Nutrition Portage Learning - Module 3 (Energy and Balance)

Calculation Example:

The energy requirements for a female who is 30 years old, 5 feet 5 inches, 140 pounds with light activity is calculated below. -> BMR = 655 + (4.35 x 140) + (4.7 x 65) - (4.7 x 30) -> BMR = 655 + (609) + (305.5) - (141) -> BMR = 1,569.5 - 141 = 1,428.5 -> BMR x PA estimates = 1,428.5 x 1.375 = 1,964 calories daily Thus, the above female would need to burn 1,964 calories a day (24 hours) in order to maintain her current weight.

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.

Bioelectrical impedance

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.

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 (ex. period of growth [pregnancy/child development]). Over time the excess consumption leads to wt gain, consuming an extra 500 calories a day over what is expended, you could gain one pound in a week. (1 lb of fat = 3500 kcal)

For most adults, the excess calorie consumption eventually leads to an increase in body fat. Fat is stored in adipose cells, which are often categorized by 2 distinct stages:

(1) Hyperplasia is an increase in the number of fat cells often occurring during periods of growth, such as adolescence or pregnancy. (2) Hypertrophy is an increase in the size of fat cells, most often seen in periods of low growth and maintenance, such as throughout adulthood.

Three Keys to Weight Loss and Weight Maintenance

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

Height-to-weight tables

(often published by insurance companies) - used in an attempt to link longevity to a person's wt as based on their height 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/desirable. Each person should consider their wt hx, where fat is distributed in the body, FMHx, current wt, and activity status in order to determine their own healthy wt. - Remember, the number on the scale is just a general guideline. The real goal is to be healthy and fit.

When dxed with overweight/obesity, one must take into account the % and distribution of fat in the body and be aware of the health problems associated with excess body fat.

- Males: between 8% - 24% body fat - Females: between 21% - 35% body fat. -- Females require higher levels of fat for reproduction. - Levels > 24% for males and 35% for females are considered an indicator of obesity. There are several methods that can be used to determine a person's body fat content.

Activity Level

- Sedentary - No exercise - Low Activity - exercises the equivalent of walking 2 miles per day at 3-4 mph - Active - exercises the equivalent of walking 7 miles per day - Very Active - exercises the equivalent of walking 17 miles per day

Body Mass Index (BMI)

- 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). - In certain populations the BMI is not as accurate (such as children, teens, pregnant or breast-feeding moms, short stature adults, very muscular individuals, and the elderly). - separate BMI tables are available for children and pregnant women, etc. - BMI of < 18.5 would be considered underweight (purple), - BMI > 30 is considered obese (blue). - normal/healthy BMI is between 18.5 and 24.9(green) - 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.

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:

Where fat is located in the body can be directly linked to health risks.

-- Males: excess fat stored within abdominal tissues interferes with the livers ability to use insulin (resistance). Fat cells also produce substances that, when expressed in excess, cause increased blood clotting, blood vessel constriction, and inflammation, which leads to an increased risk for hypertension, cardiovascular disease, and type 2 diabetes. -- Females: the fat around the hips and thighs is less likely to cause health issues, but it is very difficult to shed. After menopause, the shift in hormones results in an increased risk of upper body obesity. A women's risk for cardiovascular disease, hypertension, and diabetes increases with this change.

waist circumference can also be used to indicated obesity.

-- Males: waist circumference > 40" = obesity -- Females > 35" = obesity.

Understand the five important strategies in behavior modification.

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.

Be prepared to identify a fad diet and explain why it does not provide those who use it with good chances at long term success.

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.

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.

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.

Fad Diet

A 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.

On the National Heart Lung and Blood Institutes website (www.nhlbi.nih.govLinks to an external site.), you can calculate your BMI using a BMI calculator. This calculator is a quick method to determine your BMI in addition to the BMI tables.

Another helpful website, www.bmi-calculator.netLinks to an external site., can be used to calculate one's BMR, BMI, % body fat, ideal weight, ideal body weight range, waist-to-hip ratio, and calories burned. This site is a good tool to get a picture of one's overall health and fitness.

behavior modification

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.

