chapter 9
The two major ways in which the body spends energy are
(1) to fuel its basal metabolism and (2) to fuel its voluntary activities.
appetite
-can experience appetite without hunger. Factors affecting appetite; Appetite stimulants or depressants, other medical drugs. Cultural habits (cultural or religious acceptability of foods). Environmental conditions (people often prefer hot foods in cold weather and vice versa). Hormones (for example, sex hormones). Inborn appetites (inborn preferences for fatty, salty, and sweet tastes). Learned preferences (cravings for favorite foods, aversion to trying new foods, and eating according to the clock). Social interactions (companionship, peer influences). Some disease states (obesity may be associated with increased taste sensitivity, whereas colds, flu, and zinc deficiency reduce taste sensitivity).
ghrelin
-polypeptide ghrelin is a powerful hunger-stimulating hormone that opposes weight loss -secreted by stomach cells but works in the hypothalamus and other brain tissues to stimulate appetite and increase body weight and fatness.
According to the American College of Sports Medicine
150 to 250 minutes per week of physical activity of moderate intensity can help prevent initial weight gain. More than 250 minutes per week, particularly when combined with a lower calorie intake, promotes weight loss and may prevent regain after loss. Both aerobic (endurance) and muscle-strengthening (resistance) activities are beneficial, but most people must also restrict calorie intakes to achieve meaningful weight loss.
central obesity
A person's body fat distribution modulates the risks from obesity. Fat collected deep within the central abdominal area of the body, called visceral fat (stored in abdominal cavity) , results in central obesity, which poses greater risks of major chronic diseases and death Central obesity is associated with the metabolic syndrome-(Combination of central obesity, diabetes or prediabetes, high blood glucose, high blood pressure, and altered blood lipids) and, independently of BMI, contributes to heart disease, cancers, diabetes, and related deaths Visceral fat increased risk of death from all causes Metabolic syndrome: heart disease "Apple" profile fat distribution-men & post-menopausal women "Pear" hip and thigh fat, clings more stubbornly often 1.Factors affecting body fat distribution: gender, menopause, alcohol intake, physical activity
leptin
Adipokine hormone: suppresses appetite related to amount of adipose tissue increased adipose tissue = increased leptin -leptin travels from the adipose tissue via the bloodstream to the brain's hypothalamus, where it triggers signals that suppress appetite, dampen sensitivity to sweet taste, increase energy expenditures, and, ultimately, produce body fat loss. A loss of body fatness, in turn, brings the opposite effects—suppression of leptin production, increased appetite, reduced energy expenditure, and accumulation of fat
BMI values have two major drawbacks: they fail to indicate how much of a person's weight is fat and where that fat is located. These drawbacks limit the value of the BMI for use with:
Athletes (because their highly developed musculature falsely increases their BMI values). Pregnant and lactating women (because their increased weight is normal during child bearing). Adults older than age 65 (because BMI values are based on data collected from younger people and because people "grow shorter" with age). Women older than age 50 and others with too little muscle tissue (they may be overly fat for health yet still fall into the normal BMI range).
evaluate the health risks of obesity by way of two physical indicators
BMI-body mass index; defines average relative weight for height in people older than 20 years, correlates significantly with body fatness and risk of death and diseases such as heart disease, stroke, diabetes, and nonalcoholic fatty liver disease second indicator is waist circumference, reflecting the degree of central obesity in proportion to total body fat. -if the waist circumference exceeds 35 inches for women and 40 inches for men. -•Disease risk profile; the more factors like poor dietary habits, sedentary lifestyle, smoking, family history, etc,
other ways to measure Body Composition and Fat Distribution
Central adiposity can be assessed by measuring waist circumference. The percentage of fat in a person's body can be estimated by using skinfold measurements. Body fat distribution can be revealed by radiographic techniques.
daily energy balance
Change in energy stores equals food energy taken in minus energy spent on metabolism and muscle activities. -Change in energy stores = energy in − energy out. Energy in•Foods and beverages•Measured in calories •Energy out•Varies widely•Lifestyle and metabolism
strategies best for weight loss To achieve and maintain a healthy body weight, set realistic goals, keep records, eat regularly, and expect to progress slowly. Be aware of energy density, make the diet adequate and balanced, eliminate excess calories, and limit alcohol intakes.
