sport nutrition (exphys)

What is body composition?

The proportion of fat mass and fat-free mass in the body.

What are the two main components of body composition?

Fat mass and fat-free mass.

What percentage of North American adults are overweight?

Over 70%.

What is positive energy balance?

When energy intake is greater than energy expended, resulting in weight gain.

What is negative energy balance?

When energy intake is less than energy expended, resulting in weight loss.

How many calories are approximately equivalent to 1 lb. of weight loss?

Approximately 3500 kcal.

What is hydrostatic weighing?

A method of measuring body density by underwater weighing.

What is DEXA?

Dual-energy X-ray absorptiometry, a precise method for quantifying bone and soft-tissue composition.

What does air plethysmography measure?

Body composition using air displacement instead of water.

What is the skinfold method?

A field technique that measures the thickness of skinfolds at multiple sites to estimate body fat.

How does bioelectric impedance work?

It measures body composition by passing a current through the body and assessing resistance based on fat-free mass and fat mass.

Why is fat-free mass important for athletes?

It contributes to power, strength, and muscle endurance.

What is the relationship between relative body fat and athletic performance?

Less fat usually correlates with better performance, except in certain sports like sumo wrestling and weightlifting.

What are Westernized dietary patterns characterized by?

High levels of saturated fats, sugars, and sodium.

What health problems are associated with excess body fatness?

Increased likelihood of various health issues.

What is a signal for evaluating diet and lifestyle?

A weight gain of greater than 10 pounds.

What are the limitations of hydrostatic weighing?

Confounding factors like lung air volume and variability in fat-free density among individuals.

What is the main advantage of DEXA?

It provides precise and reliable measurements of body composition.

What is a potential drawback of air plethysmography?

It can be difficult for the operator and is expensive.

What is the most widely used field technique for assessing body composition?

Skinfold measurement.

What is the significance of fat as a body composition component?

It acts as a dead weight but is also a useful energy store.

What is a common misconception about weight loss in sports?

The misconception is that if small weight loss is good, then large weight loss is better.

What are the risks associated with severe weight loss in athletes?

Risks include dehydration, chronic fatigue, menstrual dysfunction, and disordered nutrition.

What is the female athlete triad?

The female athlete triad consists of eating disorders, menstrual dysfunction, and bone disorders.

What are potential health consequences of Relative Energy Deficiency in Sport (RED-S)?

Potential health consequences include impaired performance, chronic fatigue, and increased risk of injury.

What is the recommended approach to achieving optimal weight for athletes?

The approach includes moderate caloric restriction combined with exercise, aiming for a caloric deficit of 200 to 500 kcal/day.

What is the recommended macronutrient balance for athletes?

Carbohydrates should comprise 55% to 60%, fat less than 35%, and protein 10% to 15% of daily kilocalories.

What is the role of carbohydrates in an athlete's diet?

Carbohydrates serve as the primary energy source and regulate fat and protein metabolism.

What is the significance of glycogen in athletic performance?

Glycogen is crucial for energy during exercise and its stores are determined by dietary carbohydrate intake.

What is the glycemic index (GI)?

The glycemic index categorizes foods based on their blood sugar response.

What is the difference between high-GI and low-GI foods?

High-GI foods (GI > 70) cause a rapid increase in blood sugar, while low-GI foods (GI ≤ 55) result in a slower, more gradual increase.

What are the effects of carbohydrate intake during exercise?

Carbohydrate intake during exercise can improve performance and prevent hypoglycemia.

What is the recommended protein intake for athletes?

Athletes should consume 1.2 to 1.7 g of protein per kg of body weight per day.

What is the impact of excessive protein intake?

Excessive protein intake can lead to health risks.

What is the importance of post-exercise carbohydrate and protein consumption?

Consuming carbohydrates and protein after exercise promotes recovery and enhances glycogen and muscle protein synthesis.

What are essential and nonessential amino acids?

Essential amino acids cannot be produced by the body and must be obtained from food, while nonessential amino acids can be synthesized by the body.

What is the recommended dietary allowance (RDA)?

The RDA is an outdated standard for estimating safe, adequate dietary intakes and minimum vitamin and mineral requirements.

