Carbs
The next few newsletters I will be doing will be about the different macronutrients. This week I will be focusing on carbohydrates. I think it is important to have a baseline understanding of different macronutrients and what they are used for. With a good baseline understanding, you will be able to start formulating your own opinions about different diets. Keep in mind that the information I’ll be providing is just that, a baseline. I will do my best to keep everything simple and easy to understand. I hope I remind you of a few things you already know, and maybe a thing or two that you didn’t know. As always, I’ll have the sources below if you want to dive deeper into any of these topics and need a place to start.
What is a carbohydrate?
Starting off, a carbohydrate (or carb) is one of the four macronutrients (fats, proteins, carbohydrates, and alcohol) that can be found in food and drinks. Carbs fall under three categories: starches, sugars, and fiber. Starches and sugars provide 4 kcals of energy per gram. These carbs are broken down by the body and turned into glucose. Glucose sits in the bloodstream and is used as quick energy. Excess glucose, that is not used as energy, is stored as fat.
Our body prefers to use glucose as an energy source if it is available. It is quick to breakdown and has little waste products, as opposed to using fats for energy. Even though our body prefers to use carbs for quick energy, carbohydrates are not essential for bodily function. Our body really only needs fats and proteins (on a macronutrient level) to function. Even though carbs are not essential, carbohydrates are not the enemy. For many people, carbs are essential to maintain optimum performance and health.
To help understand when our body wants to use carbs and when our body wants to use fats for energy, we can look at the below graph. The red line (FAT) represents the percent of energy coming from fats and the blue line (CHO) represents the percent of energy coming from carbs. Moving left to right on the graph represents an increase in relative exercise intensity. So, at rest (low exercise intensity), our body likes to burn more fats than carbs for energy. At a moderate workout intensity (heart rate approximately 120 beats per minutes or a light jog/bike ride) our body wants to get about half of our energy from carbs and half from fats. Finally, at the most extreme workout intensity (40 meter sprints or max effort squats) our body wants to burn primarily carbs and no fats.
This is important to understand when you make your own decisions about how many carbs to consume. From a performance standpoint, carbs can help you get quicker energy when you are working out at a high intensity. From a quality-of-life perspective, you might feel better consuming a certain amount of carbohydrates every day. How many carbs you consume is completely dependent on what works for you and what you need. However, not all carbs you can consume are created equal.
The first category of carbohydrates I want to talk about is fiber. Fiber is an indigestible complex carb that is found in nuts, grains, fruits, and vegetables. It is not found in any animal products. Since fiber is indigestible, it does not provide any energy to the body. However, fiber aids in digestion of other nutrients and is a critical component of processing cholesterol.
Starches are another usually, but not always, complex carb. Starches are found in many of the same foods that contain fiber. Starches can be found in many vegetables, fruits, grains, and nuts. These complex carbs take longer to break down and provide a slower release of energy.
Our last category of carbs are sugars. Unlike the other two types of carbs, sugars are simple carbohydrates. Sugars can be found in many refined foods as well as naturally in fruits and milk. Simple carbs are broken down very quickly by the body and provide a faster release of energy.
Glycemic Index
The glycemic index is a tool that is used to help us quickly gauge how fast a food is broken down into glucose in the blood stream. The glycemic index gives a food a score from 0-100. The higher the score, the quicker the food is turned into glucose (100 is pure glucose) in the bloodstream. This is where the idea of complex and simple carbs come into play. The more complex a carb is, the slower it is turned into glucose and it’ll have a lower glycemic index. In contrast, the simpler a carb is, the quicker it turns into glucose and it’ll have a higher glycemic index. Below is a picture giving scores to common foods consumed by Americans.
The glycemic index tells us how quickly something will spike our blood sugar but doesn’t tell us how high it will spike our blood sugar. To know that, we need to look at glycemic load. Glycemic load factors in both the glycemic index and the amount of carbs in a serving of a food. The higher the glycemic load, the greater the spike in blood sugar will be. For example, one ounce of watermelon has a glycemic load of 41 and a glycemic index of 72, but one ounce of a chocolate bar has a glycemic load of 236 but a glycemic index of 49. The glycemic load of foods has a greater impact on our health than its glycemic index.
Glycemic load directly impacts how high our blood sugar spikes. Our blood sugar levels directly tell our body to release many different hormones, including insulin. I’ll explain insulin more in another newsletter, but for our understanding of carbohydrates, it is important to know a few things about insulin. Insulin is one of the most anabolic (energy storing) hormones released by the body. The higher the blood sugar levels, the greater the release of insulin. Chronic release of high levels of insulin can create insulin resistance. This is a leading cause of type two diabetes, obesity, and high blood pressure. Having a balanced diet of complex and simple carbs can help minimize the risk of building insulin resistance.
Artificial Sweeteners
The correlation between high consumption of simple carbs and insulin resistance; lead researchers to the create artificial sweeteners. The goal of artificial sweeteners is to still satisfy the oral sweet taste receptors but provide little or no calories. There are wide variety of artificial sweeteners, some coming from natural sources (stevia) and others artificial sources (aspartame and sucralose). However, the research is still undecided on the efficacy of artificial sweeteners.
The best way I had artificial sweeteners explained to me was back in college. Here is the oversimplified version of that. Think of the wall of our digestive tract as a fence between our digestive tract and bloodstream. In this fence there are many different “gates”. As food enters our stomach, our body senses the presence of the macronutrients that make up that food. Our body then makes gates to allow that food to be absorbed and pass through the fence. The number of gates and type of gates impact how quickly something gets absorbed. Our body is so good at prepping our gates for absorption that it will start producing them from preliminary senses like taste and smell. This is where artificial sweeteners come into play. Since artificial sweeteners mimic natural sweeteners (sugars) and our body reacts the same way. It is possible that some artificial sweeteners create the same gate-opening-response that normal sugars do. When artificial sweeteners are consumed, with no actual carbohydrates, it has potential to leave our body in confusion. Our body created the gates for absorption, but had no actual blood sugar increase. If an artificial sweetener is consumed with carbohydrates, there is evidence that there is a greater insulin response to that carbohydrate compared to consumption without it. So, when an artificial sweetener is consumed with carbohydrates it could cause an increase in glycemic load. This is just one possibility of what is happening when we consume artificial sweeteners. The long-term efficacy of artificial sweeteners is still unclear, and impact every person differently.
Every person is genetically different and has different demands on their body. This means that the type and amount of carbohydrates each person should consume is completely different. There are a wide range of diets that change the amount and type of carbs a person should consume. I wouldn’t recommend changing anything in your diet after reading this. Instead, take a look at your diet and what you are consuming. What kind of carbs do you consume? How do they make you feel? Understanding how your current diet makes you feel is essential before you make any interventions.
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