Performance Nutrition
Clyde Wilson, Nutrition Intern
Health Promotion Services
Stanford University
13 May 2002
Notes to Tribe Members:
1. The slide entitled “Ironman” (slide #17) is a summary of information
from the reference under the heading (on slide #17). This review
article has tons of information on untraendurance triathlons and I
recommend it to everyone. I gave a copy of this paper to Jesse.
2. In my talk I stated that the amount of salt in 1 L of water during
training should be between ¼ and ½ teaspoons, and at other times said
“just under ½ teaspoon”. I measured it all out again today more
carefully: 1 g sodium (2.5 g table salt) is 1/3 teaspoon.
My sincere apologies for the confusion. My handout stated “1/2
teaspoon”. Please put 1/3 teaspoon.
3. This power point does not include my overheads of graphs, images, and
cover pages copied directly from research papers. In my opinion these
are the most poignant overheads because they show some of the
sources from which I have gathered information. Nonetheless, I hope
this power point will be helpful to you.
4. I look forward to telling you about food on the July 10th.
muscle contraction
glucose: WHY WE EAT
to other muscles
or to bloodstream
ATP
pyruvate
ADP
lactate
aerobic
TCA
mitochondrion
produces electron current which
produces proton current which
produces ATP
4 e-1 + 4 H+ + O2  2H2O
carnitine
fat:
WHY
WE EAT
WHY WE BREATH
Ion currents in neurons, muscle, and mitochondria produce
MEMBRANE (lipid) free radicals. Combat this with vitamin E
and C.
E
membrane
lipids
E
radical
C
radical
C
Caffeine
possible mechanism:  adrenalin (fat burning, heart stroke volume)
 beta endorphins (less pain)
Int. Olympic Committee: NTE 12 g/ml urine (~3 cups coffee)
3 and 6 mg/kg  time to exhaustion @ 85% VO2 by 22%,
9 mg/kg did NOT (no “dose response”) J Appl Physiol 1995 (78) 867074
5, 9 and 13 mg/kg each  time to exhaustion @ 80% VO2 by 23%
(again, no “dose response”) but only 5 mg/kg < 12 g/ml urine
Int J Sports Med 1995 (16) 225-30
effects negated by coffee
peak blood [caffeine] 1 hour after intake
half-time in body 4-6 hours
CONCLUSION: 3 mg/kg body weight caffein (not coffee)
1 hour prior to competition
Taurine:
no studies related to exercise performance (I’m aware of)
inhibits artherosclerotic lesions in mice
Clin Exp Pharmacol Physiol 2001 (10) 809-15
 oxidative stress to nerves
Exp Neurol 2001 (172) 211-9
J Neurosci Res 2001 (66) 612-9
nerve growth in infants
Nutr Neurosci 2001 (4) 439-43
oxidative stress in liver in rats
Hum Exp Toxicol 2001 (20) 251-4
in endoplasmic reticulum in rats
in myocardium in guinea pigs
related to age in rats
memory in mice
Circulation 2001 (104) 1165-70
Free Radical Biology & Medicine 1995 (19) 461-71
Biochem Pharmacol 2001 (62) 29-39
Neual Plast 2000 (7) 245-59
plasma [taurine]  19% after 90 min @ 75% VO2, 77% after
Marathon, 36% after 100 km run i.e.  intensity (muscle breakdown)
Red Bull
caffeine, taurine, and glucuronolactone (vit. C precursor)
alertness, memory
Seidl R, Peyrl A, Nicham R, and Hauser E. Amino Acids 2000 (19) 635-42
Alford C, Cox H, and Wescott R. Amino Acids 2001 (21) 139-50
Warburton DM, Bersellini E, and Sweeney E. Psychopharmacology 2001 (158) 322-8
 cardiac stroke volume by 22%
Bauin M and Weiss M. Amino Acids 2001 (20) 75-82
my opinion: only the caffein has immediate effects on performance
(taurine and vit. C reduce oxidative damage and
improve performance the next day, week, etc)
B vitamins needed to metabolize CHO, fat, & aminos. Calories
taken in during training are typically low in B vitamins.
