NUTR 311 Nutrition for Health and Fitness

Fred W. Kolkhorst, Ph.D.ENS 311594-1924

fred.kolkhorst@sdsu.edu

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

Breakfast - McDonald's Energy(kcal)

Fat(g)

Sausage McMuffin w/Egg 517 331% Milk - 8 oz 110 2Hash Brown Potatoes 125 7

Lunch - Burger King Bacon Double Cheeseburger 510 31French Fries - regular 227 13Chocolate Shake - 10 oz 374 11

Snack Snicker's Candy Bar 280 13

Dinner - Taco Bell Two Tacos 372 16Combination Burrito 404 16Pepsi - 24 oz 288 0

TOTAL (40% of intake from fat) 3,207 142

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)

BMRest = 66.5 + 13.58*weight (kg) + 5*height (cm) – 6.8*age (years)

2. activity / exercise3. thermic effect of food (TEF)

~10% of energy intake (mixed diet)

Measuring & Estimating Energy Expenditure

Food + O2 CO2 + H2O + ATP + heat

• Direct calorimetry

• Indirect calorimetry

Energy Expenditure (kcal/min)

Activity 123 lb 183 lb basketball 7.3 11.5Circuit training 9.8 15.4Cycling (9.4 mph) 5.6 8.3Running (9 min/mile) 10.8 16.0Running (7 min/mile) 13.3 18.5Swimming (slow) 7.2 10.6Swimming (fast) 8.7 12.9Tennis (singles) 6.1 9.0Walking (3.0 mph) 4.5 6.6Sitting (quietly) 1.2 1.7

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) / height2 (m2)

> 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. Kolkhorst Dr. Buono

Kolkhorst Buono

Bioelectrical Impedance

Interpreting % fat (ages 18-30)

Rating Men Women

Excellent 6-10 10-15 Good 11-14 16-19 Acceptable 15-17 20-24 Too Fat 18-19 25-29 Obese >20 >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 0.9007 g/cm3

– FFM density is 1.1000 g/cm3

• SE = 2.5 - 3.0 %• 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 = 3.5 - 4.0%

• 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, 1994.

• http://www.gssiweb.com

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 – http://www.acsm-msse.org/pt/pt-core/template-journal

/msse/media/1201.pdf

• Nutrition and athletic performance – http://www.acsm-msse.org/pt/pt-core/template-journal

/msse/media/1200.pdf

Weight Management

• diet modification

• physical activity modification

• behavior modification

Principles Common to Successful Programs

Weight ManagementBehavior 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, 1997. [Roundtable Discussion] http://www.gssiweb.com