1. Topic 14: Diet and Physical Fitness Brian Spurrell
BMS208 Human Nutrition
Topic 14: Diet and Physical Fitness
Brian Spurrell

2. Fitness: Physical Activity, Nutrients, and Body Adaptations

3. Objectives List the benefits of regular physical activity.
Explain the components of fitness and conditioning.
Describe the energy systems of physical activity, including ATP and CP.
Describe the use of glucose and glycogen as body fuels during exercise.
Describe a diet to minimize glucose depletion during exercise.
Explain the principle of carbohydrate loading, including the diet to build glycogen stores.
Explain the role of dietary and body fats during prolonged exercise.
Describe the uses of protein during exercise and determine the protein needs of the athlete.
Discuss the roles of vitamin E and iron in the athlete.

4. Objectives
Explain sports anaemia and the iron requirements for the athlete.
Discuss fluid needs of the athlete and the symptoms and consequences of inadequate intake.
Describe the hydration schedule for physical activity and the need for electrolyte replacement.
Discuss the effects of caffeine and alcohol on an athlete’s performance.
Plan meals for pre-game and post-game to promote health and performance.
Define ergogenic and identify products classified as ergogenic aids.
Identify supplements commonly used by the athlete and discuss their safety and efficacy.
Identify the hormonal supplements that are promoted to athletes and are illegal or dangerous.

5. Fitness

6. Fitness involves physical activity or exercise
The components of fitness are
Cardio-respiratory endurance
Flexibility
Muscle strength
Muscle endurance
All of these characteristics describe a healthy body
Today’s world encourages sedentary lifestyles that foster the development of several chronic diseases.
Fitness involves physical activity or exercise

7. Benefits of Fitness The list is long!!! Restful sleep
Nutritional health
Optimal body composition
Optimal bone density
Resistance to colds and other infectious diseases
Low risks of some types of cancer
Strong circulation and lung function
Low risk of cardiovascular disease
Low risk of type 2 diabetes
Reduced risk of gallbladder disease in women
Low incidence and severity of anxiety and depression
Long life and high quality of life in the later years

8. W&R, Figure 14-1, p. 479

9. Fitness guidelines The 2005 Dietary Guidelines for Americans
People need to participate in 30 minutes of physical activity most days of the week for health benefits and 60 minutes to maintain a healthy body weight.
Developing Fitness
Guidelines for conditioning that are achieved through training.
Table 14-1 is the summary provided in your text
Cardio-respiratory Endurance
Frequency – 3-5 days per week
Intensity – 55-90% maximum heart rate
Duration – minutes
Fitness guidelines

10. Guidelines for conditioning
Strength
Frequency – 2-3 days per week
Intensity – enough to enhance muscle strength, muscle endurance, and improve body composition
Duration – 8 to 12 repetitions of 8 to 10 different exercises
Flexibility
Intensity – enough to develop and maintain a full range of motion
Duration – 4 repetitions of seconds per muscle group
Guidelines for conditioning

12. Developing Fitness The Overload Principle
Slightly increase comfortable capacity in each area.
(This is also called the progressive overload principle)
Increase frequency
how often an activity is performed
Increase intensity
the degree of exertion while exercising
Increase duration
the length of time
Developing Fitness

13. Developing Fitness The Body’s Response to Physical Activity
Hypertrophy is muscle gain in size and strength, the result of repeated work.
Atrophy is muscle loss in size and strength, the result of lack of activity.
Other Tips
Be active all week.
Use proper equipment and attire.
Use proper form when exercising.
Include warm-ups and cool-downs.
Challenge yourself, but not every time you exercise.
Pay attention to body signals.
Build intensity slowly.
Developing Fitness

14. Fitness – Cautions on starting
Healthy people can start with a moderate exercise program without seeking medical advise first.
People with risk factors may need medical advice.
Major risk factors
Family history of heart disease
Cigarette smoking (depletion of GSH)
Hypertension (too much salt?)
Serum cholesterol (> 5.2 mmol/L or HDL < 1.04 mmol/L)
Diabetes (insulin resistance/prediabetes?)
Sedentary lifestyle
Obesity (BMI ≥ 30)
Fitness – Cautions on starting