Body Composition

Both amount and location of body fat is important. Fat is stored in the upper and lower body and its location can have an impact of health. -- Android obesity (upper body): defined by fat being stored in the abdominal area, yielding the "apple" body shape. -- Upper body obesity: common in males and is linked to low testosterone levels and an increased risk of diabetes and HTN. ETOH consumption, smoking, and a diet with a high glycemic load also contribute to this form of obesity. -- 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.

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.

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.

Although being overweight or obese is a health risk, being underweight can also be a cause for concern. 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.

Obesity has become a global epidemic. With the growing evidence that our children are heavier now than in any other decade, there is an increased need to develop public health strategieterm-35s that focus on children and adolescents. Health care costs will soar as the current population ages and health conditions related to obesity become more prevalent.

Current trends, rates, and statistics for the US population can be found on the CDC websiteLinks to an external site.. Despite research and intervention efforts, the percentage of the population who are overweight or obese is too high. While weight loss is not easy, the focus for adults should be a slow weight loss, decreased calorie intake, adequate nutrient intake, and increased physical activity. Once achieved, the long-term goal should become the maintenance of a healthy weight

Be familiar with the terminology used to discuss Energy Balance

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.

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.

Gastric balloon

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.

Gastroplasty

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.

Be familiar with medical procedures used in rare cases for those who need extreme measures to lose weight.

Gastroplasty or stomach stapling works by reducing the stomach capacity and bypassing a small portion of the small intestine. 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. 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

EER Calculations

In addition, other formulas can be used to estimate EER. Here is an example of a different formula. -> Males: EER = 662 - (9.53 x AGE) + PA x (15.91 x WT + 539.6 x HT) -> Females: EER = 354 - (6.91 x AGE) + PA x (9.36 x WT + 726 x HT) -> PA = activity level The Height and weight must be converted to metric measures. Conversion: -> WT = lbs x 1 kg/2.2 lbs = kg -> HT = in x 1 m/ 39.37 in = m First, we must convert weight from pounds to kg and height from feet and inches to meters.

Controlling Calories or simply regulating the number of calories you consume daily is not based on a magical formula.

In order to be successful one must change the way they think about weight loss. Think of calorie control as a lifestyle change in relation to food and dietary intake. A good goal in to lose 1-2 lbs per 1 wk --- losing wt slowly over time increases likelihood of success. * Note: People associate dieting with negative thought of starvation, limiting food, denying oneself of enjoyable foods, and a quick fix. --- Consider the scenario of someone who decided to go on a diet to lose 10 pounds before a big event, such as a class reunion or wedding. The diet is short term, and there is a single goal, weight loss to look good in their clothes and make a positive impression. Although the weight might be lost, often times the diet is ultimately a failure long term as it can't be sustained, and the weight is eventually regained.

Determining Energy Needs

In order to maintain a healthy weight, it is first necessary to understand how many calories your body requires on a daily basis. The amount of energy used can be measured both directly and indirectly.

Serving

It is important to recognize that there is a difference between portion size and serving size. A serving is a specific measurement of food. As such, the number of servings per container are located on the Nutrition Facts label to help consumers make wise food choices. When at home, it is often helpful to use measuring cups and a scale to help with portion control. Without measuring, it is very difficult to visualize what a cup looks like. When controlling calories, a common strategy is also to limit high-fat foods. While decreasing your total intake of fat can have a positive impact on your waistline and health, food labels can be deceiving. Although food manufacturers have marketed low-fat and fat-free products for several years now, in many products, the calorie difference between low-fat and its regular counterpart can be marginal. To make up for the lack of fat, extra sugar or salt may be added to improve the taste of the product. After all, when it comes to the enjoyment of food, taste is a major factor. Additionally, the lack of fat or simply the knowledge that the product is lower in calories, may lead you to actually eat more of a low-fat product. The end result is often the consumption of more calories than if you had just ingested the regular product initially. Healthy Tip: Drinks can also contain a large number of calories. However, after drinking calorie laden beverages, you do not get the same feeling of satiety you would with solid foods. The expert advice: Limit drinks loaded with sugar and choose no-calorie or low-sugar beverages to help with weight control.

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.

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, Phentermine is a FDA approved medication used to decrease hunger sensations. The moderate reduction in appetite is helpful for individuals 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. 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. 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.

