiently replenish glycogen, you will need glucose ... and since that will cause a high-insulin response, this will signal the muscle cell to allow the glucose to enter.
The higher glycemic the carbohydrate source is, the higher the insulin spike, and the faster the glucose can get taken into the muscle cell to replenish glycogen.
In order to repair the damaged muscle tissue from that workout, you will also need a protein source with a sufficient amount of essential amino acids to spike a process called muscle protein synthesis.
To get that protein into the muscle, it also requires that insulin spike to enter. So with a fast digesting and high-glycemic carbohydrate source being used to spike insulin ... it only makes sense to add in a rapid-assimilation protein.
This protein will digest quicker than whole food protein sources, so it can ride that same insulin spike into the muscle cell, start the repair process of the damaged muscle tissue, and replenish the glycogen stores as fast as possible.
This is an extremely fast and efficient way to kick-start the recovery process, and will deliver highly favorable results.
Now you understand more about how low-glycemic foods can be beneficial to keep in your nutrition plan...
As well as how high-glycemic foods can also be helpful in certain scenarios.
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