sports nutrition – eat to compete
DESCRIPTION
Sports Nutrition – Eat to Compete. Mark Mirabelli, M.D. Assistant Professor Depts. of Orthopaedics and Family Medicine University of Rochester. Goals. Understand basics of general nutrition Recommendations for pregame and postgame meals Brief words on sports supplements. - PowerPoint PPT PresentationTRANSCRIPT
Sports Nutrition – Eat to Compete
Mark Mirabelli, M.D.Assistant Professor
Depts. of Orthopaedics and Family Medicine
University of Rochester
GoalsUnderstand basics of general nutritionRecommendations for pregame and
postgame mealsBrief words on sports supplements
Key Nutrition and Performance Goals
Optimize/maintain hydration/ electrolyte status Maximize/maintain fuel supplies Maximize protein synthesis to increase lean body mass Accelerate recovery from a strenuous bout of activity
Carbohydrates ENERGY Protein Growth, Repair Fat Energy stores Water Fluid balance
Vitamins Body Processes Minerals Body Processes
Nutrient Function
•4 calories for each gram•Provides ENERGY for athletes!•50%-60% of our total diet
•Simple carbs for fast energy• Candy, Soda, Fruit, Sugary foods
- Complex for sustained energy• Pasta, Rice, Breads, Grains, Starchy foods
Carbohydrates
Maximize Glycogen Synthesis Glycogen - primary fuel source during moderate to high intensity exercise Muscle glycogen repletion is slow, and can take 24 hrs. Exponential relation between rate of glycogen resynthesis and recovery time Restoration of muscle glycogen most critical factor for recovery/ subsequent performance
Glycogen and Resistance Training: Resistance exercise reduces glycogen by approximately 30-40%;
Resynthesis is slow unless energy substrates are provided; Provision of CHO after exercise enhances resynthesis of glycogen; Provision of protein and fat with CHO after exercise does not impair resynthesis.
Comparison of Diets Low CHO diet (40% kcal from CHO)•Double cheeseburger•Medium fries•Chocolate milkshake
High CHO diet (70% kcal from CHO)•12 inch sub sandwich (lots of vegetables & no mayo)
•500 ml apple juice•250 ml chocolate milk
•banana
Carbohydrate Snacks Foods supplying 50g CHO•500 ml Juice•3 Medium pieces of fruit•1 honey sandwich•2 breakfast bars•1 sports bar (check label)•1.3 bagels•1/2 cup dried fruit•1 cup white rice•1 baked potato
Critical Re-Fueling Interval
Recovery Recovery
Exe
rcis
e
Exe
rcis
e
Re-FuelingInterval
Re-FuelingInterval
Phases of Timing Nutrient Intake
Summary To replete glycogen stores after exercise, carbohydrates should be eaten within 15 min and repeated every 2 hr for 4 to 6 hr.
Ingesting protein following resistance exercise should enhance protein synthesis and may inhibit protein catabolism.
For recovery from exercise, food with a CHO to protein ratio of about 4 to 1 should be ingested within 30 minutes after exercise.
•4 calories for each gram•Growth and Repair of all tissue (muscle etc)•10%-15% of our total diet•Red meat, chicken, pork, Fish, Eggs
Protein
150 LBS 10% body fat 90% lean body
150 LBS 35% body fat 65% lean body
Who needs more protein?
•9 calories for each gram (more than double carbs and protein)
•Padding, protection, hormonal response•25%-30% of our diet
• TWO TYPES:• Unsaturated (15%-20%) GOOD fat (plant)
– -Liquid at room temperature– Oils, Nuts, Seeds, Avocados etc.
• Saturated (10%) BAD fat (animal)– -Solid at room temperature– Red meats, fried foods, butter
Good Fat = Plant based Oils
Nuts are healthy
Olive Oils
Nutrient dense
Hydration Status and Guidelines
Regulation of Water Balance Thirst•Daily water balance varies between 0.2 and 0.5% each day, independent of climate
Metabolism•Daily turnover between 3.3 and 4.5 L/day (6 L for very active populations) for sedentary and active populations
Requirements•Low activity: 4.5 - 8 L/day•High Activity: 6 to 12 L/day
Losses•1 - 2 L/h for athletes
Dehydration and
Performance
Dehydration and Performance
Impaired temperature regulation
Reduced muscular
endurance
Reduced strengthReduced
endurance capacity
Heat cramps
Severe heat cramps
Heat strokeComaDeath
We
igh
t L
os
s (
% B
od
y W
eig
ht)
8
6
4
2
Urine color test for dehydration
Lemonade—The good
Apple juice—The bad
Tea—The ugly
Monitoring HydrationStatus
1
2
3
4
5
6
7
8
9
Fluid recommendationsClear liquids up to 1 hour before event
Drink 3-8 fl oz of water every 15-20 min when exercising for < 60 min
Drink 3-8 fl oz of a beverage with CHO (5% to 8%) and electrolytes every 15-20 min when exercising> 60 min.
