Optimal Nutrition and Food Choices

Optimal Nutrition

• An optimal diet provides the required nutrients for tissue maintenance, repair, and growth.
• It is important to consume required nutrients without excess kilocalories.
• Proper nutrition enhances physical activity by improving performance, optimizing conditioning, enhancing recovery, and minimizing musculoskeletal injuries.

Food Options

• Liquid meals have high carbohydrate content and supply fluids while digesting rapidly
• Liquid meals are ideal for day-long events and supplement total intake for those maintaining body weight.
• Nutrition bars typically contain around 25g of carbohydrates and high protein content.
• Nutrition bars often include vitamins, minerals, and supplements, but should not substitute normal food intake.
• Powders and drinks generally have high protein content and contain vitamins, minerals, and supplements.
• Powders and drinks often come in powdered form or premixed for convenience.
• Powders and drinks usually contain fewer kilocalories per serving than nutrition bars.

Endurance Exercise Pre-competition Meal

• Three factors influence pre-competition nutrition including food preferences and dietary restrictions, psychological state, and food digestibility.
• This is impacted by GI disease or allergies in the athlete.
• Psychological state contributes in the form of stress and/or anxiety.
• Objective is to maximize muscle and liver glycogen stores.

Pre-competition Meal

• Meals should consist of mostly carbohydrate-rich foods as the majority of the meal.
• Consume 150-300g of carbohydrates (2-5 g/kg of body mass) in either solid or liquid form.
• It is important to consume meals 3-4 hours before competition and contain little lipid and fiber.
• The functions of these is to fill glycogen stores, have carbohydrates in the gut for absorption and release during exercise, prevent hunger during exercise, and stick with familiar foods.

Consuming the Right Carbohydrates

• Consumption before physical activity of concentrated high-glycemic carbohydrates leads to rapid blood sugar increases
• This can trigger an excessive insulin release called an insulinemic response
• Three factors negatively impact endurance.
• Rebound hypoglycemia can be caused by sugar crash.
• Depressed lipid catabolism.
• Premature depletion of glycogen reserves.

Carbohydrate Feedings Before Intense Physical Activity

• High-glycemic carbohydrates should be avoided within 1 hour of physical activity because it negatively impacts performance.
• It induces an insulin overshoot, facilitates glucose influx through muscle, and inhibits lipolysis
• Allow at least 1 hour before competition to eat or drink anything, but if you can't, make sure to properly and thoroughly warm-up.
• Co-ingestion of glucose and fructose can be ideal and have the best absorption rates
• High-fructose beverages absorb slower and have a lower insulin response compared with glucose or sucrose, but can produce GI distress
• High fructose levels may lead to excess eater retention

Modification of Carbohydrate Intake

• Carbohydrate loading is a popular nutritional modification to increase glycogen reserves.
• Combining specific dietary regimens with physical activity produces significant "packing" of muscle glycogen.
• Each 100g of muscle contains 1.7g of glycogen.
• Carbohydrate loading packs contain ≥5g of glycogen per 100g of muscle.

Glycogen Loading Procedure

• For Step 1, prolonged PA for 6 days is recommended before competition.
• For Step 2, maintain a low-carbohydrate diet (60-100 g/day) for 2-3 days to further deplete glycogen stores.
• Glycogen depletion increases glycogen-storing enzyme glycogen synthase in muscle fiber.
• For Step 3, switch to a high-carbohydrate diet (400-700 g/day) 3 days before competing and maintain until the pre-event meal.

Disadvantages of Carbohydrate Loading

• Carbohydrate loading only benefits intense physical activity for 60 minutes or more.
• This can cause the person to feel "heavy"
• It results in addition of 2.7g of water for each gram of stored glycogen.
• The extra weight effect negates any potential benefits from increased glycogen.

Modified 6-Day Loading Procedure

• A modified 6-day protocol reduces some negative effects from previously established procedures.
• It doesn't require prior physical activity to exhaustion but PA at 75% VO2 max for 1.5 hours, then on successive days reduce or taper PA.
• During the first 3 days, carbohydrate supply is ~50% of total kcals.
• For 3 days before competition, increase carbohydrates to 70% of total kcal intake.

Modified 1-Day Loading Procedure

• One bout of exhausting PA is recommended, followed by high Glycemic Index carbohydrates.
• 150 seconds are performed @ 130% VO2 max with one 30 second burst all-out.
• Carbohydrate levels increase ↑ 82% in all fiber types of vastus lateralis muscle after only 24 hours.
• This is similar to 2-6-day interventions.

