1. Chapter 11
Nutrition and Fitness

2. Objectives for Chapter 11
List and describe the five basic components of fitness.
Describe the benefits of regular physical activity.
Describe the FITT principle and how to use it to create a fitness program.
Describe the roles of carbohydrate, fat, and protein during physical activity.
List the optimal food sources before, during, and after exercise.
Importance of Vitamins, Minerals and fluids
List and describe ergogenic aids that claim to improve athletic performance and physical fitness.

3. 1. What Is Physical Fitness and Why Is It Important?
What does it mean to be physically fit?
Lawn Mower story
Criteria:
Cardiorespiratory endurance: ability to sustain cardiorespiratory exercise for extended time.
Muscle strength: ability to produce force for brief time.
Muscle endurance: ability to exert force for a long period of time without fatigue
Flexibility: range of motion around a joint
Body composition: proportion of muscle and fat

4. 2.
Over half of adults in United States do not meet regular physical activity recommendations
Table 11.1

5. 2.
Table 11.1 (continued)

6. 2. Kleiber’s Law: Vitamins & Exercise
Paradox: If set number of heart beats, how come exercise is good for you?

7. 3. Being Fit
Rate of perceived exertion (RPE) measures intensity of cardiorespiratory exercise
Repetitions of maximum (RM) refers to intensity of weight training
Dietary Guidelines for Americans recommends at least 30 minutes of moderate-intensity physical activity most days for moderate health benefits
60 to 90 minutes daily to lose weight effectively
Table 11.3

8. 3.
Table 11.2

9. 3. How fit are you?
Take your pulse on the inside of your wrist, on the thumb side. Use the tips of your first two fingers (not your thumb) to press lightly over the blood vessels on your wrist. Count your pulse for 10 seconds and multiply by 6 to find your beats per minute.
For children 10 years and older, and adults (including seniors) is beats per minute
Well-trained athletes is beats per minute.

11. 4. How Are Carbohydrate, Fat, and Protein Used during Exercise?
That first burst of energy
comes explosively from the breakdown of:
Adenosine triphosphate (ATP)
Creatine phosphate
Limited amount stored in cells
This is anaerobic energy production (without oxygen).

12. 4. Energy Metabolism
Figure 11.2

13. 4. Switching Gears
After the initial burst of energy the body takes its next fastest source of energy: Glucose.
Glucose comes from:
Blood (25 Grams),
Muscle (525 grams Glycogen)
Liver (100 grams Glycogen)
Will provide 2 hours of fast energy
Glucagon will do the opposite of Insulin

14. 4. Switching Gears Remember brain, red blood cells only uses glucose
When your muscles are well trained, they have the ability to store 20 to 50% more glycogen than untrained muscles.
More glycogen means more fuel for muscles.

15. 4. The Big Switch
After minutes into exercise muscle glycogen starts to deplete and body switches to fat. (you can feel this switch!)
This “switch” depends on age, fitness level and Stimulant (caffeine)
Muscle, liver and blood glucose is limited, fat is not.
Carbohydrates are always used for energy but their % use relative to fat increases with intensity.
Note: Diet recommendation has 50% carbs, 30% fat and 20% protein.

16. 4. The Big Switch

17. 4. Fat Sources & Maximizing Fat Loss
Fat is the primary energy source during low-intensity exercise.
Two forms: fatty acids (from triglycerides) in adipose tissue and muscle tissue
Converting fatty acids into energy is slow and requires more oxygen compared with carbohydrate
Low-intensity exercise uses mostly fat from adipose tissue
Moderate-intensity exercise also uses fatty acids from muscle triglycerides
Well-trained muscles burn more fat than less trained muscles

18. 4. Varying Intensities of Exercise
Figure 11.3

19. 4. High intensity leads to Lactic Acid
Carbohydrate use will produce Lactate. At low amounts, the body converts Lactate to energy. At high intensity, Lactic acid builds up and negatively affects muscle use. Think soreness.

20. 4. High intensity vs low intensity
Source of energy: High carbs low fat
Lactic acid build up
More calories burned given the same amount of time.
Higher heart rate= Cardiovascular benefits
Low Intensity
Source of energy: High fats and low carbs.
No Lactic build up
Less calories burned given the same amount of time.
Little cardiovascular benefits

21. 4. How Are Carbohydrate, Fat, and Protein Used during Exercise?
Fat-burning zone: 65 to 73 percent of maximum heart rate
“Cardio” zone: >73 percent of maximum heart rate
What is the best way to lose fat?
Low intensity workouts vs high intensity workout
THE TRUTH ABOUT THE FAT BURNING ZONE p. 422

22. 4. And Finally…Protein
Protein is primarily needed to build and repair muscle
Muscle damage results from exercise, especially in weight or strength training
Amino acids needed to promote muscle growth and recovery
Body can use protein for energy but prefers carbohydrate and fat as main energy sources
Amino acids are converted to glucose in liver

23. 5. How Are Carbohydrate, Fat, and Protein Used during Exercise?
Variables
Duration
The longer the workout, the more Glycogen needed
Intensity
The higher the intensity, the more Glycogen is needed
Type
Strength training does not signify higher protein uptake.
Timing
Consuming when and what matters!
The amount of Calories depends on what occurs with your weight as you work out.