15. Cardio-respiratory Endurance
Cardio-respiratory conditioning
Measured by maximum oxygen uptake (VO2max).
Increases cardiac output and oxygen delivery
Increases stroke volume
Slows resting pulse
Increases breathing efficiency
Improves circulation
Reduces blood pressure
Cardio-respiratory Endurance

16. The respiratory system delivers oxygen to the blood.
Air (O2, CO2), other gases
The respiratory system delivers oxygen to the blood. 1 O2
CO2 O2
CO2
The circulatory system carries oxygenated blood throughout the body. 2 O2
The blood carries the carbon dioxide back to the lungs.
CO2 4 O2
CO2
The muscles and other tissues obtain oxygen from the blood and release carbon dioxide into it. 3
W&R, Fig 14-2, p. 483

17. Cardio-respiratory Endurance
Muscle Conditioning
Muscles use oxygen efficiently.
Muscles can burn fat longer.
A Balanced Fitness Program
Individualised – one size does not fit all!
Cardio-respiratory
Muscle strength and endurance
Flexibility
Choose an activity you enjoy
Cardio-respiratory Endurance

19. Weight Training Also called resistance training Builds lean body mass
Increases muscle strength and endurance
Prevents and manages cardiovascular disease
Enhances psychological well-being
Maximises and maintains bone mass
Enhances performance in other sports
Weight Training

20. Energy Systems, Fuels, and Nutrients to Support Activity

21. Energy Systems, Fuels, and Nutrients to Support Activity
The mixture of fuels used during physical activity depends on
Diet
Intensity and Duration of the activity
Training
Well-nourished active people and athletes do not need nutritional supplements.
Water, iron and sodium are nutrients that may need attention.
Energy Systems, Fuels, and Nutrients to Support Activity

22. The Energy Systems of Physical Activity—ATP and CP
ATP is adenosine triphosphate
a high-energy compound that delivers energy instantaneously.
CP is creatine phosphate
a high-energy compound in the muscles, used anaerobically.
Replenishes ATP
Remember
During rest: ATP + creatine  CP
During activity: CP  ATP + creatine
The Energy Systems of Physical Activity—ATP and CP

23. Fuels used vs Activity Extremely intense activity
8-10 seconds
ATP-CP (immediately available)
No oxygen needed (anaerobic)
Activity example – 100 metre dash, shot put
Very highly intense activity
20 seconds to 3 minutes
ATP from carbohydrate (lactic acid)
Activity example – 400m run at maximum speed
Fuels used vs Activity

24. Fuels used vs Activity Highly intense activity
3-20 minutes
ATP from carbohydrate
Oxygen needed (aerobic)
Activity example – cycling, swimming, running
Moderately intense activity
More than 20 minutes
ATP from fat
Activity example – hiking
Fuels used vs Activity

25. Glycogen Diet Affects Glycogen Storage and Use
High-carbohydrate diets increase glycogen stores
A Study of three groups of runners (Figure 14-3)
Normal mixed diet
High-carbohydrate diet
No-carbohydrate diet (fat and protein)
High carbohydrate diet => Enhanced endurance!
Intensity of Activity Affects Glycogen Use
Moderate activities use glycogen slowly.
Intense activities use glycogen quickly.
Glycogen

26. W&R Fig 14-3, p. 486

27. Glycogen and glycolysis
Lactate
Product of glycolysis => muscle ‘tiredness’
During highly intense activities lactic acid accumulates and activity can only be maintained for 1-3 minutes.
Low intensity activities can clear lactic acid from the blood.
Lactate is converted to glucose in the liver (Cori cycle).
Duration of Activity Affects Glycogen Use
First 20 minutes – primarily use glycogen
After 20 minutes – use glycogen and fat
Glycogen and glycolysis

28. Glucose Depletion “Hitting the wall” – exhaustion of glucose stores
Maximising Glucose Supply
High-carbohydrate diet – 8 g/kg body weight or 70% of total energy intake (normal is 5g/kg)
Glucose during activities if activity last longer than 45 minutes (sports drinks, diluted fruit juice)
Eat approximately 60 g of high-carbohydrate foods after activity.
Carbohydrate loading is a regime of diet and exercise that maximizes glycogen storage.
It is also called glycogen loading or glycogen super compensation. (See text p 488).
Glucose Depletion

29. Glucose THE fuel? Glucose during Activity Glucose after Activity
Those lasting longer than 45 minutes
Light carbohydrate snacks under 840kJ
Glucose after Activity
High-carbohydrate meal within 15 minutes accelerates glycogen storage by 300%
High-carbohydrate meal within 2 hours and rate of glycogen storage declines by half
High-glycaemic index foods
Glucose THE fuel?