Choose an Appropriate Calorie Intake Nutrition professionals often use an overweight person's BMI to calculate the number of calories to cut from the diet. Dieters with a BMI of 35 or greater are encouraged to reduce their daily calories by up to 1,000 calories from their usual intakes. People with a BMI between 25 and 35 should reduce energy intake by 500 to 750 calories a day to produce a pound or two of weight loss each week while retaining lean tissue make intakes adequate; Fruit, vegetables, nuts, and legumes. Fish; poultry without skin; low-fat or nonfat milk products (or fortified soy or other legume substitutes). Whole grains. Moderate amounts of unsaturated oils Avoid Portion Pitfalls Pay careful attention to portion sizes Read Menu Labels Meal Spacing Three meals a day is standard in our society, but no law says you can't have four or five—just be sure they are smaller, of course. People who eat small, frequent meals can be as successful at weight loss and maintenance as those who eat three. Also, eat regularly, before you become extremely hungry. When you do decide to eat, eat the entire meal you have planned for yourself. *be careful with snacks **Hungry people are likely to awaken at night to eat, a symptom of night eating syndrome energy density; people who wish to be leaner and to improve their nutrient intakes would be well advised to select mostly foods of low energy density. In general, foods high in fat or low in water, such as fatty meats, cookies, or chips, rank high in energy density; foods high in water and fiber, such as fruit and vegetables, rank lower. Nonnutritive sweeteners may or may not help Prepared Meals Alcohol = calories
Bulimia Nervosa is more prevalent than anorexia nervosa
Eating large amount of food in short period of time. Loss of control during binges & compensation behaviors afterwards, such as vomiting or fasting. Frequent binges and compensations (at least once a week for three months). False perceptions of body weight or shape; exaggerations of the importance of body weight or shape in self-evaluation.
Suggestions for teachers and coaches
Encourage positive eating and physical behaviors that can be maintained over a lifetime; discourage dieting, skipping of meals, or the use of diet pills. Promote a positive body image; do not use body dissatisfaction as a motivator for behavior change. Encourage frequent and enjoyable family meals consumed at home; discourage hasty meals eaten alone. Focus not on weight but on healthy eating and physical activities; facilitate healthy eating and physical activity at home. Ask about mistreatment or bullying and address this issue with patients and their families. Carefully monitor necessary weight loss and prevent the development of semi-starvation.
A person wishing to know how much energy he or she needs in a day to maintain weight might look up his or her
Estimated Energy Requirement (EER) -Taller people need proportionately more energy than shorter people to balance their energy budgets because their greater surface area allows more energy to escape as heat. Older people generally need less than young people due to slowed metabolism and reduced muscle mass, which occur in part because of reduced physical activity. these losses may not be inevitable for people who stay active. On average, though, energy need diminishes by 5 percent per decade beyond the age of 30 years. Age. The BMR declines with age, so age helps determine EER values. Gender. Women generally have less lean body mass than men; in addition, women's hormone fluctuations influence the BMR, raising it just prior to menstruation. Body size and weight. The higher BMR of taller and heavier people calls for height and weight to be factored in when estimating a person's EER. Physical activity. To help in estimating the energy spent on physical activity each day, activities are grouped according to their typical intensity Growth. The BMR is high in people who are growing, so pregnant women and children have their own sets of energy equations.
