Chapter 18: Nutrition, Body Composition, and Weight Management

nutrition

the study of nutrients and their action, interaction, and contribution to a healthy body

nutrients

substances needed for bodily function and many nutrients (about 50) that are essential for life

essential nutrient

a nutrient that must be supplied in the diet because the body is incapable of synthesizing an adequate amount for bodily needs

what are the three vital functions of nutrients?

to provide energy required by cells, promote growth and development, and regulate metabolism

what are the two major classes of nutrients?

macronutrients (water, carbohydrates, proteins, fats) and micronutrients (vitamins, minerals, and trace elements)

what are the two classes of carbohydrates?

simple and complex carbohydrates

simply carbohydrates include monosaccharides and disaccharides, and complex carbohydrates contain three or more monosaccharides bonded together into one molecule

what is the difference between non-essential and essential amino acids?

a non-essential AA can be synthesized in the body’s cells and does not need to be consumed in the diet, and essential AA cannot be synthesized in the body’s cells and must be consumed in the diet

what are the three major classes of lipids?

triglycerides, phospholipids, and sterols

what are the functions of triglycerides?

they provide a major source of stored energy for bodily functions in the white blood cells and serve as a storage site for fat-soluble vitamins, insulation for the body, and protective cushioning for the vital organs

what are the functions of phospholipids?

they are necessary structural components of cell membranes

what are the functions of sterols?

they are not a fuel source but are needed to synthesize vital substances such as vitamin D, cortisol, testosterone, and estrogen

what percent body fat results in a higher body water content and why?

a lower percent body fat (higher percent lean tissue) results in a higher body water content because lean tissue is composed of about 75 percent water, while fat cells only contain about 5 percent water by mass

what is a vitamin?

organic substances that participate in metabolic processes needed for life

what are the criteria for a compound to be classified as a vitamin?

the body must be unable to synthesize it or make enough to sustain good health, the compound must be found naturally in foods, and health problems must occur due to the compound missing from the diet

what are the fat-soluble vitamins?

vitamins A D E K

what are the water-soluble vitamins?

thiamin, riboflavin, niacin, vitamin B-6, biotin, pantothenic acid, folate, and vitamin C

what vitamins are involved in maintaining health for oxidative stress (antioxidants)?

vitamin E, vitamin C, some carotenoids

what vitamins are involved in maintaining health for energy metabolism?

thiamin, riboflavin, niacin, pantothenic acid, biotin, vitamin B-12, vitamin B-6

what vitamins are involved in maintaining health for bone health?

vitamin A, vitamin D, vitamin K, vitamin C

essential minerals

minerals that cannot be synthesized in the body and must be consumed in the diet

major minerals

minerals that the body requires in more than 100 mg/day

trace minerals

minerals that the body requires in amounts less than 100 mg/day

major minerals essential for health

calcium, phosphorous, potassium, sulfur, sodium, chloride, magnesium

trace minerals essential for health

iron, manganese, copper, iodide

dietary reference intake (DRI)

a general umbrella term including six sets of standards for dietary intake

estimated average requirement (EAR)

the daily intake of a nutrient that will meet the needs of 50% of people within a specific age group

recommended dietary allowance (RDA)

the quantity of each nutrient required to meet the needs of 97-98% of healthy persons within a specific life stage

adequate intake (AI)

nutrient levels are assumed to be adequate when there is insufficient data to determine the RDA

tolerable upper intake levels (TUIL)

the highest nutrient intake level that will not pose a health risk

estimated energy requirement (EER)

the average dietary energy intake predicted to maintain energy balance for healthy people maintaining their current weight

daily value (DV)

the recommended intake of each macronutrient and micronutrient per day

acceptable macronutrient ranges (AMR)

the ranges for fats, CHO, and proteins that provide adequate intake of essential nutrients to reduce the risk of developing disease

what is the purpose of the nutritional facts panel on commercial food products?

