BIOD 121

Low Carbohydrate

Most of these diets have a severe carbohydrate restriction, which causes the body to turn to stored glycogen and protein for energy. This can lead to weight loss but also ketosis, constipation, headaches, and muscle cramps. The weight that is lost is often water weight. Failure usually occurs related to boredom with the diet. Several well-known low carbohydrate diets include the Atkins, South Beach, Zone, and Nutrisystem. Recently there has been more emphasis on the glycemic load. Carbohydrates are limited, but emphasis is placed on low glycemic index foods, such as whole grains, fruits, and vegetables and limiting the high glycemic index foods. While not perfect, it is a more reasonable diet to follow and long-term success has been achieved. Examples of this type of diet include the New Glucose Revolution and the GI Diet.

serving

a specific measurement of food

Underwater weighing

is a very accurate process where an individual is weighed on a scale and then again while under water. The difference between the two measurements (normal vs. underwater) is then used to estimate the total body volume. From this the percentage of lean muscle and body fat can be calculated.

Gastric balloon

is an additional approach for weight loss surgery. A gastric balloon is made out of soft silicone and the deflated form is inserted through your esophagus into the stomach. The procedure takes approximately 30 minutes with no incisions or surgery required. The balloon is then inflated to the size of a grapefruit. The balloon is not permanent and is removed after approximately 6 months. The key to success is that lifestyle changes are being taught and implemented throughout the process and continue after the balloon is removed.

Extremely low-calorie diet

is an approach of consuming only 400-800 calories per day. Often this diet entails a low carbohydrate and high protein diet, often in liquid form. Careful monitoring by a physician is necessary.

Hyperplasia

is an increase in the number of fat cells often occurring during periods of growth, such as adolescence or pregnancy

Energy balance

is defined as a state when one's energy intake is equivalent to the amount of energy expended. In other words, the number of calories ingested from food and beverages must be equal to the number of calories burned through basic body functions plus exercise. Thus, in order to prevent weight gain and maintain an appropriate weight, we must understand the concept of energy balance.

portion

is the amount of food you choose to eat

Nurture

is the environmental factor

Positive energy balance

occurs if more calories (energy) are consumed than expended. There are certain periods when we need to consume more calories than we expend. Examples would include periods of growth, such as pregnancy or periods of childhood and adolescence when growth spurts occur. Over time, however, the excess consumption will lead to weight gain. In fact, by consuming an extra 500 calories a day over what is expended, you could gain one pound in a week. Generally speaking, one pound of fat is equal to 3500 kcal.

There are three components to weight loss and weight maintenance that must be implemented in order to be successful:

(1) control of calories, (2) physical activity, and (3) behavior modification

For some individuals, controlling calories, physical exercise, and behavior modification are not enough to achieve a healthy weight. Individuals with a BMI of >30, or > 27 with co-morbid health risks (referred to as morbid obesity) may require drastic weight loss measures such as

(1) medications, (2) extremely low-calorie diets, and/or (3) surgery. Importantly, all of the above measures must be undertaken under the direction of a physician.

There are a number of fad diets on the market, but most fall under one of four categories:

(1) moderate calorie restriction, (2) carbohydrate focused, (3) low-fat, or (4) novelty.

Gynoid obesity

(lower body) is defined by fat being stored below the waistline, yielding the commonly referred to "pear" body shape (Figure 3.3; right). Lower body obesity is more common in the female form and describes a small waist with much of the fat deposited in the hips and thighs

Android obesity

(upper body) is defined by fat being stored in the abdominal area, yielding the "apple" body shape (Figure 3.3; left). Upper body obesity is common in males and is linked to high blood testosterone levels and an increased risk of diabetes and hypertension. Alcohol consumption, smoking, and a diet with a high glycemic load also contribute to this form of obesity

