Exercise and Lipids

Types of Lipids

n Basic structure

n Same structural components as CHO except that there are more Carbon, Hydrogen, and Oxygen; hence more energy potential

n Specific types:

n Simple lipids – triglycerides

n Glycerol + 3 fatty acids

n Constitutes 90% of body’s fat particularly in adipose

n The Fatty Acids

n Saturated – contain single bonds between carbon atoms

n Unsaturated – contain 1 or more double bonds between main carbon atoms

n Monounsaturated – one double bond

n Polyunsaturated – 2 or more double bonds

Fatty Acids in Diet

n Average person consumes about 15% of total calories in form of saturated fats

n This creates health concerns due to potential for atherosclerosis (narrowing of blood vessels due to fatty deposits)

n Recommendation:

n No more than 10% of total diet should come from saturated fats

Compound Lipids

n Phospholipids and glucolipids – help make up cell structure

n Lipoproteins – transporters of fat in body

n Chylomicrons – metabolized by liver and delivered to adipose tissue

n HDL – good cholesterol; scavenges fat from blood vessel linings and transports to liver

n LDL – bad cholesterol; delivers cholesterol to arterial walls (development of smooth muscle)

n VLDL – very bad cholesterol; transport triglycerides to muscles and adipose tissue

Simple View of Lipoprotein

HDL-C LDL-C

Derived Lipids

n Cholesterol –

n Exists only in animal tissue

n Functions:

n Structural component of plasma membranes of cells

n Precursor to formation of Vitamin D, adrenal and sex hormones

n Component of bile (helps digest fats)

n Assists in fetal development

Lipid’s Role in Body

n Energy Reserve

n At rest, provides 80-90% of body’s energy needs

n Averages:

n 15% in men; 25% in women

n Enough energy to run from NYC to Madison, WI

n Protection and Insulation

n 4% of body fat is considered protective against trauma; subcutaneous fat is for insulation (50% of body’s fat amount)

n Vitamin Carrier

n Carries fat-soluble vitamins A, D, E, K

n Contributes to Satiety

n Don’t feel as hungry to eat more

Recommended Lipid Intake

n Should not exceed 30% of total diet

n Unsaturated fatty acid should supply at least 70% of total lipid intake

n No more than 300 mg of dietary cholesterol per day (yolk of one large egg) – Am Heart Assoc.

Fat Use in Exercise

n In initial hour of exercise, fat contributes approximately 50% of energy needs

n After 3 hours of exercise, fat contributes up to 70% of energy needs