Exs 323: Ch 18 Nutrition & Body composition pt1&2

Lecture Outline

• Why discuss nutrition and body composition?

• Body Composition

• Standards of Nutrition

• Classes of Nutrients

• Dietary Guidelines for Americans

• Obesity and Weight Control

• Diet, Physical Activity, and Weight Control

Body Composition

• Body Composition: Refers to the proportions of fat, bone, water, and muscle in the body. It is typically reduced to lean mass, mineral mass, body water, and fat mass.

• Understanding body composition is crucial for achieving optimal athletic performance and maintaining overall health and well-being, as it provides insights into an individual's metabolic and physiological state.

Why Discuss Body Composition

• Body composition is a vital component of health-related fitness. It complements other fitness metrics such as:

  • Cardiorespiratory fitness: The ability of the circulatory and respiratory systems to supply oxygen during sustained physical activity.

  • Flexibility: The range of motion around a joint.

  • Muscular strength: The maximum amount of force exerted by a muscle or group of muscles.

  • Muscular endurance: The ability of a muscle to sustain repeated contractions against resistance for an extended period.

  • Body Composition: Quantifies and characterizes the components that make up an individual's physique.

• The physiology and adaptations to exercise play a significant role in influencing health outcomes. Understanding the body's responses to various forms of training (Aerobic, Anaerobic, and Resistance Training) helps tailor fitness programs effectively.

Measures of Body Leanness or Fatness

• BMI (Body Mass Index): A simple calculation comparing a person's height and weight. While BMI is highly correlated with body composition, it does not measure body composition directly and can misclassify individuals, particularly those with high muscle mass.

• Percent body fat: Indicates the proportion of fat within the body and is more associated with health risks such as cardiovascular disease and metabolic syndrome than BMI alone.

Body Composition and Health: Obesity and Weight Control

• Excessive body fatness is linked to numerous chronic diseases, which include but are not limited to:

  • Hypertension: High blood pressure that can lead to heart disease.

  • Type 2 diabetes: A chronic condition affecting the way the body processes blood sugar.

  • Cardiovascular Disease/Stroke: Cardiovascular disease and strokes are linked to high levels of body fat.

  • Gallbladder disease: Increased risk of conditions affecting the gallbladder, including gallstones.

  • Osteoarthritis: Joint pain and deterioration linked to excess weight.

  • Sleep apnea and respiratory problems: Breathing interruptions during sleep that are more common in overweight individuals.

  • Certain cancers: Including endometrial, breast, prostate, and colon cancer have been associated with higher body fat percentages.

• The prevalence of obesity contributes significantly to chronic disease risk, and global obesity rates are continuing to rise, driven by a combination of lifestyle, environmental, and genetic factors.

Obesity Trends

• The trends of obesity among U.S. adults have been tracked using the BRFSS (Behavioral Risk Factor Surveillance System) from 1985 to 2023.

• A BMI of ≥30 is classified as obese, which roughly corresponds to being at least 30 lbs overweight for a person standing 5' 4" tall. This threshold is important for understanding societal health challenges.

• Data over the years shows a gradual increase in obesity prevalence across various demographics, indicating a societal health crisis.

Obesity Prevalence

• Currently, approximately 33.6% of U.S. adults are classified as obese (BMI ≥30lbs).

• Additionally, around 67.7% of U.S. adults are either overweight (BMI ≥25) or obese, highlighting a significant public health issue.

• Higher obesity rates are observed in certain groups based on ethnicity and socioeconomic status, with disparities seen (Black > Hispanic > White >> Asian).

• Obesity is recognized as a growing global concern, affecting millions worldwide and demanding effective intervention strategies.

Causes of Obesity

• The causes of obesity are multifaceted and cannot be attributed to a single factor; a combination of genetic, cultural, social, and lifestyle factors contribute to its prevalence:

  • Genetic factors: Research suggests that genetic inheritance accounts for around 25% of the variability in fat mass and body fat percentage.

  • Cultural factors: Environmental influences and societal norms may account for around 30% in the prevalence of obesity.

  • Energy balance: Fundamental changes in body mass are driven by the balance between energy intake and energy expenditure, highlighting the significance of lifestyle choices in weight management strategies.

Sugar Consumption and Obesity

• A graphical representation correlating sugar consumption per capita with obesity rates illustrates the importance of dietary choices in addressing obesity's rise.

Correlation and Causation

• It is essential to understand that correlation does not imply causation; various humorous and anecdotal examples illustrate this misunderstanding, such as correlations seen between Internet Explorer market share and murder rates, or ice cream sales and shark attacks.

Take Home Messages

• Understanding body composition is critical for overall health and fitness assessments.