Behavior modification intervention strategies

1. Chain breaking: Breaking the tie that connects two or more behaviors that encourage overeating. For example, instead of munching on snacks while watching TV, limit yourself to eating only in the kitchen while seated at the table. 2. Stimulus Control: Finding ways to avoid temptation when we are hungry or bored. For example, not buying convenience foods you are fond of or limiting yourself to one small piece of chocolate daily. 3. Cognitive restructuring: Changing your frame of mind regarding food. Rather than turning to food when you are stressed, you decide to exercise instead. After the exercise, if you still want to eat something, allow yourself a small portion of that food. 4. Contingency management: Preparing for situations that might trigger over eating such as a party or donuts at the office. If you have a board meeting to attend and you know the boss will be bringing in donuts, offer to bake a low-fat coffee cake as an alternative for those trying to watch their weight. 5. Self-Monitoring: Keep a diary for several days, recording what you eat, when you eat it, how you felt and where you were when you ate. This helps to reveal patterns that may be negatively affecting your weight loss efforts. Behavior modification is extremely important in understanding our eating habits and helping us to make changes to meet our weight loss goals. In addition to the National Heart, Lung, and Blood Institute website

Set point theory

Another theory to support the role of genetics in weight maintenance is called the set point theory. states that each of us has a genetically predetermined body weight and that the body will resist change beyond this set point. This set weight is a weight that was not difficult to maintain on your part.

the two major components of energy expenditure are the basal metabolic rate and physical activity.

BMR x PA

Low Fat:

Diet eliminates animal protein sources and oils. The focus is on fruit, vegetables, and grains. This can be a very healthful way of eating but with fat restricted to < 20% of calorie intake, it can get very monotonous. Improvements in cholesterol and blood pressure are often observed if people can follow this approach. Examples include: The Ornish or Pritikin diets, T-Factor Diet, and Eat More Weigh Less.

Novelty:

Diet focuses on a gimmick. They promote certain foods or types of foods as having special weight loss qualities. There is no scientific evidence to back up any claims. Examples include The Cabbage Soup Diet, The Beverly Hills Diet, and The Cookie Diet. The bottom line with this type of diet: The weight loss results from lack of calories, not from the foods that are promoted. They are not nutritionally balanced and may lead to malnutrition if followed for long periods of time.

Moderate calorie restriction

Diet limits calories to 1200-1800 per day. If the plan includes a wide variety of foods from all food groups and encourages exercise, it may be an acceptable weight loss plan. Examples of this type of diet include: Weight Watchers, Jenny Craig, Dr. Phil's Ultimate Weight Solution, and Dieting for Dummies

Waist circumference can also be used as an indicator of obesity:

In males, a waist circumference greater than 40 inches and in females greater than 35 inches results in a diagnosis of obesity. A final method of using anthropometrics to determine if someone is overweight is the waist-to-hip ratio. To do this properly, first measure around the waist (at the level of the belly button) while relaxed. Next, measure the hips around the largest part of the buttocks. Finally, divide the waist measurement by the hip measurement. The desired ratio in males is <0.9 and in females < 0.8. Exceeding the respective values would be indicative of a health risk

BMR Calculations:

Male BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age) Female BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age) Once the BMR is calculated, the activity level can then be added: Physical Activity (PA) Estimates 1.2 = little to no exercise 1.375 = light exercise 1-3 days per week 1.55 = moderate exercise 3-5 days per week 1.725 = hard exercise 6-7 days per week 1.9 = hard daily exercise/job To determine individual energy requirements, multiply the BMR x PA estimates (relative to the appropriate activity level). The resulting value is the number of calories required to expend daily in order to maintain their current weight.

Physical activity

accounts for 15-40% of our energy expenditure. A number of factors, such as body size, fitness level, and the actual activity, determine how many calories are expended. Low physical activity and a "couch potato" mentality often lead to weight gain. Previous generations expended many more calories than we do today as jobs were physically demanding. In contrast, modern conveniences do much of the work for us. As a result, we live a much more sedentary lifestyle and must intentionally choose to be active.

Medications

currently available to treat weight loss are classified into one of three classes: amphetamines, appetite reduction drugs, and fat absorption inhibitors. The amphetamines stimulate the central nervous system and burn calories. These are only used short term as abuse or even a dependency can be developed. In terms of appetite reduction, Meridia is an FDA approved medication used to decreases hunger sensations. The moderate reduction in appetite is helpful to people who eat a fairly healthy diet but consume excess quantities. To decrease fat absorption, the FDA approved Orlistat (also known as Xenical). Orlistat inhibits lipase enzymes from breaking down fat in the small intestine. The result is approximately a third of the dietary fat taken in (ingestion) is not absorbed. The fat then passes out of the body in the feces. Side effects include gas, bloating, and diarrhea if excess fat is consumed while taking this medication. A low dose form of Orlistat, Alli, is available over the counter.

