Peak Nutrition. Maria Hines
transport chain (a system of rapidly moving electrons that creates kinetic energy to generate ATP). It’s important to note that the two key enzymes that start the Krebs cycle are pyruvate (from glycolysis and amino acids) and acetyl-CoA (from fatty acids). Some supplements that assist in this more aerobic environment are sodium phosphate, cordyceps mushrooms, beet juice, and green tea extract (see chapter 12, Supplements for Mountain Athletes).
During exercise, all of these energy systems are at work, but one or more are amplified depending on the intensity of your workout and the availability of oxygen (see table 6.1 for more on this). For these processes to work efficiently, especially for mountain athletes, nutrition has to be optimal—not just the food, but also the vitamins and minerals. They play a massive part in the chemical steps that lead to regenerating ATP. If you don’t get sufficient nutrition, these processes can be altered, ultimately compromising your athletic performance and even your health.
One example of how essential vitamins play a big part in chemical reactions during oxidative phosphorylation involves vitamins B2 and B3. Molecules that attract hydrogen ions such as NAD+ are actually derived from these vitamins. A lack of these vitamins, or any other mineral or vitamin, can significantly affect energy levels and body composition, and can make whatever mountain sport you’re into more difficult. That is why it’s so important to be intentional about what you eat and potentially supplement if you are aware of deficiencies.
MITOCHONDRIA AND TRAINING FOR ENDURANCE
The more you train for endurance and power endurance, the more mitochondria and blood vessels you develop in your muscle tissue. You already have a load of mitochondria in your brain and your heart, because those muscles are always working. The target for your training will vary depending on sport-specific functions. For example, climbers use aerobic, restoration, and capillarity training (ARC) to develop mitochondria and capillaries in the forearms, so that the muscles can continue to perform contractions as they climb. The same goes for running—runners often do long, slow distance workouts that build lung capacity as well as mitochondria and capillary density in the legs and other working muscles. A nicely targeted training program can help with this development. For a variety of training tools and programs for a host of outdoor sports, visit modusathletica.com.
MACRONUTRIENTS: CARBS, FAT, AND PROTEIN
During training—or any period of activity and exertion for an athlete—macronutrients are what fuel the energy systems. Let’s take a closer look at some of the functions and best practices for optimally supporting each system.
Mitochondria have many roles in the body. A mitochondrion is an organelle that is the powerhouse of a cell. It acts like a digestive system, breaking down nutrients and producing a ton of energy in the form of ATP. Mitochondria are found in all cells. Muscles have a lot of them because of the energy demand during exercise. Endurance athletes have and need more of these than power athletes.
Carbohydrates
There are three groups of carbohydrates: monosaccharides, oligosaccharides, and polysaccharides. Monosaccharides are the simplest form of carbohydrates; these include glucose, fructose, and galactose (fruits and starchy carbs have these simple sugars in them). Oligosaccharides are chains of two or three monosaccharides, such as sucrose (sugar), maltose, and lactose (sweet potatoes and cheese are examples of foods containing oligosaccharides). Polysaccharides are long chains of monosaccharides, such as starch, glycogen, and fiber (whole-grain bread and legumes contain these). All sugars are eventually broken down to glucose in the bloodstream. In the stomach, carbs are the first to be passed through, which is why you may not feel full if you eat a high-carbohydrate meal. Around 20 grams of glucose circulates in the bloodstream every hour. If your blood sugar drops, either the liver will dump glucose into the bloodstream or you will have to eat something to supply new glucose. Only glycogen in the liver can provide glucose. Muscle cell glycogen is reserved for glycolysis in that muscle cell. If there is excess glucose in the blood, the liver and muscle cells will take up what they can, and then the rest gets stored as fat.
Carbohydrates and Energy Transfer
The body can store only a limited supply of carbohydrates. If you went without eating, your carbohydrates would be depleted within a day, whereas fats would last you a few days, maybe more. As a result, you need to ingest carbs frequently, but you don’t need a diet high in them to get the energy you need. Glucose can also be broken down from muscle, and you’ll learn later in this chapter how fat can provide you with plenty of energy (known as fat adaptation). Carbs can be used in five different metabolic pathways to provide ATP for movement:
•Glycogenesis: glucose to stored glycogen
•Glycogenolysis: glycogen to glucose
•Glycolysis: glucose to pyruvate
•Krebs cycle and electron transport chain: acetyl-CoA to ATP, CO2, and H2O
•Gluconeogenesis: noncarbohydrates to glucose
GLYCEMIC INDEX
The glycemic index of a food is a measure of how quickly the food increases blood glucose. Table sugar gets a score of 100, and all other foods are calculated relative to this score. Glycemic index can be a useful guide for understanding which foods cause blood glucose spikes; however, it is all relative, and it depends on the serving size of the food and the food combinations. In general, to have a healthy body composition and optimal athletic performance, eat as many foods with a lower glycemic index as possible, such as legumes, vegetables, fruits, and whole grains.
High-glycemic foods—such as sugar, breakfast cereals, and white bread—spike blood glucose and as a consequence also spike insulin levels. Low-glycemic foods—such as legumes, most fruits, and nonstarchy vegetables—tend to be digested at a much slower rate. This is excellent for performance—you feel more satiated, micronutrients are absorbed better, more fiber is ingested, blood sugar and insulin levels are better controlled, your muscles can repair faster, energy levels stay consistent during activity, and your performance improves. A diet abundant in high-glycemic, fast-acting carbs can make you feel sluggish and hungry, with inconsistent energy levels, leaving you to bonk or rapidly drop in blood glucose levels during activity. The best time to eat these types of carbs is during or right after exercise when insulin is the most sensitive and when muscles are hungry for more glucose.
Slow-digesting carbs have dietary fiber, which is very important for gut health, cholesterol levels, and healthy bowel movements. You want to get a minimum of 25 grams of fiber each day from both soluble and insoluble fiber (found in beans, legumes, dark leafy greens, and green beans). Higher fiber intake is preferable and has been shown to reduce the risk of colon cancer, heart disease, diabetes, and insulin resistance.
Dietary carbohydrates are all broken down to glucose in the blood. The body then takes it up and stores it as glycogen (glycogenesis). When you start to work out, and your body needs energy, it breaks down glycogen to form glucose (glycogenolysis) and then further breaks the glucose down into pyruvate (glycolysis) if the activity is intense enough to provide your cells with ATP. If the exercise is reasonably moderate and long duration, pyruvate is converted into acetyl-CoA (and joined to oxaloacetate, a by-product of carbohydrate metabolism) and shuttled into the