• The rise in obesity is linked to various chronic diseases, highlighting the importance of addressing dietary habits as well as physical activity.

• The complexity of obesity's causes and its rising prevalence necessitates a comprehensive approach to prevention and management.

Methods of Assessing Overweight and Obesity

• Body Mass Index (BMI) formula: Mass (kg) / Height (m^2) is a straightforward metric for assessing body weight in relation to height.

  • Classification for adults:

  • Underweight: BMI < 18.5 kg/m^2

  • Normal: BMI 18.5–24.9 kg/m^2

  • Overweight: BMI 25.0–29.9 kg/m^2

  • Obesity: BMI ≥ 30.0 kg/m^2

  • Classification for children:

  • Overweight: BMI ≥ 85th percentile for age and gender

  • Obese: BMI ≥ 95th percentile for age and gender

• While BMI is widely used, it alone does not provide comprehensive insights into body composition, potentially misclassifying athletes or muscular individuals.

BMI and Anthropometrics

• BMI correlates well with overall body composition, with NHANES data indicating about 80% accuracy in BMI predictions of excess adiposity; however, some individuals may be misclassified (e.g., 'skinny fat').

• BMI should not be treated as a solitary risk factor and must be interpreted with caution, considering individual differences.

• The distribution of body fat is significant, as abdominal obesity is linked to higher cardiovascular disease risk. Important metrics include:

  • Waist circumference > 102 cm (men) and > 88 cm (women).

  • Waist-to-hip ratio > 0.95 (men) and > 0.80 (women).

Body Fatness for Health and Fitness

• Health standards recommend percent body fatness to be:

  • Generally: 10-25% for men, 20-35% for women

  • Fitness Standards: 5-15% for men, 15-25% for women

Measuring Body Composition

• Various methods exist for body composition measurement, including:

  • Laboratory-type measures (less common)

  • Indirect testing

  • Doubly indirect testing (indirect-indirect)

Some techniques provide greater precision (e.g., DEXA), while others are more suited for field use (e.g., skinfold measurements or bioelectrical impedance analysis).

Laboratory Measurements

• Laboratory techniques allow for more direct body composition assessments, including:

  • Dissection (cadavers only)

  • Isotope dilution (consuming deuterated or tritiated water)

  • Photon absorptiometry (measuring tissue density)

  • Potassium-40 measurement ( ext{}^{40}K concentration related to lean mass)

  • Radiography or ultrasound for regional tissue measurements

  • Nuclear magnetic resonance (NMR) or Total body electrical conductivity (TOBEC) to assess body response in an electromagnetic field

Indirect Measurements of Body Composition

• Common indirect methods (like underwater weighing and air displacement plethysmography) measure body density (D_b) and then calculate percent body fat based on:

  • Fat mass: Adipose tissues (both visceral and subcutaneous)

  • Fat-free mass: Comprises everything except fat (bone, muscle, blood, etc.)

Two-Component System of Body Composition

• The body is categorized into fat-free mass and fat mass:

  • Fat mass is estimated based on lipid density (Density = 0.900)

  • Fat-free mass (Density = 1.100)

• Equations used to calculate density, leading to body fat percentage calculations include:

  • ext{% body fat} = rac{495}{Density} – 450

  • ext{% body fat} = rac{457}{Density} – 414.2

• Whole-body density (D_b) can be measured using underwater weighing or air displacement plethysmography.

• Skinfold thickness measurements are also used to estimate body density.

• An equation converting body density to percent fat can vary depending on factors such as age, gender, and ethnicity, with models like the Siri and Brozek equations commonly used.

Take Home Messages

• BMI employs a basic weight-to-height ratio (kg/m^2) to classify individuals, with the following ranges: healthy (18.5-25), overweight (25-30), and obese (≥30).

• BMI does not consider the composition of weight (muscle vs. fat); therefore, diverse techniques exist for accurate body composition measurement.

• Acceptable body fatness ranges: Males: 5-25%; Females: 15-35%; fitness ranges may be as low as 5-15% in males and 10-25% in females.

• BMI is a useful tool that correlates with body composition but doesn't directly measure it.

• Body composition can be assessed via:

  • Hydrostatic weighing

  • Dual-Energy X-Ray Absorptiometry

  • Air-displacement Plethysmography

  • Bioelectrical Impedance Analysis

  • Skin-fold thickness

• Excess body fat is associated with certain chronic diseases.

• BMI ranges:

  • Underweight: <18.5

  • Healthy: 18.5-24.9

  • Overweight: 25-29.9

  • Obese: >30

• Body composition ranges:

  • Males: 5-25%

  • Females: 15-35%

Body Weight Management

• Genetics and culture influence body mass.

• Physical activity and nutrition are critical for altering body mass/composition.

