Weight Management 9.1 Overweight and Obesity ➢ An estimated 70 percent of the adults in the United States are now considered overweight (as defined by a BMI of 25 to 29.9) or obese (BMI of 30 and greater) ➢ Prevalence of overweight among children in the US also rises ○ Worldwide 1.9 billion adults and 41 million children younger than age 5 are overweight or obese ➢ Increasing rates of obesity in countries reflect a global food system that delivers an abundance of ■ Energy dense ■ Ultra processed ■ Affordable ■ Effectively marketed products Fat Cell Development ➢ When “energy in” exceeds “energy out” much of the the excess energy is stored in the fat cells of adipose tissue reflects both the number and size of fat cells. ➢ Fat cells increase rapidly during growing years ○ Of late childhood/ early puberty ➢ After growth stops, fat cells may continue to increase ○ When energy balance is positive ➢ Obese peopel have more fat cells & larger fat cells ○ Fat cells store triglycerides that expand in size ➢ When cells enlarge they stimulate cell proliferation so their numbers increase agan ○ Obesity develops when persons fat cells increase in number, size or both ➢ When ”energy out” exceeds ”energy in,” the size of fat cells dwindles, but not their number. ○ People with extra fat cells tend to regain lost weight rapidly as their fat cells readily fill ■ People with an average number of enlarged fat cells are more successful in maintaining weight losses ● When their cells shrink both cell size and number become normal ○ Prevention of excess weight gain is most effective then during the growing years ■ When fat cells increase in numbers ○ If fat is still abundant, the excess is deposited in organs such as the heart and liver. ■ at that accumulates outside of adipose tissue—called ectopic fat—disrupts normal metabolism and contributes to the development of diseases such as ● heart failure and fatty liver ■ As ectopic fat accumulates, metabolic changes that indicate disease risk—such as insulin resistance—become apparent and chronic inflammation develops. Fat Cell Metabolism ➢ Lipoprotein Lipase (LPL) ○ An enzyme primarily found on the surface of cells lining muscles and adipose tissue ■ As chylomicrons from the intestine and VLDL from the liver pass by, LPL breaks down their cargo of triglycerides, providing fatty acids that muscles may use for energy and adipose tissue may store for later use ➢ People who are obese have more LPL activity in their adipose tissue than others do ○ This high LDL activity makes fat storage efficient ➢ In women ○ Adipose tissue in the breasts, hips, and thighs produces abundant LPL ■ Storing fat in those body sites ➢ In men ○ Adipose tissue in the abdomen produces abundant LPL ➢ This difference in enzymes activity explains why men tend to develop central obesity around the abdomen (becoming apple shape) ○ Women develop lower body fat around the hips and thighs (pear shaped) ○ Sex differences are apparent in the activity iof the enzymes controlling the release and breakdown of fat in various strage sites in the body ■ The release of lower body fat is less active in women than in men ■ The release of upper body fat is similar ➢ The rate of fat breakdown slower in women than in men ○ Women typically have more difficulty losing fat in general from the hips and thighs ■ Enzyme activity also explain why some people who lose weight regain it so easily ➢ After weightloss adipose tissue LPL activity increases promoting fat storage Set Point Theory ➢ Physiological variables such as ○ Blood glucose ○ Blood ph ○ Body temperature ■ Remain stable under a variety of conditions ➢ The hypothalamus and other regulatory centers constantly monitor conditions and direct adjustments to maintain homeostasis and restore the set point. ○ Body weight fluctuates around a set point ■ Shifting only slightly and temporarily under normal regulatory conditions ➢ After weight losses the body slows its metabolism ○ Reduction in the metabolic rate after weight loss is greater than would be expected based on body composition alone. Review ➢ Fat cells develop by increasing in number and size. Preventing obesity depends on maintaining a reasonable number of fat cells. The body regulates its body weight and defends its set point in a complex system that detects signals, integrates information, influences eating behavior, and adjusts energy expenditure. 