What is the current standard for dietary intake called?

The current standard is called the Daily Recommended Intake (DRI).

What is the role of fats in the body?

Fats are essential for body function, serving as a fuel substrate and being components of cell membranes and nerve fibers.

What is the recommended limit for saturated fat intake?

Saturated fat intake should be less than 10% of total daily kilocalories.

What are the consequences of low caloric intake in athletes?

Low caloric intake can lead to delayed menarche, oligomenorrhea, or amenorrhea, particularly in low-body-weight sports.

What is the relationship between caloric intake and athletic performance?

Caloric intake must meet or exceed caloric expenditure to maintain health and performance.

What is the significance of bone mineral loss in female athletes?

Bone mineral loss is a serious consequence of athletic amenorrhea, increasing fracture risk.

What is the impact of fasting and crash diets on athletes?

Fasting and crash diets can lead to more water and muscle loss rather than fat loss.

What is the recommended caloric deficit for optimal weight loss in athletes?

A caloric deficit of 200 to 500 kcal/day is recommended for optimal weight loss.

What are vitamins?

Small but essential organic molecules that enable the use of other ingested nutrients and act as catalysts and cofactors in chemical reactions.

What is the difference between fat-soluble and water-soluble vitamins?

Fat-soluble vitamins can be stored and may accumulate to toxic levels, while water-soluble vitamins are excreted and toxicity is difficult to reach.

Are vitamin supplements helpful if there is no deficiency?

Generally, supplementation is not helpful unless a vitamin deficiency exists.

What are B-complex vitamins essential for?

They are essential for cellular metabolism and ATP production, including the conversion of pyruvate to acetyl-CoA and the formation of FAD and NADH.

What is the role of Vitamin C?

Important for collagen maintenance, acts as an antioxidant, and is involved in adrenal hormone synthesis and iron absorption.

What is Vitamin E known for?

It is stored in muscle and fat and is a potent antioxidant.

What are minerals?

Inorganic substances needed for cellular function, classified into macrominerals and microminerals (trace elements).

What is the function of calcium in the body?

It is important for bone density, nerve function, and muscle function; concerns include osteopenia and osteoporosis.

What is phosphorus's role in the body?

It is bound to calcium in bones and is important for metabolism, cell membranes, buffers, and bioenergetics.

What is the significance of iron?

Critical for hemoglobin and myoglobin for oxygen transport; deficiency can lead to anemia, while excess can cause toxicity.

What electrolytes are primarily found in interstitial fluid?

Sodium (Na+) and chloride (Cl-).

What is the average water content of fat-free mass?

73% water.

What percentage of body water is intracellular and extracellular?

2/3 of body water is intracellular, and 1/3 is extracellular.

What are the common causes of dehydration during exercise?

Increased sweat loss due to higher body temperature and water loss exceeding water gain.

What factors influence body temperature and sweating?

Environmental temperature, radiant heat load, humidity, air velocity, body size, and metabolic rate.

What is hyponatremia?

A condition where serum sodium levels fall below 135 mmol/L, often due to excessive sodium loss and rehydration.

What are mild symptoms of hyponatremia?

Bloating, puffiness, nausea, vomiting, and headache.

What is the recommended fluid intake before competition?

400-600 ml at least 2 hours before competition.

What is carbohydrate loading?

A strategy to maximize glycogen stores by tapering training and increasing carbohydrate intake before an event.

What is the composition of sports drinks?

Water, energy (carbohydrates), and electrolytes, providing performance benefits.

What is the typical carbohydrate concentration in sports drinks?

Most drinks contain 6 to 8 g of carbohydrates per 100 ml of fluid.

How does sodium concentration in sports drinks aid rehydration?

Sodium enhances water absorption and promotes thirst, which aids in rehydration.

What is the effect of dehydration on aerobic performance?

Increased temperature leads to increased sweat loss, reducing performance and cardiovascular function.

What is the relationship between carbohydrate intake and muscle glycogen resynthesis post-competition?

Carbohydrate and protein intake within 2 hours after competition can enhance muscle glycogen resynthesis.