• Nutrition accounts for new energy (carbon) entering the body and provides building blocks.

• Physical activity expends energy (carbon) and modifies body composition to maintain metabolic rate.

• Obesity is a public health concern due to its association with chronic diseases.

Nutrition - Big Picture

• Nutrition is the study of food and nutrients, including their digestion, absorption, metabolism, and effect on health and disease.

• Nutrients are substances in food that provide nourishment to support body function and maintain health.

• Nutrients serve three primary purposes:

  • Provide energy

  • Support growth and development

  • Regulate metabolism

• Poor diet increases the risk of health problems like Cardiovascular disease, diabetes, cancer, and obesity.

  • Estimated that 50% of deaths in the US are related to poor dietary habits.

• Six classes of nutrients:

  • Water

  • Vitamins

  • Minerals

  • Carbohydrates

  • Fats

  • Proteins

Dietary Reference Intakes (DRIs)

• DRIs encompass specific standards for dietary intake.

• DRIs include:

  • Estimated Average Requirement (EAR): The mean/average value observed to meet the requirements of a population.

  • Recommended Daily Allowances (RDA): Quantity of each nutrient to meet the needs of nearly all (97–98%) healthy persons. Calculated as EAR + 2 \times \text{standard deviations}.

  • Adequate Intakes (AI): Nutrient levels assumed adequate when EAR/RDA cannot be determined.

  • Tolerable Upper Intake Level (UL): The highest intake level unlikely to pose a health risk.

Acceptable Macronutrient Distribution Ranges (AMDRs)

• AMDRs are intake ranges for energy sources associated with a lower risk of chronic disease while providing adequate intake of essential nutrients.

• These are percentages of caloric intake, not total mass (g) of the food item.

  • Carbohydrates: 45–65% calories from carbohydrates (CHO provides 4 kcal/g).

  • Fats: 20–35% calories from fat (Fat provides 9 kcal/g).

  • Proteins: 10–35% from protein (Protein provides 4 kcal/g).

DRIs (continued)

• Estimated Energy Requirement (EER):

  • Average dietary energy intake predicted to maintain energy balance.

  • Considers age, gender, weight, height, and level of physical activity.

• Daily Value (DV):

  • Standard used in nutritional labeling.

  • Percentage of recommended intake in each serving.

  • Based on a 2,000 kcal/day diet, not an EER for a specific individual.

Take Home Messages (Nutrition)

• Nutrition studies food and nutrients, including their digestion, absorption, metabolism, and effect on health and disease.

• DRI is an umbrella term that defines specific standards for dietary intake:

  • RDA

  • AI

  • UL

  • ADMR

  • EER

  • Daily value

• Current AMDR recommendations for the distribution of calories include:

  • Carbohydrates: 45% to 65%

  • Fats: 20% to 35%

  • Proteins: 10% to 35%

Six Classes of Nutrients

• Macronutrients: Nutrients required in relatively large amounts (more than a few grams per day).

  • Water

  • Fat

  • Proteins

  • Carbohydrates

• Micronutrients: Nutrients required in relatively small amounts (less than 1 gram per day).

  • Vitamins: Essential organic substances required in the diet for normal function, growth, and maintenance of body tissues.

  • Minerals: Chemical elements required for normal function.

    • Major minerals: Required in higher amounts.

    • Trace minerals: Required in very small quantities.

Carbohydrates

• Sugars and starches

  • Contain 4 kcal/g

  • Major energy source

  • Crucial for red blood cells and neurons

  • RDA: 130g/day based on CNS requirements

• USDA DG Recommendations:

  • Choose or prepare foods and beverages with little added sugars or caloric sweeteners.

  • Reduce the incidence of dental caries by consuming sugar-containing foods and beverages less frequently.

Carbohydrates (cont.)

• Dietary fiber:

  • Non-digestible carbohydrates and lignin

  • Reduces transit time in intestine

  • Soluble fiber linked to lower serum cholesterol

• Functional fiber:

  • Non-digestible carbohydrates

  • Have beneficial physiological functions

• USDA DG Recommendations

  • AI: 38 g/day for men, 25 g/day for women

  • Increase dietary fiber and complex carbohydrate intake

  • Decrease simple sugar intake

Fats

• Important energy source: Contain 9 kcals/gram

  • Triglycerides

  • Phospholipids

  • Cholesterol

• Low-density lipoproteins (LDLs):

  • Directly related to cardiovascular disease risk (CVD)

  • Increased by diets high in saturated fat

• High-density lipoproteins (HDLs):

  • Protect against heart disease

Fats (Dietary Recommendations)

• Consume <10% calories from saturated fats and <300 mg/day cholesterol

• Keep total fat intake between 20–35% calories

• Most fats should come from polyunsaturated and monounsaturated fats

• Choose and prepare meat, poultry, dry beans, milk, and milk products that are leaner, low fat, or fat-free

• Increase seafood intake in place of meat and poultry

• Limit intake of fat and oils high in saturated and/or trans fatty acids

• Replace solid fats with oils

Proteins

• Not a major source of energy: 4 kcals/g

• High-quality proteins contain the nine essential amino acids (cannot be synthesized by the body).

