Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Chapter 1 Carbohydrates, Lipids, and Proteins

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Carbohydrates The nature of carbohydrates –Composed of: Carbon Hydrogen Oxygen –General formula (CH 2 O) n –Alterations in atomic arrangement makes molecules distinctly different

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Types of Carbohydrates Monosaccharides –Basic unit of carbohydrates Oligosaccharides –2 to 10 sugars bonded chemically Disaccharides – very common Polysaccharides –3 to thousands of sugars linked together

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Monosaccharides Glucose Fructose Galactose

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Oligosaccharides Lactose = Glucose + Galactose Sucrose = Glucose + Fructose Maltose = Glucose + Glucose

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Polysaccharides Plant polysaccharides –Starch Amylose Amylopectin –Fiber Water-soluble Water-insoluble

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Recommended Intake of Fiber 20 – 40 g fiber per day (depending on age) Ratio of 3:1 for water-insoluble to water- soluble fiber

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Recommended Intake of Carbohydrates 40 – 50% of total calories Increase to 60% if physically active During training, athletes may increase up to 70%

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Carbohydrates Role of carbohydrates in the body –Energy source –Catabolism of blood glucose and glycogen from the liver and muscles fuels muscle contraction –The higher the intensity of the exercise, the greater the reliance on carbohydrate as a fuel

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Carbohydrates Role of carbohydrates in the body –Protein sparer When carbohydrates become depleted, proteins are increasingly converted to glucose in a process called gluconeogenesis.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Carbohydrates Role of carbohydrates in the body –Metabolic primer Glycogen depletion causes fat mobilization to exceed its oxidation, resulting in increased ketone formation. This may lead to ketosis.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Role of carbohydrates in the body –Fuel for the central nervous system The brain relies almost exclusively on glucose. Hypoglycemia: depletion of glycogen causes weakness, hunger, and dizziness. Carbohydrates

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Carbohydrate Dynamics in Exercise During intense exercise –Glycogenolysis is stimulated by Increase in epinephrine Increase in norepinephrine Increase in glucagon Decrease in insulin

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Carbohydrate Dynamics in Exercise Moderate and prolonged exercise –Fuel mix depends on exercise intensity. –The more intense the exercise, the greater the reliance on carbohydrates. –During light exercise, a greater percentage of the fuel comes from fat. –In the later stages of prolonged exercise, fat and protein use increases as carbohydrates become depleted.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Lipids The nature of lipids Lipids have the same structural components as carbohydrates. Lipid is a general term that includes –Oils –Fats –Waxes

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Kinds of Lipids Simple lipids Compound lipids Derived lipids

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Simple Lipids Triacylglycerols are the most common –Composed of 3 fatty acids and a glycerol

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Types of Fatty Acids Saturated fatty acids contain only single covalent bonds between carbon atoms. Unsaturated fatty acids contain one or more double bonds along their main carbon chain.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Simple Lipids Lipids are primarily stored as triacylglycerol in adipocytes.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Triacylglycerol Formation

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Triacylglycerol Breakdown

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Lipids in the Diet

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Compound Lipids Triacylglycerol components combined with other chemicals –Phospholipids –Glycolipids –Lipoproteins

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Lipoproteins Chylomicrons – exogenous transport from intestines to the liver HDL – reverse cholesterol transport VLDL – transport triacylglycerols to cells LDL – delivers cholesterol to arterial tissue

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Derived Lipids Cholesterol –Classified as lipid –Exogenous and endogenous –Builds plasma membranes –Synthesizes vitamins, hormones, bile –High levels are a predictor of coronary artery disease

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Recommended Dietary Lipid Lipid intake should be < 30% of total kCals –Replace high-fat foods with fruits, vegetables, grains, low-fat dairy products, and lean meats –Cholesterol intake ~ 300 mg/day

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Lipids Role of lipid in the body –Energy source and reserve –Protection of vital organs –Thermal insulation –Vitamin carrier –Hunger depressor

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Fat Dynamics in Exercise Intracellular and extracellular fats supply 30 – 80% of the energy for physical exercise. Exercise intensity governs fat’s contribution to metabolic mixture.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Proteins Proteins contain –Carbon –Hydrogen –Oxygen –Nitrogen Proteins are made up of amino acids –Amine group –Organic acid group –R group or side chain

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Kinds of Protein Essential amino acids – cannot be synthesized in the body Nonessential – the body is able to synthesize Complete proteins contain all the essential amino acids. Incomplete proteins lack one or more of the essential amino acids.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Protein Sources Sources of complete protein –Eggs –Milk –Meat –Fish –Poultry Biologic value is based upon how well a food supplies essential amino acids.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition The Vegetarian Approach To get all of the essential amino acids, combine grains, legumes, and vegetables.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Recommended Dietary Protein Intake The RDA: A liberal standard –0.83 g/kg body mass for adults –2.0 – 4.0 g/kg for infants and growing children –10% increase for vegetarians –Some modification may be required for athletes.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Role of Protein Three major sources of body protein –Blood plasma –Visceral tissue –Muscle Amino acids are major building blocks for synthesizing tissue.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Dynamics of Protein Metabolism Amino acids not used structurally undergo deamination. The nitrogen is removed to form urea. The remnant may be –Converted to a different amino acid –Converted to carbohydrate or fat –Catabolized for energy

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Nitrogen Balance Occurs when intake equals excretion Positive – indicates new tissue being synthesized Negative – indicates protein use for energy; possible encroachment on amino acids

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Protein Dynamics in Exercise Protein is oxidized more extensively as carbohydrates become depleted. It is important for athletes to consume adequate carbohydrate to conserve lean tissue.

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition The Alanine-Glucose Cycle