B1 (thiamine) needed for TCA cycle, membrane/nerve conduction
TOXICITY: none orally, 100xRDA intravenous  convulsions, anaphylactic shock
B2 (riboflavin) needed for TCA cycle, no reported toxicity
B3 (niacin/nicotinimide) the “N” in NAD+/NADH
TOXICITY: >1 g/day (RDA=16 mg) harms liver and skin
B6 (pyridoxine) needed for amino acid metabolism
TOXICITY: >0.2 g/day (RDA=1.3 mg) causes numbness, impaired reflexes, sensory
nerve and spinal dorsal root ganglia degeneration
B12 (cobalamin) needed for TCA cycle, no toxicity reported
Pantothenic Acid, 1/3 of CoA molecule, no toxicity reported
Zinc: intake may be low for athletes (fatigue,  endurance,  T,
weight loss, bone loss) but excess intake (> 2x RDA) can cause
Copper deficiency (impaired immunity, enzyme activity, bone loss)
Carnitine: 4 g /day did not improve Marathon time for 7 athletes
but did  mitochondrial enzyme activity in 14 athletes
2 g /day for 6 months prevented  in carnitine in 24 athletes
 PDH activity, but did not  fat transfer activity
most research shows no change in VO2 max or RQ
the few which do involve highly trained athletes
Phosphatidylserine has shown benefits for neurological membranes.
DEHYDRATION by 1 Quart INHIBITS:
gastric emptying (by 50%; exercise-induced nausea)
food intake (dehydration-associated anorexia)
gene expression, hormonal control, growth
endurance (3/4 time to exhaustion)
strength (by 5%)
kidney function
protein turnover in liver (by 25%)
perception and short-term memory (myelin tubules)
Hydration throughout the day:
1 Quart water / 1000 Calories of food
example: 2000 Cal food  you need 2 quarts of water  8 cups
3000 Cal food  you need 3 quarts of water  12 cups
Soda and Fruit Juice: ~100 Cal / 8-ounce cup
Only 2/5 of volume counts towards hydration for food.
Instead of 12 cups (3/4 gallon) of water for a 3000 Cal diet,
you would need 30 cups (nearly 2 gallons) of soda or
fruit juice, which would in itself contain at least 3000 Cal,
so that you end up eating and drinking 6000 Cal per day.
Hydration during exercise:
drink 1.5 times the amount you lose in perspiration with
1/3 teaspoon of salt per quart of water that you drink.
Pure water will NOT
hydrate you during exercise
unless taken with food containing electrolytes:
this is because the body needs to replace both
salts and water when you exercise.
When not exercising, drink pure water because this
water is to digest your food, not to replace perspiration
losses. Natural salt in food replaces normal perspiration.
Pure water
throughout the day.
Electrolytes
when you exercise.
Dehydration achieved by:
1. not drinking pure water throughout the day as food digest
2. drinking water only with meals
3. not taking in salts with water during exercise
Tips:
1. drink water BEFORE your morning diuretic coffee
2. carry a water bottle
3. have a sports drink or a small container with salts
in your gym bag, OR eat food containing salt after exercise
If all the water you drink goes straight to your bladder but you
are still thirsty, you are either low or high in salt, or you are only
drinking with meals.
Ultraendurance sport hydration and energy intake is a different world:
You will sweat 0.5-2 L / hr but can only ingest 1-1.25 L / hour.
Sweat is ~1 g/L Na+, about 1/3 the concentration in blood.
Thus, salts in blood CONCENTRATE as you sweat.
If you are replacing < 2/3 of your sweat losses, drink pure water.
But if replacing < 2/3 of your sweat losses, you risk dehydration.
Maximizing fluid intake and minimizing sweat losses = crucial.
Maximize fluid intake: ~1 g/L Na+ i.e. ~2.5 g table salt (1/3 teaspn)
with ~ 1/5 as much potassium salts
50-75 g (200-300 cal) carbohydrates
If you can only drink < 2/3 as much as losses forget about salts.
Reducing [salt] by 5% = reduced performance, 10% = collapse.
Trained cyclists: energy burned during training.
VO2 max
g/hr energy used
carbo prot
fat
50%
137
105
13
19
70% (calculated) 208
177.5
13.5
18
80%
212
14
17
243
Sports Med 2001 (31) 701-15
You can digest fewer calories at higher VO2 but burn more.
Carb intake and glycogen stores allow you to exceed 50% VO2.
You may have gastric distress if trying to take in more than
50-75 g (200-300 cal) of carbohydrates (1/2-3/4 cup maltodextrine).