9.2 Causes of Overweight and Obesity ➢ People accumulate fat because they take in more energy from foods and beverages than they expend on physical activity and metabolic processes. ○ Major contributors to obesity ■ genetics and the environment. Genetics and Epigenetics ➢ Prader Willi Syndrome: genetic disorder characterized by excessive appetite, massive obesity, short stature, often intellectual disability Most cases come from an interplay of many genes ■ more than 300 sites in the human genome are associated with obesity and fat distribution ➢ Identical twins more likely to weigh the same ○ genes interact with the eating and activity patterns that lead to obesity and the metabolic pathways that influence satiety and energy balance ■ Even identical twins with identical genes become different over the years as epigenetic changes accumulate ○ you cannot change the genome you inherit, but you can influence the epigenome. ■ Physical activity can minimize genetic influence on body fat ■ On the other hand , solid fats, added sugars, and physical inactivity can accentuate the genetic influences on obesity. ➢ genetics makes a person more or less likely to gain or lose weight when overeating or undereating. ○ Some people gain more weight than others on comparable energy intakes. ■ Given an extra 1000 calories a day for 100 days, some pairs of identical twins gain less than 10 pounds while others gain up to 30 pounds. ■ Each cell expresses only the genes for the proteins it needs, and each protein performs a unique function. Leptin ➢ Obesity gene called ob ○ Expressed primarily in the adipose tissue and codes for the protein leptin ➢ Acts primary in the hypothalamus to regulate body weight by suppressing appetite and increasIng energy expenditure ○ Leptin promotes a negative energy balance and a decrease in body weight and fatness. ■ Mice with a defective ob gene do not produce leptin and can weigh up to three times as much as healthy weight mice and have five times as much body fat ○ Because leptin is protein it would be destroyed during digestion if given orally; it must be given by injection ■ Fat cells shrink and self destruct (reducing cell numbers) explaining why weight gains are delayed when mice are fed again ➢ Extremely obese children with barely detectable blood levels of leptin have litte appetite control ○ Constantly hungry and eat more than their siblings ○ Given daily injections of leptin these children lose a substantial amount of weight ➢ Many few obese people have leptin deficiencies ○ Leptin levels increase as body fat increases ○ Leptin sensitivity decreases ■ Leptin resistance:condition in which leptin levels increase and leptin sensitivity decreases Ghrelin ➢ Protein that also acts as a hormone primarily in the hypothalamus ○ Secreted mainly by the stomach cells and promotes a positive energy balance and an increase in body weight and fatness ➢ Stimulates appetite and triggers the desire to et ○ ○ ○ ○ ○ ○ Blood levels of ghrelin rise before a meal and decline afterwards ■ Reflect the hunger and satiety that precede and follow eating On avg ghrelin levels are high whenever the body is in negative energy balance as occurs during low kcalorie diets ■ ex.) ghrelin levels are low whenever the body is in positive energy balance as occurs with weight gains A person's mindset also influences ghrelin's response to a meal ■ Young adults were given beverages on two separate occasions—either a beverage labeled as a high-fat, 620-kcalorie “indulgent” milkshake or one labeled as a low-fat, 140-kcalorie “sensible” milkshake. ● Ghrelin rose in anticipation of drinking the indulgent milkshake and declined afterward much more steeply than with the sensible milkshake ● In reality both milkshakes were identical ■ Drinking the sensible milkshake was not as satisfying, despite its having the exact same nutrient contents as the indulgent milkshake. ● The sensible mindset with its relatively flat ghrelin response leaves a person with a heightened appetite. ● These findings suggest there may be a physiological benefit to adopting a psychological mindset of indulgence when eating low-energy-density, healthy foods. Ghrelin promotes sleep ■ Lack of sleep raises the hunger hormone ghrelin and reduces the satiety hormone leptin ■ These hormone changes may explain the association b/w inadequate sleep and increase desire for high calorie foods, energy intake and weight gains Physical activity improves sleep time and quality Uncoupling Proteins ➢ Genes code for proteins involved in energy metabolism ○ May influence the storing or expending of energy with different efficiencies or in different types of fat ➢ Body has different types of adipose tissue and the quantities of each are determined by genes ○ When adipose tissue stores fat for other cells to use for energy ■ Brown adipose tissue releases stored energy as heat ■ Defending against cold & preventing obesity ➢ In coupled reactions Energy released from the breakdown of one compound is used to create a bond in the formation of another compound ■ ex.) when fat is oxidized some of the energy is released in heat and some is captured in the formation of ATP ➢ Metabolism in brown adipose tissue differs ○ Oxidation is uncoupled from ATP formations ■ In uncoupled reactions ● All of the energy is released as heat ● By radiating energy away as heat ○ The body is expanding rather than storing energy ➢ efficient coupling facilitates synthesis reactions, including the making of fat for storage ○ Weight gains or losses may depend on whether the body dissipates the energy from an ice cream sundae as heat or stores it in body fat. ➢ Brown fats heat production is important in newborn infants and in animals exposed to cold weather ○ They have plenty of brown adipose tissue ○ Humans have little brown fat ➢ Brown fat is metabolically active during exposure to cold ○ Activity declines with age and with obesity ○ Overweight people and obese have less brown fat activity than others ➢ White fat cells can undergo process known as browning ○ Take on characteristics of brown fat; mostly in uncoupled proteins ○ Fat cells called brite adipocytes ■ More abundantly than brown fat cells in adults ➢ During exercise, muscle cells release a protein that triggers the transformation of white fat cells into brite fat cells. ○ Among dietary factors that promote brown fat activity or the browning of white fat ■ phytochemicals, omega-3 fatty acids, and vitamin A. ➢ Another factor gaining attention for its influence on the browning of white fat is the GI microbiota. ○ The GI microbiota in people who are obese tend to be limited in diversity and in activity. ○ Some research suggests that pre- and probiotics improve the GI microbiota and prevent weight gain. Environment ➢ Obesity reflects the interactions between genes and environments ○ Obesogenic environment ■ Includes all circumstances that encounter daily that push us toward fatness ➢ The interactions created between genetic and environment created the epigenetics that provide greater understanding of obesity and related diseases ○ Genes can influences eating behaviors ■ Food and activity behaviors influence the genes that regulate body weight ■ Social relationships can influences food and activity choices and the development of obesity Overeating ○ ➢ Diet histories are not always accurate records of actual intakes and people of all sizes commonly misreport their dietary intakes. ○ current intakes may not reflect past eating habits, which led to obesity. ○ People who had a positive energy balance for years and accumulated excess body fat may not currently have a positive energy balance. ■ This reality highlights an important point: the energy-balance equation must consider time. ■ Both present and past eating and activity patterns influence current body weight. ➢ Simply put, large portion sizes promote overconsumption and deliver more kcalories ○ portion sizes of virtually all foods and beverages have increased markedly in the past several decades, most notably at fast-food restaurants ○ but they are now two to eight times larger than standard serving sizes. ○ Fast food is often energy-dense food. ■ The combination of large portions and energy-dense foods is a bad ○ Low-energy-density foods such as fruits and vegetables truly help with weight loss. ➢ Convenience foods are often ultra-processed foods, rich in added sugars and saturated fat, and a major source of energy in many countries around the world ○ In The United States, ultra-processed foods provide almost 60 percent of daily energy in the average diet. ■ people who eat ultra-processed foods consume more energy (about 500 calories a day) and gain more weight than those who primarily eat unprocessed foods ■ In addition to contributing to a higher energy intake and body weight, ultra-processed foods are inadequate in providing nutrients and supporting health ➢ an ultra-processed product is to read the ingredients list ○ typically contains items that are never or rarely used in kitchens (such as interesterified oils and maltodextrin) ○ additives (such as glazing agents and humectants) whose sole function is to make the final product more appealing Physical Inactivity ➢ People are most inactive when watching television, playing video games, and using the computer. ○ The more time people spend in sedentary activities, the more likely they are to be overweight—and to incur the metabolic risk factors of chronic diseases (high blood lipids, high blood pressure, and high blood glucose) ➢ Sedentary activities contribute to weight gain ○ 1.)They require little energy beyond the resting metabolic rate. ○ 2.) they displace time spent in more vigorous activities. ○ 3.)television and Internet advertisements influence food purchases and the urge to eat. ➢ Reducing their food intakes further would incur nutrient deficiencies and jeopardize their health. ➢ People must be physically active if they are to eat enough food to deliver all the nutrients they need without unhealthy