Simple liquid carbs after event
DO NOT DRINK MORE THAN 1 L or 1 Qt/hr during exercise.
MineralsMineralsNecessary for food metabolism, energy production, and protection of body tissues
Iron and Zinc supplementation beneficial in those with deficiency
Sparse evidence– Magnesium, Copper, Selenium, Chromium
VitaminsVitamins Required nutrients in
the diet (A,B,C,D,E,K) Traditionally no need to
supplement dietary intake
No advantage to ingesting “mega” doses
Can be necessary in restrictive type diets to replace lost intake
USDA My Plate
Selected Messages for ConsumersBalancing CaloriesEnjoy your food, but eat less.Avoid oversized portions.
Foods to IncreaseMake half your plate fruits and vegetables.Switch to fat-free or low-fat (1%) milkMake half your grains whole grains.
Foods to ReduceCompare sodium in foods like soup, bread and frozen meals and choose the foods with lower numbers.Drink water instead of sugary drinks.
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Balancing calories
Enjoy your food, but eat less
Avoid oversized portions
Nutrient Dense and Non-Nutrient Dense Forms of Sample Foods
What A Typical M.S./H.S. Athlete Eats Prior to Activity:
Breakfast: 0 calories Lunch: 450-550 calories•Chips = 100 calories •1 slice of Pizza = 200-250 calories•Gatorade or other drink = 150-200 calories
Total: 450-550 Calories Prior to Activity!
Caloric Need For Practice or Game
•Football: 900-2700 •Basketball: 600-1800•Running: up to 1500 •Wrestling: up to 1800 •Baseball: 450-1200 •Dance/Cheerleading: 450-1000
•TV or Reading: up to 270
ARE THOSE 500 CALORIES GETTING THE JOB DONE?
It takes 1- 4 hours for food to leave your stomach
High Carb foods are digested quickly
High Protein foods can increase water requirements
Foods high in Fat can stay in your stomach for more than 4 hours
Best choice for pre-game meals is something high in Carbs - easy to digest
and becomes quick energy !
The Pregame Meal
Pre-Event Meal Goals “Top off” glycogen stores Optimize hydration
Empty upper GI tract
Pre-Event Meal Meal Composition High in carbohydrates•mixed complex and simple
Reasonably low in fats and protein Low in dietary fiber
Pre-Event Meal Composition (cont.) High in fluids Individualize •Use familiar foods
Pre-Event Meal Timing of meal•Complete > 2 hours before event
Individualize (3-4 hours better for some)
1994 Dietary Supplement Health and Education Act 1994 Dietary Supplement Health and Education Act (DSHEA)(DSHEA)
• Intent: allow consumers access to nutrition based supplement
• FDA no longer responsible for the purity or safety of dietary supplements
• responsible for taking action against UNSAFE dietary supplements after market
• Supplement manufacturer is responsible safety, efficacy but do not have to provide EVIDENCE
• No approval or product registration required
• FTC responsible for regulating advertising claims/labeling
• Can make health, nutrient, or structure/function claim NOT disease claim
Lack of Regulation and EvidenceLack of Regulation and Evidence
Few well designed studies exist
Most studies showing benefits of supplements are biased (funded by manufacturer)
Few patients actually studied Placebo effect (sugar pill) may account for up to 30-50% of the benefit of supplements
Supplements Conclusions
•Some supplements improve performance somewhat in some athletes some of the time
•Supplement use is ubiquitous•Theory is better than reality - many claims of supplements to improve sports performance are untrue, overstated or taken out of context
•There are few or no studies of most supplements in athletes
For More Information
Web resources:•www.usada.org•www.wada-ama.org•www.drugfreesport.com•www.choosemyplate.gov