it is used to display the serving size and daily value for calories, macronutrients, and micronutrients in a given food to allow consumers to make more informed food choices

acceptable range for carbohydrate consumption

45-65% total energy intake

acceptable range for fat consumption

20-35% of total energy intake

acceptable range for protein consumption

10-35% of total energy intake

glycemic index

a measurement of how a specific carbohydrate-rich food elevates blood glucose levels

glycemic load

multiplies glycemic load by the amount of carbohydrate in the given serving of food

high-density lipoproteins (HDL)

function to remove cholesterol from the blood and provide protection against heart disease

low-density lipoprotein (LDL)

cause a buildup of cholesterol in the arteries and increase the risk of heart disease

what is a simple way to monitor for dehydration?

can be easily monitored by observing the color of the urine. clear or very light yellow urine indicates proper hydration

what are the four major points contained in the current dietary guidelines for americans 2020-2025?

americans must follow a consistent, healthy dietary pattern over their lifespan, focus on a variety of nutrients and amount of food, limit calories due to added sugars, saturated fats, and sodium, and should make a general switch to healthier food and beverage choices

body composition

the makeup of tissues int he human body, and is used in reference to percent body fat

what is the two compartment model of body composition?

it separates body fat percentage into fat mass and fat-free mass, or lean tissue

body mass index

the most common technique in health care to assess body composition. it looks at the relationship between and individual’s height and weight. it is very straightforward and easy to understand, but it does not take body composition into account, which can cause the results to be inaccurate for certain populations, such as very muscular individuals

five methods for determining body composition

underwater weighing (gold standard), air displacement plethysmography (BodPod), bioelectrical impedance analysis (BIA), skinfold technique, dual-energy x-ray absorptiometry (DEXA)

what is the healthy range of percent body fat for young adult women?

20 to 35 percent body fat

what is the healthy percent body fat for young adult men?

8 to 22 percent body fat

what is the energy balance equation and the factors that contribute to energy expenditure?

the equation states that the change in body macronutrient energy stores is equal to energy intake, or food consumption, minus energy expenditure. energy expenditure is made up of resting energy expenditure, physical activity/exercise, and the thermic effect of food

what are the primary storage sites for carbohydrates?

the liver and skeletal muscle

what are the primary storage sites for fat?

white adipocytes as triglycerides, brown adipocytes (less common), and beige adipocytes

what are the primary storage sites for protein?

as cellular proteins and are not kept as a body fuel source

low carbohydrate diet plan

they require different amounts of carbohydrates depending on the plan, but the lack of carbohydrates is often made up for by extra consumption of fats and/or protein. these diets are proposed to increase satiety and decrease appetite, allowing the individual to be satisfied with a lesser amount of calories consumed

low fat diet plan

include the Ornish diet or the Mediterranean diet, which advise the removal of cholesterol and fats from the diet and replacing that with whole grains, vegetables, and other healthful foods

high protein diets

designed to mimic the diets or prehistoric ancestors, and include fish, lean meats, non-starchy vegetables, fruits, and nuts. these diets increase satiety and ensure adequate protein and amino acid intake

nutritionally balanced diets with restricted calories

include weight watchers or Jenny Craig and follow the AMDR for the macronutrients but with restricted calories. these plans ensure weight loss and are more sustainable than other diets

why may macronutrient content of a diet not be the key to weight loss?

diets emphasizing each of the macronutrients all resulted in similar amounts of weight loss. therefore, there is not a significant indication that one of the macronutrients is better than the others in achieving weight loss

what is the impact of a low calorie diet on loss of fat free mass and REE?

low calorie diets promote loss of fat-free mass, which causes a decrease in resting metabolic rate. a loss of muscle mass (lean tissue) results in a loss of strength and energy.

what is the impact of combining exercise with a low calorie diet on loss of fat free mass and REE?

when combined with exercise or strength training, more lean tissue mass is retained which also maintains energy expenditure and resting metabolic rate

what are the five steps to achieving a healthy percent body fat?

measuring body composition, determining if the current body fat percentage exceeds the healthy range or determining desired weight loss, establishing daily total energy expenditure, computing the necessary calorie deficit to achieve the desired body weight, and formulating the weight loss plan