30. Glycogen/Glucose & Training
Training Affects Glycogen Use
Untrained muscle cells depend more heavily on anaerobic pathways (glycogen).
Muscles that repeatedly deplete glycogen through hard work will store greater amounts of glycogen.
Conditioned muscles rely less on glycogen and more on fat for energy.
Trained muscle cells have more mitochondria and can use oxygen better.
Glycogen/Glucose & Training

31. Fat! Duration of Activity Affects Fat Use
Beginning of activity uses fatty acids in the blood
After 20 minutes, uses body fat as major fuel
Intensity of Activity Affects Fat Use
As intensity increases, fat makes less of a contribution to the fuel mix
Must maintain aerobic metabolism … respiratory fitness!
Steady as she goes!
Oxygen must be abundant to break down fat
Remember … fats are highly reduced and must be oxidised!
Fat!

32. Fat use in activity Training Affects Fat Use
In a similar manner to glucose use …
The better trained the muscles, the more fat is used
The better trained, the stronger the heart and lungs to deliver oxygen
If better trained, then hormones prevent glucose release from the liver, so they rely more on fat
Fat use in activity

33. Protein Protein Used in Muscle Building Protein Remodelling
Synthesis of protein is suppressed during activity.
After activity protein synthesis accelerates.
Repeated activities cause body adaptations to support needs.
Protein Remodelling
Genetics – protein structures rebuilt to adapt to changes
Daily, 7 to 28 grams of body protein is added to muscle mass during muscle-building phase.
Protein

34. Protein Protein Used as Fuel Diet Affects Protein Use during Activity
During physical activity muscles use amino acids for fuel.
10% of total fuel used
Diet Affects Protein Use during Activity
Diets rich in energy and carbohydrate allow the body to use less protein for fuel.
Carbohydrates spare protein.
Protein

35. Protein Intensity and Duration of Activity Affect Protein Use
If glycogen stores get depleted, then more reliance on protein
Anaerobic strength training demands more protein to build muscles but not large amounts.
Training Affects Protein Use
The more trained the less protein used for energy
Protein

36. Protein – how much? Protein Recommendations for Active People
Athletes in training need more protein than sedentary people.
Athletes in training need to meet energy and carbohydrate needs first.
Adult RDA: for males 56 g/day, for females 44 g/day
Strength athletes: for males g/day, females g/day
Endurance athletes: for males g/day, females g/day
U.S. average intake of protein: for males 95 g/day, females 65 g/day
Protein – how much?

37. Vitamins & Minerals Supplements Do not enhance performance
Deficiencies may impede performance
Timing makes a difference; supplements take hours or days to combine with cells.
Nutrient-dense foods provide nutrients needed.
Vitamins & Minerals

38. Vitamins & Minerals? Vitamin E Iron Does not improve performance
Protects against oxidative stress (exercise-induced?)
More research needed
Vegetables oils and antioxidant fruits and vegetables
Iron
Iron losses in sweat
Small blood losses in digestive tract
Poor iron absorption – due to low bioavailability
Vitamins & Minerals?

39. Iron Iron Deficiency Iron-Deficiency Anaemia
Common in physically active young women
Especially distance running
Low intakes of iron-rich foods
Menstruation
Consume good dietary sources of iron
Fortified cereals, legumes, nuts and seeds (include vitamin C)
Iron-Deficiency Anaemia
Impairs physical performance
Low haemoglobin/myoglobin => less oxygen available
Cannot perform aerobic activity and tire easily
Iron

40. Iron – how much? Sports Anaemia Iron Recommendations for Athletes
Low blood haemoglobin for a short time (temporary)
Adaptive, temporary response to endurance activity
Activity destroys older/fragile RBCs
Does not require supplementation
Iron Recommendations for Athletes
Review Ch 13 for details on Fe.
Blood tests should guide the decision (see Appendix E)
Depends on the individual
Iron – how much?