external theories of obesity
FOOD!!! Source of pleasure, we can easily override our body's satiety & hunger signals; round-the-clock access to rich, palatable foods •Emotional indicators •Larger portions; larger dishes & sizes •Addictive food supply --->dopamine activity (signals reward area of brain) Physical inactivity •Screen time •Sedentary jobs •Neighborhoods •Built environment (no sidewalks, parks) •Low-income & rural areas -->food deserts •National goals to slow or reverse obesity epidemic
strategies for weight gain
High caloric density diet • increase daily caloric intake •Choose nutritious foods •Larger portion sizes, more snacks •Physical activity: resistance training builds muscle Tips for Gaining Weight In General: Eat enough to store more energy than you expend—at least 500 extra calories a day. Exercise to build muscle. Be patient. Weight gain takes time (a pound per month would be reasonable). Choose energy-dense foods most often. Eat at least three meals a day, and add snacks between meals. Choose large portions and expect to feel full. Specifically: Drink caloric fluids—juice, chocolate milk, milkshakes, smoothies, sweet coffee drinks, sweet iced tea. Pair raw vegetables with rich mayonnaise dips and stuff raw celery with tuna salad (use oil-packed). Drizzle olive oil on cooked vegetables and salads. Add avocado to salads instead of cucumber, top with olives instead of pickles, and choose guacamole over salsa. Toast split whole-grain muffins instead of bread. Add whipped topping to fruit. Add margarine and sour cream to potatoes and creamy sauces to other vegetables. In Addition: Cook and bake often—delicious cooking aromas whet the appetite. Invite others to the table—companionship often boosts eating. Make meals interesting—try new vegetables and fruit, add crunchy nuts or creamy avocado, and explore the flavors of herbs and spices. Keep a supply of favorite snacks, such as trail mix or granola bars, handy for grabbing. Control stress and relax. Enjoy your food.
Two other factors also affect body fat distribution.
High intakes of alcohol are associated with central obesity, whereas high levels of physical activity correlate with leanness
Metabolic Syndrome
High triglyceride level — 150 milligrams per deciliter,(mg/dL), or 1.7 millimoles per liter (mmol/L), or higher of this type of fat found in blood •Reduced high-density lipoprotein (HDL) cholesterol — less than 40 mg/dL (1.04 mmol/L) in men or less than 50 mg/dL (1.3 mmol/L) in women of this "good" cholesterol •Increased blood pressure — 130/85 millimeters of mercury (mm Hg) or higher •Elevated fasting blood sugar — 100 mg/dL (5.6 mmol/L) or higher •Cluster of conditions increasing risk for stroke, diabetes, and heart disease
clues to Fad Diets and Weight-Loss Scams
It may be a fad diet or weight-loss scam if it: Bases evidence for its effectiveness on anecdotes and testimonials. Blames weight gain on a single nutrient, such as carbohydrate, or constituent, such as gluten. Claims to "alter your genetic code" or "reset your metabolism." Eliminates an entire food group, such as grains or milk products. Fails to include all costs up front. Fails to mention potential risks. Fails to plan for weight maintenance following loss. Guarantees an unrealistic outcome, such as losing 10 pounds in 3 days. Promises easy weight loss with no change in diet or activity; for example, "Lose weight while you sleep." Promotes devices, drugs, products, or procedures not approved by the U.S. Food and Drug Administration (FDA) or not scientifically evaluated for safety or effectiveness. Specifies a proportion of energy nutrients not in keeping with DRI ranges. Recommends using a single food, such as grapefruit, as the key to the program's success. Requires you to buy special products not readily available in ordinary supermarkets. Has any of the other characteristics of quackery
National Academies' Institute of Medicine has put forth these national goals
Make physical activity an integral and routine part of American life. Make healthy foods and beverages available everywhere. Create food and beverage environments in which healthy food and beverage choices become the easy, routine choice. Advertise and market what matters for a healthy life. Develop and enforce legislation and policies aimed at preventing obesity. Strengthen schools as centers that promote fitness and health
eating disorders in athletes
Motivations: enhance performance to meet weight guidelines -Both male and female athletes-Severe energy restriction causes a loss of lean tissue that impairs physical performance and imposes a risk of eating disorders. Risk Factors: •Young age (adolescence). •Pressure to excel in a sport. •Focus on achieving or maintaining an "ideal" body weight, muscular structure, or body fat percentage. •Participation in sports or competitions that emphasize a lean appearance or judge performance on aesthetic appeal, such as gymnastics, wrestling, figure skating, or dance. •Unhealthy, unsupervised weight-loss dieting at an early age.
