Chapter 17 – Nutrition
Know all Definitions throughout the chapter
Nutrition: the process of providing or obtaining the food necessary for health and growth.
calorie: the energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.1868 joules).
Calorie: the energy needed to raise the temperature of 1 liter of water 1 °C.
Kilocalorie: One thousand of the above definition.
Protein: large biomolecules, or macronutrient, consisting of one or more long chains of amino acids.
Carbohydrates: sugars, starch, and cellulose that contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body.
Lipids: any of a class of organic compounds that are fatty acids or their derivatives and are insoluble in water but soluble in organic solvents. They include many natural oils, waxes, and steroids.
Compare definitions to Chapter 17 in the textbook.
Compare to Table 17.4 Know all of the Essential Amino Acids
Essential amino acids: Luecine, Isoleucine, Valine (BCAA’s)
Lysine, Methionine, Tryptophan, Threonine, Phenylalanine
Compare to Table 17.6 Recommended Protein Intake
Inactive adults need about .8 grams per kilogram bodyweight
Athletes need more protein: Endurance athletes 1.2-1.4 g/kg and Strength Athletes need 1.2-1.7 g/kg
Daily recommendations for fiber
Adults need about 38g of fiber per day. The minimum recommended is 25g per day.
Specific recommendations for endurance athletes
Endurance Athletes need more carbohydrates to fuel their activities. This is because they need to build the storage of glycogen in their muscles and liver which will not only enhance recovery but drive their performance upward. Carbohydrates are recommended at 6-10 g/kg per day.
Know the difference between the three types of fatty acids.
Monounsaturated Fatty Acid: Increase good cholesterol (HDL) and have one double bond in their carbon chain – Mono meaning 1.
Polyunsaturated Fatty Acid: Increase good cholesterol and are composed of essential fatty acids which cannot be made by the body. More than one double bond in their carbon chain – Poly meaning more than 1.
Saturated Fatty Acid: Saturated fats increase bad cholesterol (LDL) levels and have no double bonds in their carbon chain – which is why they are called saturated.
Lipids in the body
What are the functions of lipids in the body?
Lipids have several roles in the body, these include acting as chemical messengers, storage and provision of energy and so forth.
All multicellular organisms use chemical messengers to send information between organelles and to other cells. Since lipids are small molecules insoluble in water, they are excellent candidates for signalling. The signalling molecules further attach to the receptors on the cell surface and bring about a change that leads to an action. The signalling lipids, in their esterified form can infiltrate membranes and are transported to carry signals to other cells. These may bind to certain xenical weight loss pills proteins as well and are inactive until they reach the site of action and encounter the appropriate receptor.
Storage and provision of energy
Storage lipids are triacylglycerols. These are inert and made up of three fatty acids and a glycerol. Fatty acids in non esterified form, i.e. as free (unesterified) fatty acids are released from triacylglycerols during fasting to provide a source of energy and to form the structural components for cells. Dietary fatty acids of short and medium chain size are not esterified but are oxidized rapidly in tissues as a source of ‘fuel”. Longer chain fatty acids are esterified first to triacylglycerols or structural lipids.
Maintenance of temperature
Layers of subcutaneous fat under the skin also help in insulation and protection from cold. Maintenance of body temperature is mainly done by brown fat as opposed to white fat. Babies have a higher concentration of brown fat.
Membrane Lipid Layer Formation
Linoleic and linolenic acids are essential fatty acids. These form arachidonic, eicosapentaenoic and docosahexaenoic acids. These for membrane lipids. Membrane lipids are made of polyunsaturated fatty acids. Polyunsaturated fatty acids are important as constituents of the phospholipids, where they appear to confer several important properties to the membranes. One of the most important properties are fluidity and flexibility of the membrane.
Much of the cholesterol is located in cell membranes. It also occurs in blood in free form as plasma lipoproteins. Lipoproteins are complex aggregates of lipids and proteins that make travel of lipids in a watery or aqueous solution possible and enable their transport throughout the body.
Daily recommendations and importance of water
Drink 3.0 liters of water if you are male or 2.2 liters of water if you are female. Drink more water if you are trying to lose weight. Water is important as it improves body functions including liver, endocrine, and metabolic. It maintains blood volume and regulates body temperature.
Compare to Table 17.11 The effects of dehydration
|Mild to Moderate Dehydration||Severe Dehydration|
|Dry, sticky mouth||Extreme thirst|
|Sleepiness or tiredness||Irritability and confusion|
|Dry skin||Sunken eyes|
|Headache||Dry skin that doesn’t bounce back when you pinch it|
|Decreased sweat rate||Low blood pressure|
|Dizziness or lightheadedness||Rapid heartbeat|
|Few or no tears when crying||Rapid breathing|
|Water retention||No tears when crying|
|Decreased blood pressure||Increased body temperature|
|Muscle cramps||Little or no urination, and any urine color that is darker than usual|
|Sodium retention||In serious cases, delirium or unconsciousness|
Be familiar with guidelines for altering body composition
These guidelines stick to your general “law of thermodynamics” recommendations.
Lose weight: Eat less, exercise more, choose whole grains and avoid processed foods. Drink lots of water and avoid alcohol.
Gain weight: Eat more frequently, intake more than you expend, eat lots of carbs and fat.
Calorie count for proteins, carbohydrates, fats
PRO = 4kcal/gram
CHO = 4kcal/gram
FAT = 9kcal/gram
Alcohol = 7