• Most Americans meet protein intake requirements: 0.8 grams/kg body weight

• Requirements may be higher in athletes (1-2g/kg)

• Supplementation is not necessary in most individuals

Limiting Amino Acids: vegetarians/vegans

• The lowest concentration essential amino acid in a food or diet is the “limiting amino acid”.

  • Eg, a food containing all EAA except methionine; then methionine is the limiting amino acid

• How to get around this problem…?

Take Home Messages (Macro Nutrients)

• Carbohydrate is a primary source of energy in the American diet and is divided into two classes: that which can be metabolized (sugars and starches) and dietary fiber

  • Should be 45-65% of calories.

• The current recommendation for fat intake is no more than 35% of total calories. Trans fat intake should be reduced as much as possible.

• The protein requirement for most individuals is 0.8g/kg; this intake can be met with low-fat selections to minimize fat intake.

  • Should be 10-35% of calories

Water

• Absolutely essential for life

  • Universal solvent and required for normal biochemical reactions to occur

  • Loss of only 3–4% body water can affect athletic performance

• Water loss: Normally ~2500 ml per day

  • Temperature and exercise can increase water loss to 6–7 liters per day

• Water intake:

  • Beverages (1500 ml)

  • Solid food (750 ml)

  • Metabolic processes (250 ml)

• Adequate Intake (AI):

  • 2.7 L/day or ~91 fl oz (women)

  • 3.7 L/day or ~125 fl oz (men)

  • 16fl oz glass is ~7.8 glasses of water for men or ~5.7 glasses of water for women

• Simplest ways to monitor hydration status is the color of urine

Vitamins

• Fat-soluble vitamins: A, D, E, K

  • RXR and RAR are common throughout the body and include Vit. D receptors

  • Can be stored in the body

  • Excess intake can be toxic

• Water-soluble vitamins: B vitamins

  • Thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyroxidine (B6), Biotin (B7) folate (B9), and Cobalamin (B12)

  • Involved in energy metabolism

• Vitamin C:

  • Maintenance of bone, cartilage, and connective tissue

• Adequate vitamin intake is required for health

• An RDA exists for most vitamins but where insufficient evidence exists, an AI has been established.

B family of vitamins can be weird…

• Vitamin B4 was first given the compound name Adenine, which was later found to be one of the nucleic acids that make up structural DNA. It can be synthesized by the human body and therefore not a vitamin.

• Vitamin B8 is a nutrient that is known as Inositol. Even though it is often referred to as a vitamin, Inositol doesn’t meet the definition because it can be synthesized in the body.

• Vitamin B10 is the name once given to Pteroylmonoglutamic acid, also known as Vitamin R. Scientists later discovered this compound doesn’t provide the necessary benefits thus was classified as a non-essential nutrient and it lost its vitamin status. Today you will often see Bara-amino benzoic acid or PABA called Vitamin B10. PABA is actually a component of Pteroylmonoglutamic acid and is also referred to as Vitamin Bx.

• Vitamin B11 was the name given to Salicylic acid as well as Factor S. While this compound does play an important role in our health, it can be synthesized in the body and so it doesn’t fall under the definition of an essential vitamin. Pteryl-hepta-glutamic acid is also sometimes listed as Vitamin B11, but it turns out this is actually a form of Folic acid (Vitamin B9).

• Vitamin B13 is Orotic acid, it is sometimes used as a mineral carrier in some dietary supplements (to increase their bioavailability), most commonly for Lithium Orotate. But does not technically fit the definition of a Vitamin.

• Vitamin B14 is thought to be a combination of Vitamin B10 and Vitamin B11. As of yet it has not been isolated as a specific substance. Currently, very little is known about Vitamin B14. It was isolated from wine, one theory suggest that it may be the metabolite of Xanthopterin.

• Vitamin B15 is the Pangamic acid, also known as Pangamate. It is found in various forms, most popularly as a dietary supplement and drug, initially by Ernst T. Krebs and his son, as a medicinal compound for use in treatment of a wide range of diseases.

