Practical Nutrition/Macronutrients/Carbohydrates

Introduction.

Complex vs Simple Carbs
Simple carbs are short chains of sugar molecules that are easy to digest and provide quick energy. Complex carbs are longer chains of sugar molecules that take longer to digest and provide more stable energy. Complex carbohydrates are digested slower and release glucose into the bloodstream at a more gradual rate. On the other hand, simple carbohydrates are digested rapidly and spike blood sugar faster and higher than complex carbs.

Practical Tips

 * Choose whole grains over refined grains. Whole grains contain more fiber and nutrients than refined grains. Examples of whole grains include brown rice, quinoa, oats, and whole-wheat bread and pasta.
 * Eat plenty of fruits and vegetables. Fruits and vegetables are low in calories and high in nutrients, including fiber, vitamins, and minerals.
 * Limit your intake of processed foods and sugary drinks. Processed foods and sugary drinks are high in simple carbohydrates and added sugars, which can contribute to weight gain and other health problems.

Comparison of Carbs and Fats
Carbohydrates and fats are both used in the body for energy, but they differ in the amount and speed of energy they supply, as well as the way they are stored and utilized. Here is a comparison of how they are used in the body:


 * Carbohydrates are the quickest source of energy, as they can be broken down and absorbed by the body quickly. They provide 4 calories per gram*. The body uses carbohydrates to fuel the brain and nervous system, as well as to maintain blood sugar levels. Excess carbohydrates are stored as glycogen in the liver and muscles, which can be quickly converted back to glucose when needed. However, the storage capacity of glycogen is limited, and any excess carbohydrates beyond that are converted to fat and stored in adipose tissue. Adipose tissue will be discussed later.
 * Fats are a slower source of energy (more apt for long-term storage than carbs), as they take longer to digest and absorb by the body. They provide 9 calories per gram*. The body uses fats for cell membrane structure, hormone production, and absorption of fat-soluble vitamins. Fats also serve as a backup source of energy when carbohydrates are not available. The body can store abundant amounts of fat in adipose tissue, which can be mobilized and oxidized when needed.
 * Carbohydrates and fats can be used for different types of physical activity, depending on the intensity and duration of the exercise. Carbohydrates are mainly used for high-intensity and short-duration activities, such as sprinting or weight lifting, as they can provide quick bursts of energy. Fats are mainly used for low-intensity and long-duration activities, such as walking or jogging, as they can provide sustained energy.

* See this section on macronutrients and calories for review if needed.

Fiber
Listen to this lecture on fiber: Lecture summary:


 * Fiber only comes from plants
 * You can't get fiber from meat, or any other animal sources.
 * Fiber is a carbohydrate, there is no fiber in fats whether animal or plant-based.
 * 97% of Americans don't get enough fiber.
 * The process of juicing a fruit removes fiber.
 * If fiber is contained in the skin of fruit (like apples), when you peel the skin off before eating it, you are removing a lot of its fiber.
 * Large apple with skin: 5.4g of fiber.
 * Large apple without skin: 2.8g of fiber.Apple peeling 4449.JPG
 * Benefits of fiber: satiety (feeling full), feeds good bacteria in our gut microbiome, helps eliminate waste (poop), reduces risk of obesity and type II diabetes.
 * Without gut bacteria, we can't digest fiber on our own.
 * The good bacteria in our gut digests and thrives on fiber. The good bacteria in our gut helps us maintain a healthy gut microbiome (see next bullet)
 * Side note: the gut microbiome plays a crucial role in preserving human health through nutrient provisioning, vitamin K synthesis, cellulose digestion facilitation, studies have also suggested it supports the promotion of angiogenesis (forming of new blood vessels from existing ones) and enteric nerve function.202004 Gut microbiota.svg
 * Fiber contributes 0 calories.
 * Fiber adds "bulk" to food.
 * Stretch receptors in the stomach send a message of fullness to the brain.
 * Our bodies absorb nutrients when they come in physical contact with our intestinal walls.
 * Fiber can help clean out the waste that lines intestinal walls.
 * Having excess waste on the intestinal walls can negatively affect nutrient absorption and cause other problems.