Social support

from family, friends, social programs, and/or professional help is complementary to behavior modification and perhaps equally important for weight loss and maintenance. Family and friends can have a positive or negative impact. Studies show eating out at restaurants with overweight people puts you at risk for overindulging. It is important to make sure family and friends understand why you desire to lose weight and that you seek their encouragement and support. Social programs may include hospitals, community colleges, and restaurants as they can be good resources for healthy cooking classes. Strength training programs offered through Coop extension programs are also examples of social programs. Professional help would include physicians, exercise physiologists, and registered dietitians. These professions have been trained to help clients make wise food and exercises choices. Reliable weight loss programs are also available and include TOPS (take off pounds sensibly), Weight Watchers, Nutra System, and Jenny Craig. The more knowledge and support you have the greater your success at weight loss and long-term maintenance.

Body Mass Index (BMI)

is an improved measure of body fat relative to one's height and weight. As a more recent replacement to the height-to-weight tables, the BMI can be used to categorize an individual as being underweight, at a healthy weight, overweight, or obese. BMI is calculated by dividing one's weight (in kilograms) by the square of one's height (in meters). BMI = weight (kg) / height2 (meters) Although the BMI is an improvement from the height-to-weight tables, in certain populations the BMI is not as accurate. Such populations include children, teens, pregnant or breast-feeding moms, short statute adults, very muscular individuals, and the elderly. For this reason, separate BMI tables are available for children and pregnant women, etc. As shown in Figure 3.2, a calculated BMI of < 18.5 would be considered underweight (purple), while a BMI > 30 is considered obese (blue). In between these two extremes falls the normal or healthy BMI with values between 18.6 and 25 (green) and the overweight BMI with values between 25 and 30 (yellow). Taken together, a BMI table is a quick tool to determine an individual's healthy weight for height.

Hypertrophy

is an increase in the size of fat cells, most often seen in periods of low growth and maintenance, such as throughout adulthood. Occur naturally throughout growth period, but when adults we don't want to increase the # of fat cells in body

Fat cell development

is another biological factor related to our weight. Once a fat cell is formed, it will always be present. Further, our bodies are predisposed to want to fill the fat cells. While it is possible to shrink the size of fat cells, we cannot get rid of fat cells through dieting. Sex, age, race, and ethnicity also play key roles in our body composition.

Bioelectrical impedance

is based on the principle that water conducts electricity and fat resists electricity. As muscle is primarily composed of water, an instrument with electrodes is connected to the body and a painless low energy electric current is sent through the body. Since fat resists electricity, higher levels of resistance indicate a higher percentage of body fat.

Underweight

is defined as a BMI of < 18.5. A low body weight can be often related to either genetics (you simply inherit a small frame size) or to a disease state. In most cases, the low weight is due to a GI disorder such as irritable bowel disease, where nutrients as well as calories pass through your GI tract without being absorbed properly. Additional diseases states such as AIDS or cancer can also cause an individual to be underweight. Apart from disease, additional causes for being underweight can range from an eating disorder to excessive dieting and exercise. For underweight individuals, sometimes gaining weight can be as difficult as losing weight. As with losing weight, the same principles can be applied to gain weight: controlling calories, physical activity, and behavior modification. Controlling calories is now done in terms of increasing calories, exercise is now used to build muscle mass, and appropriate behavior modifications are used to aid in replenishing body mass. Suggestions to increase weight include: adding healthy snacks several times daily, drinking beverages that are nutritious as well as a good calorie source, adding healthy fats to meals, and limiting fluid consumption to delay satiety. Just as there are risks to being overweight there are also risks related to being underweight. In females, loss of too much body fat will lead to cessation of the menstrual period. Once this occurs it can have long term health effects, including loss of bone mass, which places even young women at risk for fractures. Low body weight can also adversely affect your immune system, causing complications from surgery or delayed wound healing from an illness. However, if the low body weight is due to genetics and the person is otherwise healthy, there is little need to worry.