41. Fluids and Electrolytes

42. Fluids & Electrolytes Fluid Losses via Sweat Hyperthermia
Muscle heat is x greater when active than at rest
Cooling mechanism
Sweating prevents temperature rise
1 litre of sweat dissipates 2520 kJ of heat
Prevents up to 10°C rise in body temp!
Hyperthermia
An above-normal body temperature
Body heat builds up
Triggers maximum sweating without sweat evaporation
Minimal cooling! Danger!
Fluids & Electrolytes

43. A dangerous accumulation of body heat with accompanying loss of body fluid
Symptoms of heat stroke
Headache
Nausea
Dizziness
Clumsiness
Stumbling
Hot, dry skin
Confusion or other mental changes
Heat Stroke

44. Heat Stroke Prevention of heat stroke Drink fluids
Rest in the shade when tired
Wear appropriate clothing
Heat Stroke

45. Hypothermia Hypothermia – a below-normal body temperature Symptoms
Shivering and euphoria
Weakness, disorientation, and apathy
Prevention
Drink fluids
Wear appropriate clothing
Water Recommendations (convert these to SI!)
1.0 to 1.5 mL/kcal expended
½ cup per 100 kcal expended
Hypothermia

46. Fluids Fluid Replacement via Hydration
Full hydration is imperative for athletes.
Be aware of hourly sweat rate - replace lost fluids.
Plain, cool water is recommended.
Endurance athletes may require carbohydrate-containing beverages.
Hydration schedule (convert these to SI units!)
Two hours before activity – 2-3 cups
15 minutes before activity – 1-2 cups
Every 15 minutes during activity – ½-2 cups
After activity – 2 cups for every lb of body weight lost
Fluids

47. Fluids and Electrolytes - losses
Electrolyte Losses and Replacement
Greater in the untrained
Training improves electrolyte retention.
Eat regular diet meeting energy and nutrient needs.
Endurance athletes may need sports drinks.
Salt tablets worsen dehydration and impair performance.
Fluids and Electrolytes - losses

48. Fluids and Electrolytes - problems
Hyponatraemia
Decreased concentration of sodium in the blood
Causes
Excessive sweat
Over-hydration
Drinking sports drinks during an activity
sports drinks offer low sodium and glucose polymers
Fluids and Electrolytes - problems

49. Hyponatraemia! Symptoms of hyponatraemia Prevention Severe headache
Vomiting
Bloating
Confusion
Seizure
Prevention
Replace sodium during prolonged events.
Do not restrict salt in diets the days before events.
Hyponatraemia!

50. What should I drink? Poor Beverage Choices: Caffeine and Alcohol
Caffeine is a stimulant.
Alcohol is not the beverage to replace fluids and carbohydrate.
What should I drink?

51. Diets for Physically Active People

52. Diets for Physically Active People
A diet that provides
ample fluids and
nutrient-dense foods
to meet energy needs
will enhance an athlete’s activity and overall health.
Pregame and postgame meals should be
light and
carbohydrate rich.
Diets for Physically Active People

53. Choosing a Diet to Support Fitness
Water
Thirst mechanisms are not as reliable
Must be replenished
Nutrient Density
Consume nutrient-dense foods that are
high in carbohydrate,
moderate in fat, and
adequate in protein
Choosing a Diet to Support Fitness

54. Choosing a Diet to Support Fitness
Carbohydrate
60-70% total energy intake
Avoid fibre-rich foods in the pre-game meal.
Added sugar and fat may be needed during intensive training.
Liquid supplements should not replace foods.
8-10 g carbohydrate/kg body weight during heavy training
Choosing a Diet to Support Fitness

55. Diets for Physically Active People
Protein
Strength athletes:
for males g/day, females g/day
Endurance athletes:
for males g/day, females g/day
A Performance Diet Example
Total kJ – (per day)
63% kcal from carbohydrate
22% kcal from fat
15% kcal from protein
All vitamin and mineral RDAs are met
Diets for Physically Active People

56. W&R, Fig 14-4, p. 498

57. Meals Before & After Competition
Pregame Meals
Fluids
1260 – 3360 kJ
Carbohydrate-rich foods low in fat and fibre
Light and easy to digest
Postgame Meals
High-carbohydrate meals
Liquids often preferred
Meals Before & After Competition

58. W&R, Fig 14-5, p. 498

59. Supplements
Performance-Enhancing Aids

60. Performance-Enhancing Aids?
It is difficult to distinguish valid versus bogus claims about ergogenic aids.
Many individuals believe these drugs, supplements, or procedures will enhance physical performance in activities.
Some are harmless, some have dangerous side effects, and some are costly.
Most do not meet claims.
Marketing techniques are used to generate sales.
Performance-Enhancing Aids?