Fructose and Na+ are both co-absorbed with glucose.
Ironman
“Factors Affecting Performance in an Ultraendurance Triathlon” Laursen PB and Rhodes EC, Sports Med 2001(31)195
8-17 hours in the heat
8500-11500 cal with sweat rates up to 2 L /hr
Maintaining glycogen and thermoregulation becomes a “challenge”.
Losing body water  body cooling and causes cardiovasuclar drift.
Peak central temperature  causes  performance, central fatigue.
Eletrolytes  gastric emptying and  glucose & water absorption.
Most common reason for needing medical assistance in Ironman:
DEHYDRATION (performance  already w/ 4% weight ).
Most common electrolyte imbalance: hyponatraemia.
Tour de France
Int J Sports Med 1989 (10) S26
5500-7000 cal /day (highest recorded for event > 7 days long)
50% energy taken in during competition (lowers nutrient value, vit Bs)
69% energy during race is CHO (1/2 from liquids), 25% fat (sweets)
Up to 12 L water intake /day (~1.3 L /hr during competition).
Athletes supplemented with 2 mg B1, 5 mg B2, 2.4 mg B6, 1.6 mg C.
Syringe injections of pantothenic acid, B1, 2, 3, 6, and especially 12
(B12 levels 4x higher for those using injections).
Simulations: 13 “highly trained” cyclists
Int J Sports Med 1989 (10) S32,41,49
Normal high CHO diet can’t maintain energy balance.
Equal parts maltodextran and fructose also falls short (gastric distress).
85% maltodextrine (150 g/L), 15% fructose achieved energy balance.
We all sweat at different rates, and [salt] in sweat  w/training.
How to figure out your personal needs:
1. Weigh yourself before and after training in high and low temps.
2. Know how many liters you drank during training.
3. If you drank 1 L but still lost 1 kg in weight, you sweat 2 L.
4. Divide the amount you drank by how much sweat you lost
(in this example: drank 1 L / sweat 2 L = 0.5 or ½ ).
5. If you replace < 2/3 of your sweat losses, forget salts.
If you replace all of your sweat losses, 1/3 teaspoon table salt
with 10-20 % potassium salt.
6. 50-75 g carbs (as much as you can absorb i.e. avoid gastric distress)
7. Small amount of protein is beneficial (5-10 g / hr).
HammerGel
Goo
Cytomax
33 g packet
32 g
1 packet
100
100
CHO/sugar 28/0
protein
fat
Gatorade SustainedEnergy
0.5 L
1 scoop
160
100
111
20/4
30/17
28/28
24/2
0
0
0
0
3 (soy)
0
2
0
0
1 (lecithin)
sodium mg 15
50
140
220
0
potassium
yes
yes
154
60
0
sugar type
malto
malto
malto
sucrose
fructose
fruct/gluc
calories
add-ons
herbs
various
all but Gatorade contain BCAAs and vit. C
malto
carnitine
Most ingested sugar goes to muscle or liver initially:
muscle
dairy
lactose:
glucose + galactose
fruit/veg. sucrose:
glucose + fructose
starch dextrines:
glucose chains
liver
Bicycling magazine Oct 1997: Top bicycle racers (Indurain,
Riis, Jonker, and Tofi) increased their performance after the
achievement of an “emaciated frame” and “pipestem arms.”
This article says to lose weight by
•
hard training in the fasted state
•
eat only breakfast and dinner, go to bed hungry
•
suppress appetite with diet drugs
•
under-eat during a stage race (but not during the Tour)
Lance Armstrong’s autobiography (p. 224): “There was an
unforseen benefit of cancer…now I was almost gaunt…I had lost
15 pounds. It was all I needed [to win the Tour de France].”
CNN Presents on 5 May 2002:
“Fat Chance: America is facing an obesity epidemic.”
1. expect failure but keep trying to lose weight, weigh yourself often
2. don’t deny yourself, but mostly eat low fat & high carb
3. 5 meals /day
4. exercise 1 hour / day and add little bits of exercise throughout day
This CNN program concludes by saying that during the past 40 years
there has been obesity “research, research, and more research”
but that we are, as a society, just getting “fatter, fatter, and fatter,”
with no end in sight until
“science can help us.”
“Diets high in fat do not appear to be the primary cause of the
prevalence of excess body fat in our society, and reductions in
fat will not be a solution.”
