NUTR 311 Nutrition for Health and Fitness Fred W. Kolkhorst, Ph.D. ENS office hours: MWF 9-11 and by appointment-

Energy Balance Energy balance = energy intake – energy expenditure Energy intake caloric density –CHO = 4 kcal  g -1 –protein = 4 kcal  g -1 –fat = 9 kcal  g -1 –ethanol = 7 kcal  g -1 influence of diet composition

Calculate % Intake from Fat

Energy Intake: Satiety Hunger (internally influenced) appetite (externally influenced) affect satiety Satiety (no further desire to eat) is influenced by: –hypothalamus – primary regulator –energy density of foods, glycemic load, visual cues –body composition (i.e. production of leptin) –hormonal influence

Energy Expenditure 1.basal metabolic rate (BMR) affected by: –energy intake –exercise –Predicting BMR (Harris-Benedict Equation) BMR est = *weight (kg) + 5*height (cm) – 6.8*age (years) 2.activity / exercise 3.thermic effect of food (TEF) ~10% of energy intake (mixed diet)

Measuring & Estimating Energy Expenditure Food + O 2  CO 2 + H 2 O + ATP + heat Direct calorimetry Indirect calorimetry

Energy Expenditure (kcal/min)

Effects of low- energy intake on RMR

Effects of low- energy intake and exercise on RMR

Determining Ideal Body Weight Metropolitan height–weight tables body mass index (BMI) weight (kg) / height 2 (m 2 ) > 25.0 considered to be overweight hydrostatic (underwater) weighing anthropometric (skin-fold) measurements bioelectrical impedance analysis (BIA)

Body Composition most methods consider body having two components: –fat component, i.e. fat mass –fat-free component, i.e. fat-free mass (FFM) essential and non-essential fat body fat % is the % of total body weight –average values: women, ~25%; men ~15% –minimal values: women, 8-12%; men – 5% –considered obese: women, >30%; men >20%

Dr. KolkhorstDr. Buono Kolkhorst Buono

Bioelectrical Impedance

Interpreting % fat (ages 18-30)

Hydrostatic (Underwater) Weighing determines body density principles involved: –fat is less dense than water –FFM is more dense than water assumptions: –fat density is g/cm 3 –FFM density is g/cm 3 SE = % accuracy influenced by sex, age, race, muscle mass, RV determination

Anthropometric (Skinfold) Measurements >100 equations available from which to choose most commonly used –and most accurate–are generalized equations by Jackson et al. SE = % accuracy affected by extremes in age, % fat, race

Suggested Reading on Body Composition Houtkooper, L.B. and S. Going. Body Composition: How should it be measured? Does it affect sport performance? 7(5), SSE#52,

Body Composition and Sport Performance clear relationship between low % fat and better performance Question: What is ideal % fat? potential consequences of large weight loss: –chronic fatigue –Female Athlete Triad

ACSM Position Stand Weight loss strategies – journal/msse/media/1201.pdfhttp:// journal/msse/media/1201.pdf Nutrition and athletic performance – journal/msse/media/1200.pdfhttp:// journal/msse/media/1200.pdf

Weight Management diet modification physical activity modification behavior modification Principles Common to Successful Programs

Weight Management Behavior Modification avoid automatic eating plan meals ahead of time don’t serve self more food than should eat avoid social binges practice other stress management techniques set realistic goals incorporate physical activity into program

Weight Management Summary lose weight slowly (i.e.  2 lb/week)  energy intake  fat intake  complex CHO and fiber intake exercise regularly (3-5 X/week) modify eating habits/attitudes

Female Athlete Triad female athletes most prone to eating disorders, affects 30-65% insufficient energy intake causes menstrual dysfunction infrequent or absence of menstruation will  mineral absorption by bone  bone mineral density will  risk of bone injury and may have life-long effects

Suggested Reading on Female Athlete Triad The Female-Athlete Triad. 8(1), RT# 27, [Roundtable Discussion]