Basal metabolic rate (BMR)

is defined as the number of calories used by the body while in a fasting state and accounts for approximately 60-70% of energy expenditure. In general, males require 1 kcal/kg/hour and females require 0.9 kcal/kg/hour to support the functions of various organs and to stay alive. The BMR varies per person based on a number of factors such as: gender, lean body mass, body size, temperature, age, nervous system activity, levels of caffeine intake, and tobacco use (smoking). If someone is trying to lose weight and restricts their calorie intake too much, their BMR will decline. This is the body's safety mechanism to prevent starvation. As we age our BMR declines by 1-2% per decade. Thus, if one fails to make changes in diet or activity levels from one decade to the next, a slow weight gain will be the result—this is why people in their 40s and 50s will often complain about gaining weight and how it has become difficult to lose. Calories that we burn to sustain life 60-70% of total energy expenditure for the day Males have higher BMR than females Muscular (higher BMR)

Surgery

is often the last resort when medications and diets fail. Bariatrics is the branch of medicine that focuses on the cause, prevention, and treatment of obesity. Currently, several bariatric surgeries are available in the treatment of severe obesity. Gastric banding is a restrictive procedure where the opening from the esophagus to the stomach is restricted using a gastric band, forming a small pouch in the stomach (Figure 3.5). The band can be inflated or deflated to control the amount of food a person can consume and still be comfortable.

Thermogenesis

is the ability to regulate body temperature and activities such as fidgeting, maintaining body posture, and shivering. The amount of energy burned through thermogenesis is very small. Recently scientists have begun to study the link between brown adipose (fat) tissue and weight maintenance. Brown adipose tissue is found in infants below the collar bone. The brown fat metabolizes the energy yielding nutrients, which results in heat production to be used by the body. Most adults have little brown fat, but lean adults have been found to have higher levels than their heavier counterparts. Studies are underway to see how this knowledge could be used to benefit those that struggle with being overweight.

Thermic effect of food (TEF)

is the energy used for digestion and absorption of food and accounts for approximately 10% of the calories expended. Larger meals and meals higher in protein result in a higher TEF. Small amount

Nature

is the genetic factor

Dual Energy X-ray Absorptiometry (DEXA)

is the most accurate measure of body fat composition as well as bone mass. An instrument that emits small doses of radiation determines the amount of fat, lean tissue, and bone in an individual. However, it is very expensive and rarely used.

Label reading

is the process of comparing labels on similar products in terms of serving size, number of calories per serving, and the amount of fat per serving.

Physical activity

is the second key to weight loss and maintenance. Being physically active does more for you than just burn calories. Physical activity can decrease your stress level, improve your mood, increase productivity, maintain bone health, and increase lean body mass, which in turns leads to more efficient use of calories even at rest. Regular activity is the key to good health and positive results. Current recommendations are for 60-90 minutes of activity per day, as well as 10,000 steps. Although it was once thought any activity had to be continuous for 60 minutes to be beneficial, this is now known not to be the case—small increments of activity throughout the day that add up to 60 minutes can be just as beneficial. In addition to cardio activities, adding resistance exercises and stretches daily has been shown to be beneficial. Resistance exercises builds muscle and lean body mass. Although changes in the number on the scale may not be readily evident, resistance and stretching exercises tone the body. At the same time, bone mass is being preserving which will help fight osteoporosis later in life. As a whole, taking care of your body now through physical exercise will help to ensure a smooth transition later into the last decades of life.

Behavior modification

is the third key to weight loss and maintenance and describes how certain factors (or behaviors) can prevent us from reaching our weight loss goals. Clearly defining such factors and learning how to manage them are important to a successful outcome. After all, most people find it very difficult to maintain their weight loss. The majority of successful losers end up regaining the weight they lost within five years. This is why behavior modification strategies are so important—they provide strategies that can be followed long term regardless of what stage of life you are in. The following are some of the intervention strategies used to address these problem areas.

