Lecture 9: Weight Management Flashcards
Energy Out: Basal Metabolic Rate
- Energy required to maintain functions of the body while at rest (after 12 hr fast & rest)
- Involuntary activities: respiration, circulation, synthesize new cells & hormones, sending nerve signals, fluid balance, body temperature
- BMR accounts for about 60-70% of TEE
Energy Out: Basal Metabolic Rate (Determinants)
- Lean Body Mass (age, gender)
- Obese usually have higher LBM and burn more Calories/d
- Height (LBM and body surface)
- Age: decrease BMR 3-5%/10 yrs after age 30 (LBW and hormone changese
- thyroid hormone: (incease BMR)
- starving/fasting: (decrease BMR)
- Growth: want your BMR to increase
- Healing/fever (7% increase BMR)
Can you change your BMR?
- Increase: building or maintain LBM – physical activity, >1.05g/kg protein intake* (research still conducted)
- Decrease: energy restricted diets, lower lean body mass
Energy Out: Physical Activity/Exercise
-Most variable of outputs
-Accounts for ~15-35% of TEE
*Couch potato: ~ 10%
*Athlete in training ~ 50%
Dual effect on output
↑ Energy expenditure during and after exercise
↑ LBM= ↑ BMR
- Energy costs of various activities (table 13.2)
- Higher intensity= more Calories burned per minute
- Stretching vs running at 8.6 mph
Energy Out: Thermic Effect of Food
- Energy used in food digestion, absorption, transport metabolize, and storage of nutrients
- TEF accounts for ~5-10% of the energy consumed & TEE
- Consume 500 Kcals = 25-50 Kcals needed for TEF
- Perhaps more energy needed metabolize protein and carbohydrate than fat
- Meta-analysis found higher protein (25-35% Calories), low-fat diet had more weight loss (~2lbs) than lower protein (12-18%), low-fat diet with similar Caloric intake*
- AMDR for protein: 10-35%
Alternative Means to “Speed Up Your Metabolism”
- Protein
- may preserve LBM: > 1.05 g/kg/d
- Increase thermogenesis
- Satiety
- Caffeine
- Increase BMR but has not shown to reduce body weight
- Increase blood pressure, irregular heartbeat, sleep disturbance
- Capsaicin in chili peppers (cayenne pepper)
- Cold water: REE increases 25-30% for 30-40 min
Fed & Overfed State
- Glucose for energy, maintain blood glucose levels, then glycogen formation
- Remaining glucose converted to FA for energy storage
- Amino acids used for body protein needs
* Excess converted to FA for energy storage - FA used for fuel
* Excess stored excess body weight
Short-Term Fast (0-6 hrs)
- 0-6 hr fast (between meals & overnight)
- Liver glycogen to maintain blood glucose levels and for energy
- Gluconeogenesis to maintain blood glucose levels and glucose for brain
- FA for energy
3-5 Day Fast
- 3-5 d fast (no glycogen left)
- Gluconeogenesis- fast rate of protein breakdown (and glycerol) for maintaining blood glucose levels
- FA & Ketones
5-7 Day Fast
-5-7 d fast
*Metabolic rate slows and energy needs declines
*Gluconeogenesis slows down
1. Ketones & FA- nervous system adapts to use ketones, spares protein.
2 . Gluconeogensis from protein (to keep the TCA cycle working & maintain BG levels & for RBC)
Estimating Energy Requirements
Techniques
Macronutrients + O2 –> ATP + CO2+ H2O and heat
- Direct calorimetry
- Indirect calorimetry
- Record intake over 3-7 days and use average
- Rough estimate
- Predictive equations
DRI: Estimated Energy Requirement (EER)
- Average dietary energy intake (kcal) to maintain energy balance in a healthy adult
- Individualized: age, gender, weight, height, level of physical activity
- Modified if healing, disease or pregnancy
A Healthy Body Weight
-Body weight: bone, muscle, fat, tissue, fluid*, blood etc.
-What is a healthy body weight?
*A weight appropriate for your age, physical development
*A weight that someone can realistically achieve without disordered eating & exercise patterns & is acceptable to the individual
*A weight where your nutrient needs can be met
*A weight associated with reduced disease risk
~Overweight & obesity are associated with DM, HTN, heart disease, stroke, gallbladder dz., osteoarthritis, sleep apnea, cancers (endometrium, breast, prostate, colon)
*Adequate lean and fat tissues
Estimation of Healthy Weight
For men:
106 pounds for the first 5 feet
add 6 pounds per each inch over five feet
A man who is 5’10” should weigh 166 lbs. (149-183 lbs)*
For women:
100 pounds for the first 5 feet
add 5 pounds per each inch over five feet
A women who is 5’10” should weigh 150 lbs. (135-165 lbs)*
*+/- 10% for frame size
110-120%: overweight
>130%: obese
Assessing Body Weight: Body Mass Index
Body mass index (BMI)= weight (kg)/height (m)2
BMI = [weight (lbs) / height (inches)2] x 703
Underweight: <18.5 Normal: 18.5-24.9 Overweight: 25-29.9 Obese: 30 or greater Morbid Obesity: 40 or greater
Assessing Body Weight: Body Mass Index (disease and limitation)
Disease risk increases when BMI 25, especially >30
Limitations:
- Fat distribution
- Doesn’t take muscle mass and bone size into account
- Not as useful in people >65
- Ethnic variation (higher risk of disease at lower -BMI and waist circumferene cut-offs)
Body Composition: Assessing LBM vs Fat Mass
Methods are estimates:
- Fat folds (skin folds)
- Underwater weighing
- Bioelectrical impedance
- Dual-energy x-ray absorptiometry (DEXA)
- Bod Pod
Body Fat Distribution
Abdominal fat increase chronic disease risk
- Waist-to-hip ratio
- Men > 0.90
- Women > 0.80
- Waist circumference
- Men above 40 in. (or 102 cm.)
- Woman above 35 in. (or 88 cm.)
Concerns of Being Overweight/Obese
Overweight & obesity are associated with:
- Hypertension
- Metabolic Syndrome
- Type 2 Diabetes Mellitus*
- Heart disease & stroke*
- Cancers* (endometrium, breast, prostate, colon)
- Gallbladder dz.
- Osteoarthritis
- Sleep apnea
- In the top 10 leading causes of death
Metabolic Syndrome
Must have 3 of these 5 criteria:
- Waist circumference
- Male > 40 in.
- Female > 35 in.
- TG > 150 mg/dL
- HDL-C: male < 40 and female < 50 mg/dL
- Blood Pressure > 130/85 mmHg
- Fasting Blood Glucose > 100 mg/dL
Fitness vs Fatness
- Overweight with the absence of risk factors
- Health at Every Size
- Self-acceptance: human beauty regardless of weight
- Physical activity: enjoyment & quality of life
- Normalized eating: peaceful relationship with food, relearn to eat in response to hunger and fullness cues.
- Remaining concerns: osteoarthritis, cancers, gallstones, erectile dysfunction, sleep apnea
Why Are So Many People Overweight?
- Last 2 decades
- Overweight children doubled
- Overweight adolescents tripled
- Calories in vs out but is this harder than it seems?
- Genetics (Nature)
- Environment (Nurture)
- 69.2% of Adult Americans are overweight or obese
- 36% are obese
- 18% children 6-19 are obese
Hormone: Leptin
release site: Fat (obese produce more but are not sensitive to signaling)
-decreases feeding
Hormone: Insulin
Release site: Pancreas
- decreases feeding