• Vitamin B16 is the other name for Di-methyl-glycine (DMG), a derivative of the amino acid glycine and it is synthesized by the human body from Choline. It can be found in beans and liver, and unlike true B vitamins, deficiency of DMG in the diet does not lead to any ill -effects. Also, it can be synthesized by the human body in the Citric Acid (or Krebs) cycle meaning it does not meet the definition of a vitamin.

• Vitamin B17 has been used for Nitrilosides, Amygdalin or Laetrile which are found in a number of seeds, sprouts, beans, tuberous vegetables and grains. It is thought to be toxic in large quantities, some make the bold claim that it is effective in treating cancer and act even acts as a prevention method despite a lack of scientific evidence.

Vitamins - Major Functions, Dietary Sources, RDA or AI

• Vitamin A (retinoids) and provitamin A (carotenoids)

  • Function: Light and color, promote growth, prevent drying of skin and eyes, promote resistance to bacterial infection

  • Sources: Liver, fortified milk, fortified breakfast cereals; Provitamin A: Sweet potatoes, spinach, greens, carrots, cantaloupe, apricots, broccoli

  • RDA or AI: Men: 900μg; Women: 700μg

• Vitamin D (chole-and-ergocalciferol)

  • Function: Facilitate absorption of calcium and phosphorus. Maintain optimal calcification of bone

  • Sources: Vitamin D fortified milk, fortified breakfast cereals, Fish oils, sardines, salmon

  • RDA or AI: 15μg

• Vitamin E (tocopherols)

  • Function: Act as antioxidant: Prevent beak-down of vitamin A and unsaturated fatty acids

  • Sources: Vegetable oils, some greens, some fruits, fortified breakfast cereals

  • RDA or AI: 15 mg

• Vitamin K (phyilo- and menaquinone)

  • Function: Help from prothrombin and other factors for bold clotting and contribute to bone metabolism

  • Sources: Green vegetables, liver

  • RDA or AI: Men: 120 μg; Women: 90 μg

• Thiamin (B1)

  • Function: Coenzyme involved in carbohydrate metabolism; nerve function

  • Sources: Sunflower seeds, pork, whole and enriched grains, dried beans, peas, brewers yeast

  • RDA or AI: Men: 1.2 mg; Women: 1.1 mg

• Riboflavin (B2)

  • Function: Coenzyme involved in energy metabolism

  • Sources: Milk, mushrooms, spinach, liver, enriched grains

  • RDA or AI: Men: 1.3mg; Women: 1.1 mg

• Niacin (B3)

  • Function: Coenzyme involved in energy metabolism, fat synthesis, fat breakdown

  • Sources: Mushrooms, bran, tuna, salmon, chicken, beef, liver, peanuts, enriched grains

  • RDA or AI: Men: 16 mg; Women: 14 mg

• Pantothenic acid (B5)

  • Function: Coenzyme involved in energy metabolism, fat synthesis, fat breakdown

  • Sources: Mushroom, liver, broccoli, eggs; most foods have some

  • RDA or AI: 5 mg*

• Biotin (B7)

  • Function: Coenzyme involved in glucose production, fat synthesis

  • Sources: Cheese, egg, yolks cauliflower, peanut butter, liver

  • RDA or AI: 30 μg

• Vitamin B6 pyridoxine, and other forms

  • Function: Coenzyme involved in protein metabolism, neurotransmitter synthesis, hemoglobin synthesis, many other functions

  • Sources: Animal protein foods, spinach, broccoli, bananas, salmon, sunflower seeds

  • RDA or AI: 1.3 mg

• Folate (folic acid) (B9)

  • Function: Coenzyme involved in DNA synthesis, other functions

  • Sources: Green leafy vegetables, orange juice, organ meats, sprouts, sunflower seeds

  • RDA or AI: 400 μg

• Vitamin B12 (cobalamins)

  • Function: Coenzymes involved in folate metabolism, nerve function, other functions

  • Sources: Animal foods, especially organ meats, oysters, clams (not natural in plants)

  • RDA or AI: 2.4 μg

• Vitamin C (ascorbic acid)

  • Function: Connective tissue synthesis, hormone synthesis, neurotransmitter synthesis

  • Sources: Citrus fruits, strawberries, broccoli, greens

  • RDA or AI: Men: 90 mg; Women: 75 mg

Minerals

• Major Minerals

  • Calcium

  • Sodium

  • Phosphorus

  • Magnesium

  • Sulfur

  • Potassium

  • Chloride

• Trace elements

  • Iron

  • Iodine

  • Fluoride

  • Zinc

  • Selenium

  • Copper

  • Cobalt

  • Chromium

  • Manganese

  • Molybdenum

  • Arsenic

  • Nickel

  • Vanadium

• Minerals play key roles in physiological function.

  • Minerals needed in larger amounts ~> major minerals

  • Those needed in smaller amounts ~> minor minerals.

