Reactive hypoglycemia, or low blood sugar, is a condition in which your blood sugar falls into a range that is too low to support your body’s needs.
This type of hypoglycemia generally occurs about 2-4 hours after eating a high carbohydrate meal or food. Your symptoms may include dizziness, lightheadedness, flushing and shakiness. Eating some sort of carbohydrate (sugar or starch) usually relieves the symptoms.
Some physicians believe the cause of reactive hypoglycemia is a consequence of the excessive amounts of insulin the body releases in response to a high carbohydrate meal. In other words, more insulin is release than needed, and blood sugar is driven much lower than needed.
But reactive hypoglycemia can also happen if your body burns glucose too rapidly, or if your digestive process is too slow in releasing the sugar from a meal into the bloodstream.
A diet which is chronically high in carbohydrates can also trigger hypoglycemia. What is too high? Consider the fact that the entire human body has a total of 1 teaspoon of sugar in use at any time. That's all - 1 teaspoon or 4 grams of carbohydrate. Now contrast that to the fact that one slice of bread has 25 carbohydrates in it. That's over 6 teaspoons of sugar when broken down in the body. Eating one slice of bread dumps more than 5 times the amount of sugar needed into the body. And worse, a can of soda has about 50 grams of sugar - 10 times more than the body needs.
How is Insulin Involved in Low Blood Sugar?
Insulin’s job is to get the sugar from your meals out of your blood stream and into your cells where it can be used to fuel cellular processes. If you eat a meal which is high in carbohydrates, your body releases a great deal of insulin to route all that sugar into your cells. Sometimes, the body releases too much insulin, and ends up driving too much sugar out of the blood, and causing a low blood sugar reaction.
But there is more to the story, and it has to do with insulin and blood sugar levels over time. When carbohydrates are available to burn as fuel, your body stores any fat that comes into the cell for future use.
This biological process is a necessity from our evolutionary history. When humans lived as hunters and gatherers, food was not available regularly, so the body had mechanisms in place to provide energy to hunt and travel, even when food was unavailable for several days. After going a day or two without food, our bodies begin burning stored fat for fuel instead. Biochemistry books call this this body phenomenon the "fasting" state.
The body prefers to store fat for fuel because fat is nutritionally dense, and provides more than double the amount of calories as carbs or protein.
The body can’t store very much sugar or glucose at one time. Sugar is stored in small amounts in your muscles and liver as glycogen. In the average human body, there’s only about 1600 calories of glycogen stored at any one time. In comparison, it takes about 2500 to 3500 calories to fuel a human body for one day.
So as you can see, if the body had to rely on stored glycogen, it would only have fuel to go for about half a day of normal activity. After that, there would be no more energy to do anything, much less run after an animal and kill it for food.
Now fast forward to today. Food is available all the time, and much of what we choose to eat is carbohydrate based. To the body, any carbohydrates, whether refined or whole, are basically sugar. If these foods are available, the body, because of its evolutionary bias, will use carbs for fuel over stored fat.
When a high carb diet is consumed every day over a long period of time, the body is constantly called to release a great deal of insulin to counteract the consumed sugar.
Eventually, because so much insulin is constantly circulating in the blood stream, the body gradually becomes "resistant" to its message. It becomes more difficult for insulin to do its job of moving sugar into the cells. The average levels of insulin and blood sugar begin to rise and become chronically elevated.
At this point, your doctor may tell you that you have become "insulin resistant" and that a blood test called HbA1c is elevated. This test is a measure of your average blood sugar levels over the past 4-6 weeks. More than likely, your LDL cholesterol and your triglycerides will also be elevated, and your HDL cholesterol will be too low.
The bottom line is that as long as insulin and blood sugar levels are higher than normal, the body will store fat instead of burning it for fuel.
So, what does this all have to do with reactive hypoglycemia?
Another Cause of Reactive Hypoglycemia
In my experience, reactive hypoglycemia can also happen when you first begin a low carb diet.
One of the benefits of eating a low carb diet is to lower your average blood sugar and insulin levels, and to retrain your body to burn stored fat as fuel.
As discussed above, during the time that you have been eating a high carb diet, your body has become used to a higher level of circulating insulin and higher levels of carbs available to turn into sugar for fuel.
When you are insulin resistant, your body is used to releasing a certain amount of insulin in response to each meal you eat.
To oversimplify, your body "expects" a certain amount of carbohydrate will be consumed, and it dumps what it thinks is the right amount of insulin for that amount of carbohydrate consumption.
But you’ve thrown your body a curve ball, and you’ve gone a couple of days eating meals which are very low in carbohydrate.
Your body gets by for a couple of days by using the stored glycogen in your liver, and continues to release the same amount of insulin. But eventually, the glycogen runs out, more insulin is released than actually needed, and a couple of hours later, you have a severe episode of reactive hypoglycemia.
The symptoms of a reactive hypoglycemic episode may include:
Generally, eating something that is high in carbs, like juice or candy, relieves the symptoms after about 20 minutes. Eating 3-4 glucose tablets are an easier way to relieve the symptoms.
How to Avoid Reactive Hypoglycemia
The best way to avoid reactive hypoglycemia is to permanently reduce the amount of carbohydrate that you consume. This will eventually lower the amount of blood sugar and circulating insulin, and your body can then "remember" to burn fat for fuel instead of sugar when in a fasting state.
During the first phases of going low carb, it’s also a good idea to make sure you eat every 3-4 hours. Until you can retrain your body to burn fat, don’t try to go for more than 4 hours without food. Interestingly, however, some people who have experienced ongoing hypoglycemic reactions report that waiting 5-6 hours before the next meal actually helps reduce the reactions.
You can ask your physician to schedule you for a Glucose Tolerance Test with Insulin to test for the presence of too much insulin. In this test, after fasting for at least 8 hours, you are given a certain amount of glucose to drink, then your blood sugar and insulin levels are measured every hour or so.
If the test reveals that your blood sugar is lower than it should be several hours after consuming the glucose solution, it may be because your insulin response is too high.
Be aware that mainstream physicians aren’t generally knowledgeable about this condition because it is rooted in nutritional causes. Doctors aren’t taught about the power of nutrition, and so he or she may minimize your concerns about it.
But if you having these reactions, it may mean you are on a path to diabetes, even if your fasting blood sugar is normal. So find a physician who will help you, if your physician won’t.
You may have to reduce your carbohydrate consumption slowly over a period of time to minimize these reactions, but eventually, by eating a diet lower in carbohydrates, you should be able to avoid reactive hypoglycemia completely.
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