gimmicks to lose weight
Obesity medications: may help but still need lifestyle changes•OTC "medications" not effective, may carry risks Herbals and botanicals •Sold as 'dietary supplements' •Lack FDA approval •Other gimmicks-Saunas or steam baths •Cellulite -weight-loss "dietary supplement" but has caused cardiac arrest, abnormal heartbeats, hypertension, strokes, seizures, and death. -Brushes, sponges, wraps, creams, and massages intended to move, burn, or break up cellulite are useless for fat loss. Cellulite—the rumpled, dimpled, stubborn fat tissue on the thighs and buttocks—is simply fat, awaiting the body's call for energy
protein, carbs, fats in hunger
Of the three energy-yielding nutrients, protein seems to have the greatest satiating effect during a meal. Therefore, including some protein in a meal—even just a glass of milk—can improve satiation. Many carbohydrate-rich foods, notably those providing slowly digestible carbohydrate and soluble fiber, also contribute to satiation and satiety. Between meals, these foods tend to hold insulin steady, minimizing dips in blood glucose. This stabilizing effect helps to forestall hunger; if blood glucose does dip, the brain sends out hunger signals that prompt eating. Soluble fibers also support colonies of bacteria in the colon that are associated with leanness in some studies. Finally, fat, famous for triggering a hormone that contributes to long-term satiety, goes almost unnoticed by the appetite control system during consumption of a meal. As dieters await news of dietary tactics against hunger, researchers have not yet identified any one food, nutrient, or attribute—not even protein—that is especially effective for weight loss and its maintenance.
other risks of obesity- adiposity based chronic disease
Other Risks An obese person faces a long list of threats in addition to the chronic diseases already named: abdominal hernias, cancers (many types), complications in pregnancy and surgery, flat feet, gallbladder disease, gout, high blood lipids, medication dosing errors, reproductive disorders, skin problems, sleep disturbances, sleep apnea (dangerous abnormal breathing during sleep), varicose veins, and even a high accident rate. So great are the harms that obesity itself is classified as a chronic disease: adiposity-based chronic disease. Some of these maladies start to improve with the loss of just 5 percent of body weight, and risks improve markedly after a 10 percent loss.
Why should fat in the body present an extra risk to the heart?
Part of the answer may involve adipokines, hormones released by adipose tissue Adipokines help to regulate inflammatory processes and energy metabolism in the tissues. In fact, adipose tissue acts as an endocrine organ, orchestrating important interactions with other vital organs such as the brain, liver, muscle, heart, and blood vessels in ways that influence overall health.
the energy-yielding nutrients contribute the excess to body stores as follows: -When energy balance is positive, carbohydrate is converted to glycogen or fat, protein is converted to fat, and food fat is stored as fat. -Alcohol both delivers empty calories and promotes the storage of body fat.
Protein is broken down to amino acids for absorption. Inside the body, these may be used to replace lost body protein and, in a person who is exercising or growing, to build new muscle and other lean tissue. Excess amino acids, after their nitrogen is removed, are used for energy or are converted to glucose or fat. The nitrogen is incorporated into urea and excreted in the urine. Fat is broken down to glycerol and fatty acids in the digestive tract for absorption. Inside the body, the fatty acids can be broken down for energy or stored as body fat with great efficiency. The glycerol can be used for energy or converted to fat and stored Carbohydrate (other than fiber) is broken down to sugars for absorption. In the body tissues, excesses of these may be built up to glycogen and stored, used for energy, or converted to fat and stored. Alcohol is absorbed and, once inactivated, delivers energy that is used as fuel or converted into body fat for storage Almost any food can make you fat if you eat enough of it. A net excess of energy is almost all stored in the body as fat in fat tissue. Fat from food is particularly easy for the body to store as fat tissue. Protein is not held in the body in a storage form. It exists only in muscle and other working proteins. Muscle protein is broken down to yield glucose when the brain runs out of carbohydrate energy. Dietary protein in excess of need contributes to body fat accumulation. Alcohol both delivers empty calories and facilitates storage of body fat.
