1. PROTEINS
PROTEIN

2. How Does the Body Use Protein?
Found in 40% of skeletal muscle, 25% in organs and the remainder in the skin and blood

3. Structure of Protein

4. Structural Differences Between Carbohydrates, Lipids, and Proteins
Figure 6.1

5. Best Sources of Protein
Figure 6.14

6. Essential, Nonessential, and Conditional
Conditionally essential – cannot be synthesized due to illness or lack of necessary precursors
Premature infants lack sufficient enzymes needed to create arginine

8. Protein Quality Complete proteins Incomplete proteins
Contain all nine essential amino acids
Usually animal source are complete proteins
Are considered higher quality
Incomplete proteins
Low in one or more essential amino acid
Usually plant sources are incomplete

9. Protein Digestion
Figure 6.6

10. Metabolic Fate of Amino Acids
Figure 6.7

11. How Much Protein Do You Need?
Healthy, nonpregnant adults
Should consume enough to replace what is used every day
The goal is nitrogen balance
Pregnant woman, people recovering from surgery or injury, and growing children
Should consume enough to build new tissue

12. Nitrogen Balance and Imbalance
Figure 6.12

13. Eating Too Much Protein

14. Protein Deficiency

15. Dietary Recommendations
healthy individuals: 0.8 g/kg/day
Endurance athletes: 1.2 to1.4g/kg/day
9-10% daily energy
Resistance athletes: 1.6 to 1.7g/kg/day
14-15% daily energy
Extra protein is needed to repair damaged muscle fibers, decrease the rate of muscle protein breakdown, and synthesis of new protein molecules

16. Protein Bars Are marketed as convenient and portable Can be
A peanut butter sandwich is portable and lower in saturated fat and sugar and higher in fiber than some protein bars

17. Whey is derived from
cow’s milk. As the
schematic on the right
shows, whole milk is 13%
“stuff”.
That stuff is ~27% protein
The protein is ~20% whey

18. What is whey anyway? contains little to no fat, lactose or cholesterol
high proportion of branched chain amino acids (BCAA)
BCAA – amino acids (leucine, isoleucine, valine) are not
synthesized and therefore must come from the diet
Leucine is an initiator of protein synthesis
rapidly absorbed
Whey protein is a dairy protein and recent research suggests that calcium and other minerals in dairy may aid in weight loss

19. Athletes have expensive urine...
Food/Supplement
Approx. $/kg
G Protein/$1.00
Beef, ground
4.38 46
Chicken breasts
7.69 30
Nonfat milk
0.66 48
Eggs
1.58 76
High PRO Bars
20-25
13 (8-17) (10-34)
Whey PRO-IEW
40-50
20 (14-24) (18-48)
Soy Powders 27
31 (29-33) (38-62)
Mean Repl. Powders
21-34
17 (10-24) (12-48)

20. Protein Needs in Athletes
Endurance Athletes:
Recommendations, agreed upon by most researchers:
g/kgBW
For 130lbs person (1.5g/kgBW)= 88g
For 180lbs person (1.5g/kgBW)= 122g

21. Branched Chain Amino Acids
BCAA levels can increase the availability of carbohydrates and help protect the muscles from exercise-induced protein breakdown.
improve protein synthesis
both mental and physical performance were improved by an intake of BCAAs during a marathon

22. Protein Needs in Resistance Training
no clarity about how much “extra” protein a strength athlete needs.
The goal of the resistance trained athlete is to be in positive protein balance after exercise and promote muscle synthesis
The general consensus is that a general increase in dietary protein intake will promote muscle growth

23. What about those Carbohydrates?
The effect of timing...
If feeding is delayed by 24hours net protein balance is negative and no muscle hypertrophy occurs.
CHO/PRO consumption during exercise...