Chapter 8: Nutrition, Obesity, and Eating Disorders Flashcards
overweight
body weight that exceeds the desirable weight for a person of a given HEIGHT, AGE, and BODY SHAPE
obesity
excessive accumulation of body fat
glycemic index
ranks carbohydrates based on how quickly your body converts them to the sugar glucose.
glycemic load
is a measure of how much a certain food will raise a person’s glucose level.
paying attention to these is very important because your body performs best when blood sugar is relatively constant. when it drops too low, you feel lethargic and hungry; when it’s too high, your pancreas produces more insulin, which brings your blood sugar back down by converting the excess sugar to stored fat
fat
a major source of energy and also helps the body absorb essential vitamins.
Transfats are unhealthful and should be avoided altogether. Saturated fats should be consumed in moderation, and mono/polyunsaturated fats are healthful and should be consumed regularly
coronary heart disease
consumption of saturated fat, especially trans fat, both of which become dietary cholesterol in the body, is a contributing factor in many adverse health conditions, including coronary heath disease.
cholesterol is a waxy substance essential for strong cell walls, myelination, and hormone production. the cholesterol that we take in from the fats in our foods is nonessential because the liver manufactures all the cholesterol the body needs
three different types of serum cholesterol
low-density lipoproteins (LDL), triglycerides, and high-density lipoproteins (HDL)
what is the best predictor of heart disease?
amount of LDL and triglycerides in the blood
multiple chronic conditions (MCC)
two or more chronic conditions (lasting a year or more, requiring medical attention and/or limiting daily activities) that affect a person at the same time
what three things determine BMR?
heredity, younger people need fewer calories for the same amount and level of physical activity, and fat tissue has a lower metabolic rate than muscles do
set-point hypothesis
the idea that each of us has a body weight “thermostat” that continuously adjusts our metabolism and eating to maintain our weight within a genetically predetermined range, or set point
adipocytes
collapsible body cells that store fat, and whose presence is indicative of being full of food. Increased adipocytes mean increased hunger.
when adipocytes reach their maximum storage capacity, they divide, a condition called fat-cell hyperplasia. Once the number of fat cells increases in a person’s body, it never decreases, even when the person diets
how many adipocytes does a healthy person have vs an obese person?
20-30 billion vs roughly 200 billion
what areas of the hypothalamus are linked to hunger?
the lateral and ventromedial hypothalamus
describe the role of the pancreas in short-term appetite regulation
the pancreas produces the hormone insulin and assists the body in converting glucose to fat. When glucose levels fall, insulin production increases, and we feel hunger. Conversely, when glucose levels rise, hunger and insulin levels decrease. As time passes since our last meal, the level of glucose in the blood drops
ghrelin (appetite stimulant)
appetite stimulant
the stomach produces ghrelin, which causes the pituitary gland to release growth hormone and stimulates appetite
ghrelin also stimulates receptors on nerve cells in the hippocampus, a brain area involved in learning and memory
peptide YY
appetite suppressant
leptin (fat hormone)
as body fat increases, higher levels of leptin signal the normal brain to suppress hunger. animals with defective leptin genes produce too little leptin and overeat.
as a person gains weight, more leptin is produced - this shuts off appetite, increases energy expenditure, and triggers other mechanisms to restore body weight to its weight set point
body-mass index
a measure of obesity calculated by dividing body weight by the square of a person’s height
although it provides a good estimate of body fat, it’s an incomplete measure of health as it relates to body fat
what are acceptable body fat percentages for men and women?
18-23% for men, and 25-30% for women
what is the biggest problem with BMI?
it reflects total body fat without regard to how it is distributed. while the overall amount of body fat is important, evidence suggests that where body fat is distributed may be even more significant
abdominal obesity
excess fat around the stomach and abdomen; also called male-pattern obesity
weight cycling
repeated weight gains and losses through repeated dieting
biological factors in obesity
heredity determines 50% of the likelihood of obesity. heredity influences BMR, and different genes influence body weight.
despite evidence for the role of biological factors in obesity, it is important to recognize that specific genetic defects only account for about 4% of cases of human obesity, and the role of genetic factors in obesity are polygenic (involve the interaction of several genes)
psychosocial factors in obesity
if your friends are fat, you likely will be too
the presence of acute and chronic stresses are associated with eating in the absence of hunger
poverty-income ratio
the ratio of household income to the poverty threshold after accounting for inflation and family size
cultural and socioeconomic factors or obesity
there is an inverse relationship between obesity and socioeconomic status, and an inverse relationship between obesity and education/occupation level
why are less educated, lower SES people at increased risk for obesity?
lack of access to good health care, less knowledge about the importance of a healthy diet and the hazards of obesity, lower perceived self-efficacy in being able to increase their fruit and vegetable intake, and less exercise. lower accessibility to healthy foods is another issue
food deserts
geographical areas with little or no access to foods needed to maintain a healthy diet
do diets work?
not alone - developing better eating and regular exercise habits are better methods of weight management
why do diets fail?
many people have unrealistic expectations and find it nearly impossible to comply with dietary restrictions for very long
not many people are capable of calculating how many calories their body needs
competitive foods
foods and beverages that are often high in calories, sugar, fat, and sodium that are sold in schools in vending machines, a la carte lines, and student stores
anorexia nervosa
an eating disorder characterized by self-starvation; a distroted body image; and in females, amenorrhea
bulimia nervosa
an eating disorder characterized by alternating cycles of binge eating and purging through such techniques as vomiting or laxative abuse
binge eating disorder
an eating disorder in which a person frequently consumes unusallualy large amounts of food
biological factors in eating disorders
biochemical abnormalities at all levels of the hypothalamic-pituitary adrenal axis are associated with both anorexia and bulimia