Willett WC, Am J Clin Nutr 1998:67, 556S-62S.
Dept. of Nutrition and Epidemiology, Harvard School of Public Health
“At this stage there is no conclusive evidence from epidemiological
studies that under isoenergetic conditions dietary fat intake promotes
the development of obesity more so than other macronutrients.”
Seidell JC, Am J Clin Nutr 1998:67, 546S-50S.
Dept. of Chronic Diseases and Env. Epidemiology, National Inst. of Pub. Health, Netherlands
“Replacement of saturated fats by carbohydrates adversely affects
plasma HDL concentrations; replacement of saturated fat by
unsaturated fatty acids deserves consideration as an alternative.”
Katan MB, Am J Clin Nutr 1998:67, 573S-6S.
Dept. of Human Nutrition, Wageningen Agricultural University
insulin
1.
2.
3.
4.
shuttles nutrients into organs, keeps blood sugar down
halts the use of fat use from fat cells for energy
shuttles nutrients into fat cells so fat cells make more fat
increases LDL, total cholesterol, TGs
Refined carbohydrates cause insulin to spike in the blood.
Insulin lowers blood sugar to protect the body (coma and death).
After several weeks, the body develops insulin resistance.
Basal (24-hour, around the clock) insulin levels rise.
Your body has become a “fat storage, non-body fat burning” machine.
Insulin resistance precedes (leads to) obesity, diabetes, heart disease.
YO-YO dieting: what really happens
1. eliminate fat and calories
2. insulin spikes, lower blood sugar than ever, more hunger,
lower metabolism, insulin resistance
3. 20-40% of weight loss is normally muscle loss
4. when weight loss achieved, normal diet resumed
5. metabolism is still low and body is still insulin resistant
6. weight rebounds faster than ever
7. body even overcompensates and “stores extra fat” for
the next “fast” (diet)
8. the weight regained is all fat (the lost muscle does not return)
9. heavier and less muscle than ever before
10. go back to step (1)
Red meat has gotten a partially bum rap:
10 g/day red meat  colorectal cancer 11%, 26% if well done / very well done
or cooked with high-temp (pan fried, grilled).
“These results are consistent with the hypothesis that carcinogenic compounds
formed by high-temperature cooking techniques, such as heterocyclic amines
and polycylic aromatic hydrocarbons, may contribute to the risk of developing
colorectal tumors.” Sinha R, et al., Cancer Res 1999;59:4320-4.
“Diets containing primarily lean red meats (beef, veal, pork) and lean white
meats (poultry, fish) produced similar reductions in LDL and elevations in
HDL cholesterol levels, which were maintained throughout 36 weeks of
treatment.” Davidson MH, et al., Arch Intern Med 2000;160:395-8.
“Consumption of red meat, especially fried and/or well-done red
meat, was associated with increased risk of lung cancer.”
Sinha R, et al., Cancer Causes Control 1998;9:621-30.
Red meat and colon cancer: dietary haem, but not fat, has cytotoxic and
hyperproliferative effects on rat colonic epithelium.
Sesink ALA, et al., Carcinogenesis 2000;21:1909-15.
High (>20%) Protein Diet
heart disease (cholesterol, homocystein)
high blood pressure
purines  gout  arthritis
calcium loss  osteoarthritis
less fruit / vegetables / grains  cancer
vitamin / mineral deficiency
inhibited platelet function  bruising
fatigue
similar to diabetes: renal disease
cerebral swelling
Weight loss due to water loss and appetite suppression.
But far-northern indigenous peoples eat high protein and have,
for nearly all their history, been extremely healthy:
Elevated concentrations (by 4-13x) of plasma omega-3 polyunsat.
fatty acids among Alaskan Eskimos. Parkinson, AJ et al., Am J Clin Nutr 1994, 59, 384-8
“Marine diet was positively associated with serum HDL and blood
glucose and inversely with VLDL and TG.”
Bjerregaard, P et al., Eur J Clin Nutr 2000, 54, 732-7
“In the last 30 years, sociocultural and political changes have
profoundly affected the way of life of the Cree and Inuit or Northern
Quebec. Their health status profile has also changed.
Thouez, JP et al., Arctic Med Res 1990, 49, 180-8.