anorexia nervosa
Restrict calorie intake; body weight too low for age, gender, and health.•Intense fear of body fatness or weight gain•False perception of weight & shape, exaggerated importance of weight, deny danger of severe underweight•Physically: growth & development cease, osteoporosis, organ damage, brain damage, death•Treatment: multidisciplinary & subject to relapse
stop signals
Satiation and Satiety -
causes of eating disorders
Societal pressure for thinness sociocultural, psychological, hereditary, possibly also genetic/neurochemical-Distorted body image: people begin to view the normal, healthy body as too fat Media: convey a message that to be happy, beautiful, and desirable, one must first be thin Severe food restriction: intense stress and extreme hunger that lead to binges and painful emotions
obesity surgery
Successful surgery resulting in weight loss often brings immediate and lasting improvements to diabetes, insulin resistance, high blood cholesterol, hypertension, and heart disease, and reduces the risks of some cancers. The surgery may also cause a shift in the makeup of the intestinal bacteria toward a profile more typically found in lean, healthy people Surgery is not a sure cure for obesity despite advertisements claiming so. Some people do not lose the expected pounds, and others who lose weight initially regain much of it in a few years' time. Some people experience infections; nausea, vomiting, diarrhea, and dehydration; abnormal heart beats and low blood pressure; low blood glucose; confusion, sweating, weakness; and tooth erosion and dry mouth leading to dental disease Severe nutrient deficiencies often pose a major threat to health in the years following surgery. Vitamin D deficiency results in bone abnormalities, and vitamin A deficiency causes night blindness and other vision problems. Thiamin, iron, copper, zinc, vitamin , other B vitamins, and other deficiencies are likely, but can generally be corrected with appropriate supplements. Life-long nutrition and medical supervision following surgery is a must. other options; One is an inflatable, removable balloon that is inserted nonsurgically into the stomach to reduce its capacity, but has caused pain, vomiting, and ulcers, and is under investigation for safety. A second is a device worn outside the body that delivers high-frequency electrical pulses which interfere with nerve communication between the stomach and brain, delaying stomach emptying and producing feelings of fullness. A third is an implanted stomach-draining tube that allows a portion of each meal to be siphoned off after consumption. These procedures require shorter recovery times than for surgery and leave the anatomy of the digestive tract mostly intact.
underweight
Thin people are among the first to die during a siege or in a famine . -the disadvantage in the hospital, where their nutrient status can easily deteriorate if they have to go without food for days at a time -risk of death for surgical patients and for anyone fighting a wasting disease. -People with cancer often die not from cancer itself but from starvation.
satiation
To balance energy intake with energy output, eating behaviors must be counterbalanced with periods of fasting between meals. Being able to eat periodically, store fuel, and then use up that fuel between meals confers a great advantage on people. -between-meal interval is normally about 4 to 6 waking hours—about the length of time the body takes to use up most of the readily available fuel—or 12 to 18 hours at night, when body systems slow down and the need is less Hormones and sensory nerve messages regulate satiety Sensations of pleasure and satisfaction in the mouth decreased with repeated exposure to a particular texture or taste Stomach nerve stretch receptors sense distention -->signal to the brain that the stomach is full Small intestine releases hormones signaling the hypothalamus Brain detects absorbed nutrients in blood --> releases neurotransmitters to suppress food intake -Together, mouth sensations, stomach distention, and the presence of nutrients trigger nervous and hormonal signals to inform the brain's hypothalamus that a meal has been consumed. Satiation occurs; the eater feels full and stops eating.