Carbohydrate Feedings During Intense Physical Activity

• Greater intensity is allowed during prolonged physical activity.
• Each hour, a 30-60g liquid or solid carbohydrate serving benefits high-intensity, long-duration aerobic PA and repetitive short bouts of near-maximal effort.
• Carbohydrates spare muscle glycogen.
• Carbohydrates help regulate optimal blood glucose levels.

Carbohydrate Feedings During Intense Physical Activity

• Consuming carbohydrates during physical activity (60-80% aerobic capacity) can postpone fatigue.
• May help improve performance.
• Consuming carbohydrates early in exercise will ensure it is available during later parts of exercise.

Carbohydrate + Protein Feedings During Intense PA

• Adding protein reduces muscle damage and helps with glycogen resynthesis
• This increases the glycogen storage

Carbohydrate Feedings Following Physical Activity

• Consume high-glycemic, carbohydrate-rich foods quickly to speed glycogen replenishment.
• Muscle glycogen restoration is faster and more complete when carbohydrate consumption occurs during the first 30 minutes post-exercise as opposed to delaying carbohydrate consumption for 2 hours.
• When completing a glycogen-depleting bout of activity: consume 0.6-1.0g of carbohydrate/kg of body weight within 30 minutes and every 2 hours for the next 4-6 hours.
• You may take up to 1.5g/kg.
• Consume 1.0-1.2g of carbohydrate/kg of body weight every 30 minutes over a 3.5 hour period.
• Include protein at ½ per kg BW

Carbohydrate + Protein Feedings Following Physical Activity

• May be most beneficial for glycogen storage when carbohydrate intake is <1.2g/kg.
• Some data shows that consuming Carbohydrates and proteins within the 2 hour post-exercise window may help performance the following day.
• May enhance insulin secretion compared to Carbohydrates alone.
• Greater insulin release equals greater protein synthesis and glucose uptake and increased glycogen replenishment.

Optimizing Glycogen Replenishment

• There are two methods to optimize replenishment.
• One is gorging on a single meal, which results in a greater incremental glucose and insulin response.
• Two is nibbling on frequent, smaller snacks, which produces a more stable glucose and insulin response.

Consuming Right Form of Carbohydrates

• Optimal glycogen replenishment benefits those involved in regular intense training.
• Optimal glycogen replenishment benefits those involved in tournament competitions with qualifying rounds.
• Optimal glycogen replenishment benefits those involved in competitive events scheduled with only 1 or 2 recuperation days.

High-Fat versus Low-Fat Diets for Endurance

• Proponents of high-fat diets argue a long-term increase in dietary lipids accomplishes three goals:
• Stimulates lipid burning by augmenting capacity to mobilize and catabolize lipid.
• Conserves glycogen reserves.
• Contributes to improved endurance under low-glycogen conditions. Reliable research has not demonstrated consistent endurance benefits from a high-fat diet.

Nutrition Preceding Resistance Exercise

• Resistance exercise reduces muscle glycogen stores, but this is modest compared to aerobic exercise.
• Could deplete glycogen stores 24-40%, depending on duration and intensity.
• Pre-exercise carbohydrate consumption may improve performance in subsequent sessions.
• Protein ingestion pre- vs. post-exercise may produce similar results in muscular adaptation and muscle protein synthesis.
• So, as long as you get the nutrients, timing may not be as much of an issue here.

Nutrition During Resistance Exercise

• Carbohydrate consumption during resistance exercise may attenuate glycogen depletion from the session.

Nutrition Following Resistance Exercise

• If protein wasn't consumed pre- or during exercise, consume it post-exercise.
• Carbohydrates can also be consumed in order to restore glycogen.
• Timing is especially important if there is more than 1 training session (or competition event) per day!
• Most important factor for protein intake is timing, not amount.
• 15-20g (~0.25-0.30g/kg) should be consumed 1 hour before or after.
• Most important factor in muscle building is caloric intake.
• 1lb muscle mass equals 350-500 additional daily kcals.

Timing Meals Throughout the Day

• Focus on ideal vs. realistic opportunities as you plan your schedule.
• Balance your daily schedule, work/school, training schedule, and dietary preferences while focusing on the 4 R's of sport nutrition.
• Eating 20–40 g PRO dose (0.25–0.40 g/kg body mass/dose) of a high-quality source every 3-4 hours appears to most favorably affect Muscle Protein Synthesis.
• It also associates with improved body composition and performance outcomes.
• Consuming casein protein at around 30–40 g prior to sleep can acutely increase Muscle Protein Synthesis and metabolic rate throughout the night.

Post-Exercise Recovery

• It is recommended that athletes always remember the 4 R's of Sport Nutrition
• Rehydrate.
• Replenish glycogen.
• Repair muscle.
• Rest (sleep).