“Obesity among Inuit is as prevalent as it is in the general North
American population. This is a new development over the past two
or three decades, the result of rapidly changing physical activity, diet,
and lifestyle.” Young, TK, Hum Biol 1996, 68, 245
Protein Balance (Nitrogen Balance)
in your body is LESS a function of protein, and more a function of
1. meeting your calorie needs
2. protein efficiency after 2 weeks of exercise
How to choose your proteins:
All protein sources are healthy.
But minimize saturated fat: visible animal fat and deep-fried foods.
Examples of how easy it is to meet daily protein needs
are in the handout.
Alcohol: negative aspects
benefits to the cardiovascular system are in doubt
increased NADH/NAD+ ratio results in fatty liver, heart
vision (inhibition of retinal production)
protein, carbohydrate, and fat metabolism altered
thrombosis / stroke risk
oxidative damage to heart
dehydration
sleep / growth hormone
reduced testosterone
Alcohol has gotten some good press for the wrong reasons:
Moderate alcohol intake, increased levels of HDL and its
subfractions, and decreased risk (by 50% for moderate intake)
of myocardial infarction. Gaziano JM, et al., N Eng J Med 1993;329:1829-34
But hidden in the fine print:
“Various lipids…(HDL, TGs, etc) were added to the risk-factor
model one at a time. Similarly, we added the levels of
apolipoproteins…to determine the degree to which apolipoproteins
mediate the effect of alcohol, beyond the effect of HDL.”
Based on HDL and total cholesterol risk was ~50% less with moderate
alcohol. As soon as apolipoproteins were included in the calculation
risk was 8% MORE with moderate alcohol consumption.
Guess what was reported in the title and abstract? (see title at top
of page: alcohol decreases myocardial infarction risk)
It’s not the wine, it’s the entire diet that matters:
Moderate alcohol consumption raises homocystein levels
by 20% which raises chances of coronary heart disease
by 20%. Except for beer which contains folate.
“We postulate that elevated levels of homocysteine in social
drinkers with regular moderate alcohol intake are at risk of
developing cardiovascular diseases, which contradicts the
cardioprotection of alcohol according to the “French Paradox”.”
Bleich S, et al. Alcohol and Alcoholism 2001;36:189-92.
My personal comment: homocyteine levels rise when not
taking in folate i.e. whole grains, fruits, and vegetables. Wine
contains antioxidants, so as long as you are eating a healthy diet
red wine can contribute to health. Otherwise it will not.
Women’s nutrient needs:
Increasing vitamin C intake by 10 (to 1000 mg)
increases IRON absorption by 10.
Hallberg L, et al. Ann N Y Acad Sci 1987;498:324-32.
sources of vit. C: broccoli, lettuce, onions, tomatoes,
apples, cantaloupe, citrus, pineapples, strawberries
sources of iron: whole grains, fruits, vegetables, nuts
For healthy bones:
1. weight-bearing exercise
2. 1200-1500 mg calcium / day (3 glasses of milk)
3. vitamin D helps calcium absorption (also in milk)
Dairy has more calcium and is more absorbable than any other food.
If you don’t like dairy this is a rare instance to use supplements.
Conclusions:
What you DO eat is as important as what you do NOT eat.
EAT: minimally (“appropriately”) processed foods.
moderate amounts of all food types (fat, protein, carbohydrates).
DRINK: water (electrolytes only when exercising or in high heat).
AVOID: processed foods (refined carbohydrates, hydrogenated oils).
substituting carbonated beverages for water.
Even diet soda may cause dehydration if contains caffeine.
Soda, ice cream, and doughnuts have a place in your diet if you want
them. They are for enjoyment. Eat a solid meal or drink water FIRST,
THEN enjoy. Otherwise insulin soars and your diet is in control of you.
Performance nutrition is a matter of being healthy.
This includes performance in thinking, daily activities, as well
as athletics.
To lose body fat minimize processed foods.
Including exercise more than doubles the effectiveness of this.
To lose overall weight requires slight caloric deficit.
Exercise and non-processed foods maximizes fat loss.
Cutting calories simply lowers metabolism (not good).
To gain weight requires slight caloric excess.
Exercise and non-processed foods minimizes fat gain.
Simply eating more of the standard US diet will cause fat gains.
Refined foods are more easily digested and, during exercise,
adrenaline reduces insulin release. Therefore, refined foods are
preferred during exercise.