weight gain. ○ To prevent weight gain, the DRI suggests an accumulation of 60 minutes of moderately intense physical activities every day plus the less intense activities of daily living. ○ Recommendations to lose weight encourage even greater duration, intensity, and/or frequency of physical activity. Peron migh be obese not because they eat too much but because they move too little ■ nonexercise activity thermogenesis (NEAT)—plays a pivotal role in energy balance and weight management. ● Sitting, laying down, standing 9.3 Problems of Overweight And Obesity ➢ For many, improving eating and activity habits to simply prevent further weight gains will incur some health benefits. ○ Whether a person will benefit from weight loss depends on other health parameters. Health Risks ➢ To prevent or improve these health problems, health care professionals recommend ○ weight loss for people who are obese (BMI ≥30) ○ those who are overweight (BMI 25 to 29.9) ○ with one or more of the following obesity-related risk factors: ■ Hypertension ■ Fatty liver disease ■ Abnormal blood lipids ■ Diabetes or prediabetes ■ Sleep apnea ○ Even modest, sustained weight loss can improve blood lipids, blood glucose, and blood pressure. ○ Greater weight loss may produce greater benefits and reduce the need for medications. Social Consequences ➢ We associated stigma and shame causes additional harm by contributing to behaviors such as ○ binge eating, social isolation, avoidance of health care services, decreased physical activity, and increased weight gain Physiological Problems ➢ Obesity has negative psychological consequences, including ○ Depression, impaired body image, low self-esteem, eating disorders, stress, and poor quality of life. ■ Anxiety and depression, in turn, often lead to emotional eating and weight gain. ○ Ineffective treatment and its associated sense of failure add to a person’s psychological burden ➢ devastating psychological effects of obesity and restrictive dieting perpetuate themselves, quite often leading to a pattern of repeated losses and gains known as weight cycling. ○ Dangerous Interventions ➢ Wise consumers scrutinize fad diets, magic potions, and wonder gizmos with a healthy dose of skepticism. ➢ Of course, some weight-loss programs are better than others in terms of cost, approach, and customer satisfaction. ○ Reputable weight-loss programs explain the risks associated with their plans and provide honest predictions of success. Fad Diets ➢ Popular eating plans that promise quick weight loss. Most severely limit certain food or overemphasize others ○ ex.) never eat potatoes of pasta, or eat cabbage and soup ➢ Some fad diets are hazardous ○ Adverse reactions can be as minor as headaches, nausea, and dizziness or as serious as death Weight Loss products ➢ Some turn to natural herbal products and dietary supplements ○ Containing cannabidiol (CBD OIL) ■ Compound derived from weed plant ○ Dietary supplements do not have to be approved by FDA and manufacturers don't have to test the safety or effectiveness of these products ➢ The FDA has identified hundreds of products that contain undeclared, active pharmaceutical ingredients that can cause serious harms such as seizures and heart attacks ○ Its review of CBD products found unsafe levels of contaminants such as pesticides, heavy metals, and THC (the marijuana compound associated with the “high”). ■ These ingredients are not listed on the labels, so consumers have no way of spotting them Other Gimmicks ➢ Hot baths do not speed up metabolism so that pounds can be lost in hours. ➢ Steam and sauna baths do not melt the fat off the body, although they may dehydrate people so that they lose water weight. ➢ Brushes, sponges, wraps, creams, and massages intended to move, burn, or break up fat do nothing of the kind. Review ➢ The question of whether a person should lose weight depends on many factors: among them are the extent of being overweight, age, health, and genetic susceptibility. Not all obesity will cause disease or shorten life expectancy. Just as there are unhealthy, normal-weight people, there are healthy, overweight people. Some people may risk more in the process of losing weight than in remaining overweight. Fad diets and weight-loss supplements can be as physically and psychologically damaging as excess body weight. 