"thrifty" metabolism

meaning fewer calories than normal are used to maintain body function. Someone with a thrifty metabolism is thus prone to weight gain as their unusually low basal metabolic rate results in fewer calories being burned, which in turn encourages the generation and storage of fat.

Direct calorimetry

measures the amount of heat given off by the body. An insulated chamber surrounded by a thin layer of water is used to measure the amount of heat emitted by the subject in the chamber. This method is used infrequently due to the expense and complexity of the procedure.

Negative energy balance

occurs if fewer calories are consumed than calories expended. At times, an individual may be unintentionally in negative energy balance, such as during an illness or trauma as they would negatively affect appetite and intake. In other cases, an extremely high amount of energy is required for healing, such as someone who has suffered a major burn injury. However, for most of the population, being in negative energy balance is an intentional act. Calories are limited and/or exercise is increased with the goal of weight loss. Good for losing weight Not good for someone with a chronic disease, trauma, or eating disorder

fad diet

often emphasizes one food group and includes many gimmicks. Regardless if you are overweight, underweight, or at a healthy weight, there is a high probability that you have heard of, if not tried, a fad diet. You find them advertised everywhere: the Internet, newspapers, radios, magazines, books, and even celebrity endorsements. In all likelihood, you can lose weight following a fad diet. However, it is important to consider if the apparent weight loss is because of the fad diet or simply the result of limiting calories throughout the day. Fad diets share some similar characteristics: 1. They promote quick weight loss. While you may shed the weight quickly, it is water weight, not fat, that is being lost. 2. They use celebrities or actors impersonating medical personnel to sell their product. 3. Food selections are limited and often you are encouraged to avoid one or more food groups. 4. They are expensive and often encourage you to buy nutritional supplements. 5. They cure all. Not only do you lose weight but you will have more energy, a better sex life, and decreased stress. 6. More importantly, they do not recognize the role of exercise or behavior modifications in weight loss.

Height-to-weight tables

often published by insurance companies, were used in an attempt to link longevity to a person's weight as based on their height (Figure 3.1). However, these tables were used for the general population but did not take into account individual differences. Today, the term "healthy weight" is used, rather than ideal or desirable. Each person should consider their weight history, where fat is distributed in the body, family health history, current weight, and activity status in order to determine their own healthy weight. Remember, the number on the scale is just a general guideline. The real goal is to be healthy and fit.

Controlling calories

or simply regulating the number of calories you consume daily is not based on a magical formula. To be successful, you first have to change the way you think about weight loss. The key is to think of calorie control in terms of lifestyle changes (in relation to food and dietary intake) that can be followed for the remainder of one's life. A good goal is to lose 1-2 pounds per week. While seemingly an insignificant loss, by losing weight slowly over time, the likelihood of success in both weight loss and maintenance increases.

Gastroplasty

or stomach stapling works by reducing the stomach capacity and bypassing a small portion of the small intestine (Figure 3.6). The stomach can now only hold 30 milliliters or the volume of 1 egg. The majority of individuals who undergo this form of surgery lose approximately 50% of their weight. Post-op individuals feel full quickly and learn not to over eat as abdominal discomfort and vomiting will occur. While this approach has been proven to be effective for weight loss, it must be performed under a physician's supervision with behavior modification techniques encouraged. Extensive counseling and a patient's history is often reviewed prior to surgery approval. Health risks include bleeding, clots, hernias, infection, nutrient deficiencies, and increased risk of death. The procedure is costly and may involve an additional surgery in order to remove excess skin once weight loss is achieved. The client needs to thoroughly understand the risks associated with the procedure and be willing to make lifestyle changes, including adding exercise to their daily activities.

Anthropometrics

the science of measuring the proportions and size of the body, offers a more practical method to determine body fat composition. Skinfold measures using a caliper, one important type of anthropometric measure, can be done quickly and fairly accurately—if the person doing the measurements is trained properly. By measuring the fat layer just under the skin at several locations, the percent body fat can be calculated.

Indirect calorimetry

uses oxygen intake and carbon dioxide output, along with scientific formulas, to measure energy expended. It is convenient, fairly cheap, easy, and very portable.