binge eating and purging
To purge the food from her body, she may use a cathartic—a strong laxative that can injure the lower intestinal tract. Or she may induce vomiting, sometimes with an emetic—a drug intended as first aid for poisoning. After the binge, she pays the price with hands scraped raw against the teeth during gag-induced vomiting, swollen neck glands and reddened eyes from straining to vomit, and the bloating, fatigue, headache, nausea, and pain that follow. strong and persistent cravings, unsuccessful efforts to control intakes, and continuation of the behavior despite physical harm or other negative results •Responds more readily to treatment •Anticipation and planning-->Anxiety -->Urgency to begin -->Rapid uncontrollable consumption of food --> Relief/ relaxation -->Disappointment -->Shame & disgust •Purging: emesis and/or laxatives •Effects: electrolyte imbalances, heart arrhythmias, dental erosion, stomach & esophageal ruptures, heart & organ failure, death •Treatment: multidisciplinary & resistant
Tips for Accepting a Healthy Body Weight
Value yourself and others for traits other than body weight; focus on your whole self, including your intelligence, social grace, and professional and scholastic accomplishments. Realize that prejudging people by weight is as harmful as prejudging them by race, religion, or gender. Use only positive, nonjudgmental descriptions of your body; never use degrading, negative descriptions. Accept positive comments from others. Accept that no magic diet exists. Stop dieting to lose weight. Adopt a healthy eating and exercise lifestyle permanently. Follow the USDA Eating Patterns (Chapter 2 and Appendix E). Never restrict food intake below the minimum levels that meet nutrient needs. Become physically active not because it will help you get thin but because it will enhance your health. Seek support from loved ones. Tell them of your plan for a healthy life in the body you have been given. Seek professional counseling not from a weight-loss counselor but from someone who supports your self-esteem. Join with others to fight weight discrimination and stereotypes.
physical activity
Weight loss not likely with physical activity alone •Muscle strengthening increases lean body mass and metabolically tissue which burns more calories than lean tissue •Feelings of satiation •Decreased stress •Better sleep -move often
Achieving and Maintaining a Healthy Body Weight
What is your motivation? Modest weight loss of even 3 to 5 percent of body weight in a person who is still overweight can quickly produce gains in physical abilities and quality of life, along with improvements in indicators of diabetes and blood lipids. Effort in three realms: diet, activity, behaviors Reality check: takes years/lifetime, there's setbacks, gets harder-not easier at times Set small specific, achievable goals in each realm Keep records
fasting
When fasting or a low-carbohydrate diet depletes glycogen altogether, body protein is called upon to make glucose, while fats supply ketone bodies to help feed the brain and nerves. Fasting and supplements are not needed for weight loss or "cleansing."
eating disorders
anorexia nervosa(not eating), bulimia nervosa(eating too much then vomitting), and binge eating disorder. Anorexia nervosa: refusal to maintain a minimally normal body weight, self-starvation to the extreme, and a disturbed perception of body weight and shape; seen (usually) in teenage girls and young women •Bulimia nervosa: recurring episodes of binge eating combined with a morbid fear of becoming fat; usually followed by self-induced vomiting or purging •Binge eating disorder: criteria are similar to those of bulimia nervosa, excluding purging or other compensatory behaviors Eating Disorders: Up to 24 million Americans, predominantly young women -An estimated 85 percent of eating disorders start during adolescence. Children of this age often exhibit warnings of disordered eating such as restrained eating, binge eating, purging, fear of fatness, and distorted body image.
components of energy expenditure
basal metabolism-50-65% physical activity- 25-50% thermic effect of food- 5-10%
behavior modification for weight control
eliminate inappropriate eating and activity cues. •Suppress the cues you cannot eliminate. •Strengthen cues to appropriate eating and activities. •Repeat the desired eating and physical activity. •Arrange or emphasize negative consequences of inappropriate eating or sedentary behaviors. •Arrange or emphasize positive consequences of appropriate eating and exercise behaviors.