9.4 Aggressive Treatments for Obesity ➢ Clinically severe obesity ○ A AMI of 40+ or a BMI of 35+ with additional medical problems ■ A less preferred term used to describe the same condition is morbid obesity ➢ Someone with clinically severe obesity may need more aggressive treatment options drugs or surgery ○ Drugs appear to be modestly effective and safe ○ Surgery is dramatically effective but can have severe complications for some people Drugs ➢ Many drugs have been approved by the FDA for obesity treatment ○ Should be prescribed to those with medical risks not for cosmetic reasons and related to healthy eating and activity plans ➢ Somer physicians practice off label use ○ Prescribing unapproved furs for weight loss ○ Drugs have been approved for other conditions like seizures that also cause weight loss Surgery ➢ US prevalence of clinically severe obesity (BMI +40) is at 9% ○ Most effective treatment is bariatric surgery ○ May be an option for people with these conditions: ■ Unable to achieve adequate weight loss with diet and exercise ■ BMI ≥40 or BMI ≥35 with obesity-related health problems (such as diabetes or hypertension) ■ No medical or psychological contraindications ■ Understanding of risks and strong motivation to comply with post-surgery instructions ○ More than 200,000 surgeries are performed in the US annually ➢ Surgical procedures effectively limit a person's food intake by reducing the capacity of the stomach ○ Suppresses hunger and alters metabolism by changing hormone secretion ■ Changes in appetite, food preferences, and GI microbiota may also influence weight losses. ● The results are significant: depending on the type of surgery, 20 to 30 percent of the original excess weight remains lost after 10 years. ○ Most people experience dramatic and lasting improvements in their blood glucose, blood lipids, and blood pressure; risks of diabetes, heart attacks, strokes, and cancer are also reduced. ➢ Overall, bariatric surgery provides clear advantages for greater weight loss and long-term survival over nonsurgical options for adults who are obese. ○ Long term safety and effectiveness coincides with the dietary instructions and making nutrition care plans essential in follow up treatment ○ With limited food intake and reduced absorptive surfaces, vitamin and mineral deficiencies are common. Other Medical Procedures ➢ Several endoscopic procedures have been approved for weight loss. ○ One such effective procedure involves the insertion of an intragastric balloon, which occupies space in the stomach, thus enhancing feelings of fullness and diminishing food intake. Another safe and effective procedure uses gastric aspiration to empty the contents of the stomach 20 to 30 minutes after each meal. ■ Compared with drugs and surgery, these endoscopic procedures are less invasive, less expensive, and easily reversible.Footnote ➢ Medical procedure removes some fat deposits by liposuction ○ Reduces body weight by fewer than qo pounds and alter body shape in specific areas Review ➢ People of all sizes may benefit most from improving eating and activity habits. Those with clinically severe obesity and high risks of medical problems may need more aggressive treatment, including drugs or surgery. Such treatments may offer benefits, but also incur some risks. 9.5 Lifestyle Strategies ➢ Successful approaches include healthy eating patterns, physical activities, supportive environments, and psychosocial support. Such interventions can be effective, even when genetics factors are in play Changes, Losses, and Goals ➢ A reasonable weight loss for adults is 5 to 10 percent of body weight over 1 year. ○ For a person weighing 250 pounds, a 10 percent loss is 25 pounds, or about pound a week for the year. ○ Such gradual weight losses are more likely to be maintained than rapid losses. ➢ Modest weight loss can improve blood glucose and reduce the risk of heart disease by lowering blood pressure and blood lipids ○ Especially those with central obesity ○ Improvements in health, physical capabilities, and quality of life become evident with even a 5-percent weight loss ■ parameters such as blood pressure, blood lipids, and vitality are better indicators of success than body weight. Eating Patterns ➢ It helps to embrace healthy foods (such as spinach) instead of focusing on unhealthy foods to avoid (such as french fries). ➢ Creating a healthful eating pattern is the first step. ○ Then there is an indispensable next step: following it for the rest of one’s life. ○ The pursuit of good health requires lifelong lifestyle habits. Be Realistic About Energy Intake ➢ Weight loss diets designed to provide less energy than the person needs to maintain present body weight. ○ If food energy is restricted too severely ■ Dieters may not receive sufficient nutrients ○ Rapid weight loss means excessive loss of lean tissue and rapid weight trains to follow ■ Composition of regained weight is more fat and less lean than the composition of the originally lost weight ○ Restrictive eating may create stress or foster the unhealthy behavior of eating disorders ➢ Energy intake needs to provide nutritional adequacy without excess ○ Between deprivation and complete freedom to eat whatever ○ weight-loss diets should provide about ○