• Either RDA or AI exists for each mineral.

Minerals Major Functions, Dietary Sources, RDA or AI*

• Sodium

  • Function: Functions as a major ion of the extracellular fluid; aids nerve impulse transmission

  • Sources: Table salt, processed foods, condiments, sauces, soups, chips

  • RDA or AI: 1500 mg*

• Potassium

  • Function: Functions as a major ion of intracellular fluid; aids nerve impulse transmission

  • Sources: Spinach, squash, bananas, orange juice, other vegetables and fruits, milk, meat, legumes, whole grains

  • RDA or AI: 4700 mg*

• Chloride

  • Function: Functions as a major ion of the extracellular fluid, participates in acid production in stomach, aids nerve transmission

  • Sources: Table salt, some vegetables, processed foods

  • RDA or AI: 2300 mg*

• Calcium

  • Function: Provides bone and tooth strength; helps blood clotting; aids nerve impulse transmission; required for muscle contractions

  • Sources: Dairy products, canned fish, leafy vegetables, tofu, fortified orange juice (and other fortified foods)

  • RDA or AI: 1000 mg

• Phosphorus

  • Function: Required for bone and tooth strength; serves as part of various metabolic compounds; functions as major ion of intracellular fluid

  • Sources: Dairy products, processed foods, fish, soft drinks, bakery products, meats

  • RDA or AI: 700 mg

• Magnesium

  • Function: Provides bone strength; aids enzyme function; aids nerve and heart function

  • Sources: Wheat bran, green vegetables, nuts, chocolate, legumes

  • RDA or AI: Men: 420 mg Women: 320 mg

• Iron

  • Function: Used for hemoglobin and other key compounds used in respiration; used for immune function

  • Sources: Meats, spinach, seafood, broccoli, peas, bran, enriched breads

  • RDA or AI: Men: 8 mg; Women 18 mg

• Zinc

  • Function: Required for enzymes, involved in growth, immunity, alcohol metabolism, sexual development, and reproduction

  • Sources: Seafoods, meats, greens, whole grains

  • RDA or AI: Men: 11 mg; Women: 8 mg

• Selenium

  • Function: Aids antioxidant system

  • Sources: Meats, eggs, fish, seafoods, whole grains

  • RDA or AI: 55 μg

• Iodide

  • Function: Aids thyroid hormone

  • Sources: Iodized salt, white bread, salt-water fish, dairy products

  • RDA or AI: 150 μg

• Copper

  • Function: Aids in iron metabolism; works with many enzymes, such as those involved in protein metabolism and hormone synthesis

  • Sources: Liver, cocoa, beans, nuts, whole grains, dried fruits

  • RDA or AI: 900 μg

• Fluoride

  • Function: Increases resistance of tooth enamel to dental caries

  • Sources: Fluoridated water, toothpaste, dental treatments, tea, seaweed

  • RDA or AI: Men: 4 mg; Women: 3 mg

• Chromium

  • Function: Enhances blood glucose control

  • Sources: Egg yolks, whole grains, pork, nuts, mushrooms, beer

  • RDA or AI: Men: 30-35 μg; Women:20-25 μg

• Manganese

  • Function: Aids action of some enzymes, such as those involved in carbohydrate metabolism

  • Sources: Nuts, oats, beans, tea

  • RDA or AI: Men: 2.3 mg; Women: 1.8 mg

• Molybdenum

  • Function: Aids action of some enzymes

  • Sources: Beans, grains, nuts

  • RDA or AI: 45 μg

Take Home Messages (Micro Nutrients)

• Water is essential for life and most individuals will lose about 2500 ml/day of water in urine. Exercise will result in an additional loss of water due to sweating. Often forgotten macronutrient!

• The fat-soluble vitamins include A, D, E, and K. These can be stored in the body in large quantities and toxicity can develop.

• The water-soluble vitamins include thiamin, riboflavin, niacin, B6, folic acid, B12, pantothenic acid, biotin, and C. Most of these vitamins are involved in energy metabolism. Vitamin C is involved in the maintenance of bone, cartilage, and connective tissue.

• Minerals are inorganic elements that are needed in small amounts and are used as components of several structures, and act as signaling molecules

Proposed Health Eating Plans-Examples

• So what constitutes a healthy diet???

• No one size fits all!

