Carbohydrates and their effect on blood sugar are among the latest “hot topics” in health, wellness, and even sports performance. Every week there is a new article extolling the benefits of a high fat diet or bashing those experts that still have the gaul to recommend sugars to aid in performance. Surely a low carbohydrate, high fat diet (dubbed LCHF) is now the only way to go! Well…not so fast.
In medicine and performance, new trends come along all the time. A promising theory and a few early studies can lead everyone to jump on the latest fad, regardless of whether they understand the subtleties. Let’s take a step back and examine this one, and we’re going to use a new tool to do so.
Unfortunately, nutrition tends to fall into the same category as politics and religion. It generally should not be the topic of conversation among people with whom you hope to remain friends. However, rather than looking for a “right” or “wrong” on this topic, I want to examine some specifics that tend to be dependent on situational and individual variation. In other words, let’s look at the nutritional shades of gray. Nutrition is not black and white, and if anyone tells you that you “must” adhere to any one diet, you should probably look elsewhere for advice.
In this article, I’m going to take a look at glucose metabolism with regard to both overall health and athletic performance. Some will say that optimal health and maximal performance cannot coexist, but I disagree. The goal of this post is not to delve deeply into the science. We’ll touch on big concepts, but there are many other resources available if you want to examine physiologic processes and mechanisms.
As a quick and basic primer, here is a brief overview of what occurs in your body when you eat carbohydrates. As the food is absorbed, the glucose (or “sugar”) levels in the bloodstream increase. Your pancreas then secretes a hormone called insulin, which is necessary to move that glucose into the cells of the muscle and liver, where it is stored as glycogen. When excessive carbohydrates are consumed, insulin levels must remain high. If this occurs for long periods of time, the body becomes less responsive to insulin, requiring more of this hormone to do its intended job. It’s a vicious dietary cycle. To add to this, insulin can have a very inflammatory effect, especially if it hangs around in large quantities for extended periods of time. To be clear, insulin is not bad! It serves a very important purpose as an anabolic hormone, but anything in excess can be problematic.
With regard to overall health, it is now well-established that excessive sugar and carbohydrate intake can cause significant problems. Diabetes, neurologic diseases, dementia, and even some cancers can be caused or hastened by dietary carbohydrate intake. But this is not a binary issue. A person with Type II diabetes (characterized by severe insulin resistance) is not “healthy” up until they are diagnosed as diabetic. Often this diagnosis is preceded by years of insulin resistance and other symptoms of “metabolic syndrome”. As with many such chronic conditions, this is one which brews for years until the body is no longer able to compensate. Excessive carbohydrate intake leads to excessive insulin excretion. As more insulin circulates at chronically elevated levels, your body develops a resistance to this important hormone. This leads to impaired ability to metabolize carbohydrates, as well as a concurrent increase in inflammation. While physical activity helps to slow and off-set this process, exercise is not entirely protective. Don’t get me wrong, exercise is requisite for health! But as they say, you can’t outrun a poor diet.
Glucose metabolism is a key component of athletic performance as well. Carbohydrates are an important source of fuel when exercising or competing. If your diet is inappropriate for your activity level, your performance will suffer. If you have a diet which is extremely high in carbohydrate, you may have difficulty efficiently accessing fat stores for fuel when undertaking easier, endurance-type efforts. Conversely, if you excessively limit your carbohydrate intake, you run the risk of exhausting your glycogen stores. This could lead to poor performance at higher intensities, and chronic depletion may lead to hormonal dysregulation and symptoms of Overtraining. Like most things in medicine and science, the answer does not lie in the extremes. Balance is key, and finding your own, individual balance is crucial to optimal health and performance.
This is Part 1 in a 3 part series. Stay tuned to learn the specifics of how you can determine your ideal individual diet and fueling strategy.