24. 5. Eating Before Exercise
Need to maximize Glycogen storage, give muscles immediate energy. But need adequate time for digestion.
1 to 4.5 grams of Carbohydrates per kg consumed one to several hours before.
Consuming protein before exercise as well as during exercise increases muscle glycogen synthesis and protein synthesis after exercise is over
High-fat foods should be avoided before exercise: takes longer to digest, may cause stomach discomfort and sluggishness.
Calculations:

25. 5. Eating During Exercise
For exercise >1 hour, begin carbohydrate intake shortly after start and every 15 to 20 minutes
30 to 60 g carbohydrate/hour to avoid fatigue
Glucose, sucrose, maltodextrin are best choices for quick absorption
Avoid fructose which can cause GI problems
Consuming both carbohydrate and protein is best for muscle maintenance and growth
So….Sports drinks!

26. WOO = Window of Opportunity
5. After Exercise
WOO = Window of Opportunity
Within the first 30 – 45 minutes:
Muscles are most receptive to storing Glycogen
Greater muscle protein synthesis.
Combination of intake of both Carbohydrates and Protein causes a larger increase in Glycogen synthesis
Best combination is a 3:1 carbohydrate : protein ratio
Something that is absorbed quickly:
whey protein (in milk) is absorbed rapidly and contains all essential amino acids needed mixed with chocolate
Peanut butter sandwich,
pizza

27. 5. Carbohydrate Loading
If Glycogen storage gets depleted then concentrating carbohydrates will boost storage
Misc 11.4

28. 6. What Vitamins and Minerals Are Important for Fitness?
Using more oxygen during exercise increases free radicals that damage cells
Supplements of antioxidant vitamins E and C not shown to improve athletic performance nor decrease oxidative stress in highly trained athletes
Some minerals can be of concern in highly active people: Iron and Calcium
Iron deficiency very common in athletes
Benefits of exercise on bone growth only relevant when there is adequate amounts of Calcium

29. 6. How Does Fluid Intake Affect Fitness?
Fluid and electrolyte balance and body temperature affected by exercise
Water is lost through sweat and exhalation.
Sodium and chloride, and to lesser extent potassium, are electrolytes lost in sweat
Electrolyte imbalance can cause heat cramps, nausea, lowered blood pressure, edema
Evaporation of sweat helps cool body
Hot, humid weather reduces evaporation and body heat increases: increases risk of heat exhaustion and heat stroke

30. 6.
Table 11.5

31. 6. How Does Fluid Intake Affect Fitness?
You need fluids before, during, and after exercise
Sports drinks contain 6 to 8 percent carbohydrate and sodium and potassium: beneficial in long endurance events
For events <60 minutes, water is sufficient to replace fluids and food to replace electrolytes.
Sports drinks should be avoided as a daily beverage.
Not recommended during physical activity: fruit juice (carbohydrate concentration too high); carbonated drinks (can cause bloating); alcohol, caffeine: diuretics and side effects

32. 6. Consuming Too Little or Too Much Fluid Can Be Harmful
Thirst not a good indicator of fluid needs for athletes.
Acute dehydration: when not adequately hydrated before strenuous exercise
Chronic dehydration: when not adequately hydrated over extended period of time
Fatigue, muscle soreness, poor recovery from workout, headaches, nausea, dark urine
Hyponatremia: low sodium blood levels due to consuming too much water without electrolytes

33. 6. Effects of Dehydration on Exercise Performance
Figure 11.4

34. 7. Can Dietary Supplements Contribute to Fitness?
Dietary supplements are not strictly regulated by FDA
Manufacturers not required to prove safety or efficacy of supplement claims
Dietary supplements and ergogenic aids may improve performance, but can have side effects
Creatine: research data mixed regarding enhancement of performance
Improves high-intensity, short-duration activities (like weight training) that rely on anaerobic metabolism

35. 7. Can Dietary Supplements Contribute to Fitness?
Caffeine enhances athletic performance, mostly during endurance events.
Stimulates central nervous system, breakdown of muscle glycogen, may increase fatty acid availability
Improves high-intensity, short-duration activities (like weight training) that rely on anaerobic metabolism
Considered a banned substance by some athletic associations

36. 7. Can Dietary Supplements Contribute to Fitness?
Anabolic steroids: testosterone-based substances that promotes muscle growth and strength (anabolic effect)
Androgenic effect (testosterone-promoting): hormone imbalance causes undesirable side effects in both men and women and health risks
Growth hormone: little research on effects on athletic performance, results mixed
Reduces body fat but not muscle strength
Excess can cause acromegaly and serious health issues

37. 7. Summary
Table 11.7

38. Misc. “No Oven Needed” Energy Bars
Figure 11.5

39. 7. Workout Myths
Table 11.8