• Healthy U.S.-Style Eating Plan

  • Focus on nutrient density from five major food groups (Vegetables, Fruits, Grains, Dairy products, and Protein foods)

• Healthy Mediterranean-Style Eating Pattern

  • Similar to healthy U.S. style eating plan but contains less dairy and more fruit and seafood

• Healthy Vegetarian Eating Pattern

  • Emphasis on more legumes (beans and peas), soy products, nuts, seeds, and whole grains

• Dietary Approaches to Stop Hypertension (DASH)

  • Similar to healthy U.S. style eating plan with focus on reducing hypertension and risk factors for cardiovascular disease

Healthy Eating Plans

• Numerous healthy eating plans have been proposed

• Common elements exist among eating plans

  • Abundant fruits and vegetables

  • Whole grains rather than refined grains

  • Moderate amounts of foods high in protein

    • Seafood, beans and peas, nuts, seeds, soy products, meat, poultry, eggs

  • Limit amounts of foods high in added sugars

  • More oils than solid fats

  • Most are low in full-fat milk and milk products,

    • Some having substantial amounts of low-fat milk and milk products

Take Home Messages (Dietary Guidelines)

• The Dietary Guidelines for Americans is updated every five years using the latest research.

• Several healthy eating plans have been proposed including:

  • Healthy U.S. Style Eating Patterns

  • Healthy Mediterranean Style Eating Pattern

  • Dietary Approaches to Stop Hypertension (Dash).

• The U.S. Department of Agriculture's MyPlate promotes a personalized approach to healthy eating and physical activity.

• A common technique to analyze your diet is the 24-hour recall method which includes food records for 3-4 days per week.

Nutrition and body weight control

• Obesity has become a public health concern in the United States and Abroad.

• Body composition is more important than just “mass”

• Many factors account for the risk of obesity (high % body-fat) including genetic / cultural / environmental factors

• Physical activity and Nutrition both play important roles in maintaining a healthy body composition

  • Nutrition -> new energy (carbon) entering the body

  • AMDR’s: 45-65%-CHO, 20-35%-Fat, 10-35%-Protein (while meeting micro nutrient needs)

  • Physical activity -> a way to remove energy (carbon) from the body

  • Individuals can influence their EER and alter body composition.

• Get at: Energy Balance (carbon balance)

Energy Balance

• Static energy balance

  • If the energy consumed is equal to the energy expended, body mass will remain relatively constant

• Dynamic energy balance

  • A change in energy intake without a change in energy expenditure results in changes in body weight

  • Energy expenditure also increases, and weight is maintained at a new, higher level

• Increase of energy stores = energy intake > energy expenditure

• No change of energy stores energy intake = energy expenditure

If equations

• If Energy intake > Energy expenditure, right side of the equation is positive

  • So change in body store is positive

• If Energy intake < Energy expenditure, right side of the equation is negative

  • So change in body store is negative

Contributors to energy expenditure

• Basal metabolic rate

• Thermic Effect of food

• Physical activity

Thermic effect of food

• Thermogenesis: “Heat generation” and energy expenditure can occur due to both the thermic effect of feeding and from brown adipose tissue.

  • Thermic effect of feeding (TEF)

    • Increased energy expenditure following ingestion of meals

    • Small part of total energy expenditure (10–15%)

    • Not predictive of obesity

  • Non-shivering thermogenesis (BAT)

    • Increases heat production (and energy expenditure) in response to (SNS) norepinephrine and epinephrine

    • Metabolic cycles in which ATP is lost due to UCP in mitochondrion

    • Also due to Na^+/K^+ pump activity

Energy Expenditure RMR/BMR

• Basal metabolic rate (BMR)

  • Rate of energy expenditure under standardized conditions

    • Supine position, immediately after waking, 12–18 hrs following a meal

    • Similar to resting metabolic rate (RMR)

  • Changes in response to altered energy balance

    • Dieting or fasting reduces BMR

    • Overfeeding increases BMR

    • Exercise can maintain BMR during dieting

  • Represents 60–75% total energy expenditure

    • Lower in women, declines with age

    • Related to fat-free mass

Graph Description

• This graph represents an example male who is 1.8m tall and 100kg attempting to reach 70kg with a caloric deficit of 1000kcal per day of EER over about 30 weeks

• As body mass decreases the EER decreases.

• This means that the caloric restriction to create negative energy balance will increase over time.

• This can be accomplished via decrease intake (kcals), increasing the PA coefficient, or some combination

BMR, Body comp, and age

• The figures from this study show that the BMR is associated with age and body composition.