Energy output-Basal metabolism (BMR):
energy to support the body's work, continuous-Voluntary activities-Thermic effect of food: 10% meals calories used for metabolism -The iodine-dependent hormone thyroxine directly controls basal metabolism—the more secreted, the greater the energy spent on basal functions. The rate is lowest during sleep
female athlete triad
potentially fatal triad of medical problems seen in female athletes: low energy availability (with or without disordered eating), menstrual dysfunction, and low bone mineral density. The prevalence of amenorrhea among premenopausal women in the United States is about 2 to 5 percent overall, but it may be well over 60 percent among female athletes. Amenorrhea is not a normal adaptation to strenuous physical training but a symptom of something going wrong.
Hunger:
response to physiological need for food, unpleasant•~4-6 hours after eating •Signals triggered by physical contractions of empty stomach •Hormones from hypothalamus
extreme obesity
the risk of dying equals that from smoking. Major obesity-related chronic disease risks include: Arthritis. Cancers of the breast, colon, endometrium, and other cancers. Diabetes. Heart disease. Kidney disease. Nonalcoholic fatty liver disease. Stroke. *Over 70 percent of obese people suffer from at least one -obesity triples a person's risk of developing diabetes, and even modest weight gain raises the risk.
US overweight epidemic
•70 percent of adults in the United States are overweight or obese -in 1960, about 13% of adults in the U.S. were obese. •Advancement of obesity is decreasing in some groups-children, girls and women. -Obesity rates accelerating among men and boys. -20% of children and adolescents are obese and many more are overweight Underweight (BMI < 18.5) 1.4% Overweight and obese (BMI 25-29.9) 70.7% Obese (BMI 30-39.9) 37.9% Extremely obese (BMI ≥ 40) 7.7%
BMis to watch
•B M I over 30 indicates a need for treatment •B M I of 25 to 29.9 plus more than one disease or risk factor, such as cardiovascular disease, diabetes, or high blood pressure (see below), indicates a need for treatment •B M I of 25 to 29.9 with no other risk factors indicates a need to stop gaining weight
adipokines
•Hormones released by adipose tissue. •Help to regulate inflammatory processes and energy metabolism in the tissues. •In obesity, shift in adipokine balance---> tissue inflammation and insulin resistance. •Chronic inflammation and insulin resistance-->diabetes, heart disease, and other chronic diseases. •Weight loss often reduces inflammation and improves health.
fad diets
•Ineffective for weight-loss maintenance •Do not meet nutrition needs •Limiting carbohydrates •Sugars and refined carbohydrates •Increase in protein •Sources of protein are important for weight loss
Once I've Changed My Weight, How Can I Stay Changed?
•Lifelong commitment •Cultivate healthy habits including physical activity •Self-efficacy - a belief in the ability to succeed •Seek support -People who succeed at maintaining lost weight believe in their own abilities, keep to their eating routines, keep exercising, and keep track of calorie intakes and body weight.
bodies response to energy deficit
•Moderate decreased food intake :body draws on stored energy; moderate calorie restriction & exercise = gradual weight loss sparing lean body mass •Fasting •Body adjustments: underfed body sacrifices the proteins in its lean tissue to supply raw materials from which to make glucose •Death ~ 10 days •Ketosis: breakdown of fat to ketone bodies for nervous tissues; moderate fat stores can live up to 6-8 weeks
Internal Theories of Obesity (energy in)
•Set-point theory: body adjusts metabolism to maintain a set weight (thermostat) •Body organs regulate body fatness •Thermogenesis: body's wasted heat energy •Brown adipose tissue (BAT) is more thermogenic, obesity associated with less BAT •Intestinal microbiota: decrease healthy bacteria= increase obesity in animals •Genetics: genes influence metabolism Metabolic theories attempt to elucidate molecular activities that lead to obesity. Research suggests a relationship between intestinal microbial colonies and obesity. A person's genetic inheritance greatly influences but does not guarantee the development of obesity.