61. Ergogenic Aids? Substances promoted as ergogenic aids
Arginine – a nonessential amino acid
Boron – a nonessential mineral
Brewer’s yeast is falsely promoted as an energy booster.
Cell salts are sold as health promoting.
Co-Q10 is not effective in improving athlete performance.
DNA is falsely promoted as an energy booster.
Epoetin is illegally used to increase oxygen capacity.
Ergogenic Aids?

62. Ergogenic Aids? More substances promoted as ergogenic aids
Gelatin is not a strength enhancer.
Ginseng has many side effects.
Glycine – a nonessential amino acid
Growth hormone releasers do not enhance performance.
Guarana - high doses can stress the heart and cause panic attacks.
Herbal steroids (plant sterols) do not enhance hormone activity.
HMB (beta-hydroxy-beta methylbutyrate) claims to increase muscle mass and strength.
Inosine has been shown to reduce endurance of runners.
Ergogenic Aids?

63. Ergogenic Aids Ma huang has many dangerous side effects.
Niacin does not enhance performance and has side effects.
Octacosanol has false promotions.
Ornithine – a nonessential amino acid
Oryzanol – a plant sterol
Pangamic acid does not speed oxygen delivery.
Phosphate pills do not extend endurance or increase efficiency of aerobic metabolism.
Pyruvate has common side effects of gas and diarrhoea.
Ergogenic Aids

64. Ergogenic Aids Ribose has some false claims.
RNA (ribonucleic acid) does not enhance performance.
Royal jelly is falsely promoted.
Sodium bicarbonate may cause intestinal bloating and diarrhoea.
Spirulina is potentially toxic.
Succinate is not a metabolic enhancer.
Superoxide dismutase (SOD) is useless; it is digested.
Wheat germ oil is not an energy aid.
Ergogenic Aids

65. Dietary Supplements Carnitine Chromium Picolinate
Non-essential nutrient
Facilitates transfer of fatty acids across mitochondria membranes
Supplementation does not increase
muscle carnitine or
enhance exercise performance.
Chromium Picolinate
Essential mineral in carbohydrate and lipid metabolism
Supplementation has no effect on
strength,
lean body mass, or
body fat.
Dietary Supplements

66. Dietary Supplements Complete Nutrition Supplements Creatine
Taste good and provide food energy, but do not provide complete nutrition
Should not replace regular meals
Creatine
Some studies suggest improvement in muscle strength and size, cell hydration and glycogen loading capacity
Safety issues and side effects
Dietary Supplements

67. Dietary Supplements Conjugated Linoleic Acid (CLA) Caffeine
Derived from linoleic acid, an essential fatty acid
Increases lean body mass in animals
Few human studies have been performed.
Caffeine
Caffeine can enhance performance by stimulating fatty acid release.
Adverse effects include stomach upset, nervousness, irritability, headaches, and diarrhoea.
Use in moderation.
Use as an addition to other fluids, not as replacement.
Oxygenated Water
Oxygen cannot enter the bloodstream by way of the GI tract.
The body gets oxygen from the lungs.
Dietary Supplements

68. Hormonal Supplements Anabolic Steroids Illegal Authorities ban use
Plant sterols from herbs are poorly absorbed.
Dangerous side effects on the body and the mind
Hormonal Supplements

71. Hormonal Supplements DHEA (dehydroepiandrosterone) and Androstenedione
Hormones that are precursors to testosterone
No evidence to support claims
Short-term effects are identified
Human Growth Hormone (hGH)
Used to build lean tissue and increase height if still growing
Extremely high cost
Many adverse side effects
Hormonal Supplements

73. Any Questions?