• The differences observed between males and females are mostly due to the differences seen in FFM rather than fat mass

Physical activity and energy expenditure

• Physical activity and exercise

  • Includes exercise and occupational physical activity

  • Accounts for 5–40% total energy expenditure; depends on activity level

• PA is an important factor in determining obesity

  • Inverse relationship between physical activity and %BF

  • Individuals accumulating more than 10,000 steps per day are more likely to be in “normal” BMI range

Energy Balance Equation

• Change in body macronutrient energy stores=Energy intake (food consumption) - Energy expenditure (REE + PA/E + TEF)

  • Fat (White fat cells)

  • Proteins (Cellular proteins)

  • Carbohydrates (Glycogen)

• Sedentary

  • PA/E 15%

  • TEF 5-10%

  • REE 75-80%

• Active

  • PA/E 20-45%

  • TEF 5-10%

  • REE 50-75%

Take Home Messages (Energy Expenditure)

• The BMR represents the largest fraction of total energy expenditure in sedentary persons. The BMR decreases with age, and on average women have lower BMR values than men (related to fat-free mass).

• A reduction in caloric intake by dieting or fasting can reduce the BMR, while physical activity is important in maintaining it.

• Thermogenesis and the Thermic Effect of Food vary among individuals but generally do not contribute large amounts of energy expenditure. These are not predictive of obesity

• There is an inverse relationship between physical activity and body weight.

Diet and Weight Control

• Diets high in fat are linked to obesity

  • Fat grams contain twice as many calories as carbohydrates

  • Nutrient balance can most easily be achieved with a low-fat diet (although can be achieved in any manner)

  • Calories count and must be considered!

    • This is regardless of where they come from: CHO, Fat, Pro, EtOH

• Adherence to the diet is more important than the type of diet followed

  • This is why it is important to choose diets that you can maintain

• Calories from foods and beverages should be balanced with calories expended

  • This is done gradually over the long-haul

  • Gradually decrease caloric intake and increase physical activity

Weight Loss By Diet Type and Adherence Pattern

• Low CHO diet (Like keto diet)

• Low Fat diet (High in CHO)

Calorie of Exercise vs. Calorie Restriction

• In many studies, diet (i.e., caloric restriction) results in more weight loss than exercise alone

  • Due to preserved lean mass as well as difficulty creating caloric deficits via PA

• However, when exercise energy expenditure (700 kcal/day) is matched to dietary energy deficit of 700 kcal/day both treatments result in the same amount of weight loss

  • Key point-Exercise group lost more fat and preserved muscle mass compared to diet alone

Exercise and Body Composition

• Individuals who exercise generally have lower body weight and percent fat

• Weight loss in conjunction with exercise

  • Less lean body mass is lost

  • More fat mass is lost

• In general, those doing the largest amount of physical activity had the largest changes in percent body fat

• By preserving lean mass, exercise helps to maintain BMR, and contributes to the direct caloric expenditure thus reducing the amount of dietary restriction necessary to reduce or maintain weight.

Take Home Messages (Diet & Weight Control)

• Calories do count, and they must be considered in any diet aimed at achieving or maintaining weight-loss.

• Exercise is as effective as diet in achieving weight loss when matched in terms of caloric deficit; however, improvement in physical fitness only occurs in those during the exercise.

• When weight loss occurs with an exercise and diet program, less lean body mass is lost than when the same weight loss is achieved by diet alone.

Potential issues/problems

• Weight Management was for the purpose of optimizing health

• The goal is not necessarily weight loss, but maintaining weight within healthy limits.

  • Body composition was more important than absolute mass / weight

  • Not everyone will look the same at the same weight or body composition due to individual differences

• Healthy eating, lifestyle/physical activity, and body weight all exist along a continuum.

  • Moving too far to either extreme maybe considered disordered eating and can have adverse health consequences.

Healthy Lifestyle Continuum

• Healthy eating

  • Anorexia

  • Binge eating disorder

• Accurate body image

  • Exaggerated body image

  • Reduced body image

  • Muscle dysmorphia

• Healthy exercising habits

  • Excessive exercise

  • Muscle dysmorphia

  • Sedentary lifestyle

• Malnutrition

  • Anorexia

  • Excessive eating

    • Anorexia

    • Bulimia

    • Binge eating disorder

• Bulimia

  • Bulimia

  • Binge eating disorder

  • Muscle dysmorphia

  • Muscle dysmorphia

Disorders with body image and weight management

• There is an interplay between the way we see ourselves, eat, and exercise

  • When different aspects of these three becomes overly exaggerated, there is a danger of developing a disorder

  • There can be disordered eating or exercising without falling into the category of a single disease

• Anorexia Nervosa

• Bulimia Nervosa

• Binge Eating Disorder

• Muscle Dysmorphia

Anorexia nervosa

• Restriction of energy intake relative to requirements leading to significantly low body weight is a core feature of anorexia nervosa. However, individuals with anorexia nervosa also display a fear of gaining weight or of becoming fat, or persistent behavior that interferes with weight gain, as well as specific disturbances in relation to perception and experience of their own body weight and shape.

  • Mild: BMI >17kg/m2

  • Moderate: BMI 16-16.99 kg/m2