Frequently Asked Questions about Nutrition, Hydration and Exercise Nutrition
Q. What is the glycemic index?
A. The Glycemic Index (GI) is a measure of how quickly the carbohydrates (sugar) are absorbed into the blood stream. Carbohydrates that breakdown quickly during digestion have the highest glycemic indexes. The blood glucose response in these foods is fast and high, often causing what is commonly called "sugar rushes." Carbohydrates that break down slowly, releasing glucose gradually into the blood stream, have low glycemic indexes. These foods give you sustained energy over a longer period of time.
Q. What is the big deal about foods with a low glycemic index?
A. Foods with a low glycemic index can:
Help people lose weight
Improve the bodys sensitivity to insulin
Help control diabetes
Keep the body feeling fuller for a longer time
Increase physical endurance
Q. What are some foods and their cooresponding glycemic index?
Instant rice - 124
Jellybeans - 114
French fries - 107
Soda crackers - 106
White bread - 100
Ice Cream - 93
Baked Potato - 85
Corn Flakes - 84
Table Sugar - 83
Graham Crackers - 74
Popcorn - 58
Brown Rice - 55
Sweet Potato - 54
NuGo BARS - 45-48 Flavors vary
Apple Juice - 41
Apple - 36
Mixed Grain Bread - 35
Green Beans - 30
Lentils 29
Whole Milk - 27
Soybeans - 18
Q. With all this talk about fats, do we need fat in our food?
A. Nutritionists and food experts have been going round and round on the issue of fat, leaving you, the consumer, almost in the dark. A healthy body does needs some amount of fat. Fat is required to maintain cardiovascular health, provide extended endurance, maintain healthy skin, and improve hormone balance. Understanding which fats and how much to consume can cause confusion. Below are some questions and answers about several types of fats.
Q. What are monounsaturated fats?
A. Monounsaturated fat is currently considered to be a healthier type of fat. It tends to lower blood cholesterol and may assist in reducing heart disease. Both monounsaturated and polyunsaturated fats provides essential fatty acids for health skin and development of body cells. Olive oil, almonds, cashews, hazelnuts and avocados are some examples of foods containing monounsaturated fats.
Q. What are polyunsaturated fats?
A. These fats are usually in a liquid form at room temperature. Polyunsaturated fats are found in fish, fish oils and vegetables oils such as soybean oil, corn oil, and sunflower oil. Polyunsaturated fats have more health benefits than saturated, hydrogenated or trans fats. These fats have been shown to lower LDL cholesterol levels and total blood cholesterol.
Q. What are saturated fats?
A. This fat is usually solid or almost solid at room temperature. Animal fats, poultry and dairy products are saturated. Some vegetable oils can be saturated. Saturated fat is the one of the most important factors for determining blood cholesterol levels. Studies have shown that consuming products high in saturated fat can raise LDL (bad) cholesterol. High levels of LDL are linked to heart disease, arteriosclerosis, cancer and diabetes
Q. What are hydrogenated fats?
A. In the hydrogenation process, hydrogen is added to unsaturated fat to give it more density. This process turns liquid oil into a solid fat or solid vegetable shortening. This process, however, takes away the healthy benefits of the unsaturated fat.
Q. What are trans fatty acids?
A. These fats are a by-product of the hydrogenation process where hydrogen is added to make the fat more saturated. Trans fats are created when oils are partially hydrogenated. Although this process increases a products shelf life, trans fats can elevate blood cholesterol levels and increase the risk of heart disease.
Q. What is cholesterol and how does it get into my body?
A. Cholesterol is part of every healthy body. It's a waxy like substance found in the bloodstream and is necessary for good cell production. Some of your cholesterol is made in the body and the rest comes from the cholesterol found in foods you eat, i.e. meat, fish, eggs, butter and cheese.
Cholesterol is carried to and from the cells by carriers called lipoproteins. Basically there are two kinds: low-density lipoproteins (LDL or bad cholesterol) where too much of the LDL can clog your arteries; and high-density lipoproteins (HDL or good cholesterol) is carried away from your heart. Studies indicate that high levels of HDL reduce your risk of heart attack.
Q. Can consuming protein with carbohydrate during exercise increase endurance?
A. Yes, definately.It appears that the effectiveness of carbohydrate consumption during exercise is limited by the maximum rate at which the liver can release glucose into the bloodstream about 1 gram per minute. Its not hard to consume enough carbohydrate in a sports drink to reach this limit, and consuming any more will not help.
But the muscles can also use protein for energy. A study at the University of Texas compared the effects of a carbohydrate and a carbohydrate-protein supplement on endurance performance. Trained cyclists exercised at variable exercise intensities for three hours, then they cycled 85% at VO2max until exhausted. Two hundred ml of each of three supplements (water, carbohydrate, carbohydrate-protein) was provided every 20 minutes. The carbohydrate-protein drink increased time to exhaustion by 36% over the carbohydrate supplement and by 55% more than water.
Q. Can consuming protein during exercise help reduce muscle damange?
A. Yes, definately. When protein is not consumed during exercise, muscle proteins are broken down for energy, resulting in muscle damage. When protein is consumed during exercise, such damage is minimized.
This was demonstrated in a study at James Madison University. Researchers fed either a regular carbohydrate sports drink or a carbohydrate-protein drink to subjects during a hard stationary bike ride and measured post-exercise levels of creatine phosphokinase (CPK) in the blood. CPK is a biomarker of muscle damage. The subjects receiving the carbohydrate/protein supplement had CPK levels 83% lower than those receiving the carbohydrate supplement, indicating significantly less muscle damage during exercise.
Q. What is the big deal about post-exercise nutrition and will it help my performance for the next workout?
A. It stands to reason that if immediate supplementation after exercise results in a faster, stronger recovery, it could also improve performance in the next workout. The James Madison University study cited above showed this to be the case.
After completing a performance ride on day one, the subjects of this study were asked to come back after a 15-hour recovery period. Upon returning, the subjects performed a ride to exhaustion at 85% of their VO2max. Subjects receiving the carbohydrate/protein drink during the initial performance ride the day before were able to ride almost 40% longer than those receiving the carbohydrate drink during the prior exercise.
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