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.

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. 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. 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.

Be familiar with genetic (nature) and environmental (nurture) influences on a person's weight.

Nature is the genetic factor, while nurture is the environmental factor. If a child has normal weight parents, that child has a 10% chance of being obese. If, however, one parent is obese, the percentage increases to 40%. If both parents are obese the chances of their children also being obese jumps to 80%.

environmental influences (nurture) may also affect our ability to control our weight.

Over the years, we have witnessed significant changes as modern appliances have made our daily activities less strenuous. Most of us no longer have jobs that involve manual labor, and housework, such as washing clothes and dishes, takes little more than a push of a button. As our lifestyle has become more sedentary, our waistlines have become thicker. In addition to inactivity, there are many other environmental factors that affect our weight: socioeconomic status, friends and family, cultural and ethnic influences, availability of high fat foods, excessive TV viewing, lack of sleep, emotional eating, stress, fast food, and smoking cessation. In other words, our lifestyle in terms of physical activity and physiological factors clearly has an impact on our body size and fat composition.

Physical Activity

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. Healthy Tip: In order to ensure success, choose enjoyable activities and vary them to prevent boredom. Always be looking for ways to add physical activity to your day such as walking to a colleague's office to discuss business rather than sending an email, using the restroom one floor below you and taking the stairs instead of the elevator to get there, or parking at a spot away from the entrance to the mall to add extra steps to your trip. With a little planning and imagination, implementing daily exercise opportunities can be very easy.

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.

energy expenditure

Remember our sole source of energy intake is from food and beverages which are easy to obtain due to the structure of our society however these choices tend to be high in fat, calories, and sodium. consumption of a Snickers bar = 14 grams of fat, 35 grams of carbohydrates, and 4 grams of protein, providing 282 calories. *Reminder: Carbohydrates and protein each yield 4 kcal/gram, fats yield 9 kcal/gram, and alcohol yields 7 kcal/gram. To prevent wt gain one would need to expend 282 calories worth of energy (can happen naturally and intentionally). - Energy can be expended naturally via basal metabolism, the thermic effect of food thermogenesis as well as intentionally through physical activity. Combo of all these components determines the # of calories that are burned or expended on a daily basis. The 2 major components of energy expenditure are the basal metabolic rate and physical activity.

Self-Monitoring:

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.

Social Support

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.

In addition to reading food labels, keeping food records and measuring portion sizes can also be helpful.

Studies have found that people who record everything they eat in a journal are more successful at weight loss and maintenance.

The daily standards of calorie control for females and males is no less than 1200 and 1500 calories.

Studies have shown lowering the calorie intake below these set points actually makes it difficult for an individual to meet their required nutrient needs. In fact, larger people and very active people may require more calories.

In contrast to fad diets, there are several healthy alternatives that may be recommended to help with weight control and disease prevention. The Mediterranean Diet and the DASH Diet are examples.

The Mediterranean diet is a heart healthy eating plan composed of vegetables, fruits, whole grains, beans, nuts and seeds and olive oil. Moderate amounts of dairy, eggs, poultry and seafood may be included; red meat is seldom consumed in this style of eating. The DASH Diet, Dietary Approach to Stop Hypertension, is an eating style to treat or prevent high blood pressure (hypertension). The focus is on high consumption of vegetables, fruits and low-fat dairy foods. Moderate intake of whole grains, fish, poultry and nuts is also encouraged. This dietary approach limits one's sodium intake to <2300 mg per day. Both of these eating patterns encourage a variety of nutrient dense foods that will help prevent chronic disease.

Approaches for Determining Healthy Body Standards

The MyPlate.gov website provides a simple tool to calculate energy needs based on age, gender, and activity level. Once you have determined your energy needs for your current weight and age, you can then start to determine if you are at a healthy weight. In the past, the terms "ideal" or "desirable" were used when referring to weight based on a person's height.

Underwater weighing

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.

Physical activity

accounts for 15-40% of our energy expenditure. - factors such as body size, fitness level, and the actual activity, determine how many calories are expended. - Low physical activity often leads 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.

Fat cell development

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.

Why does it seem that some people can eat constantly and remain thin, while others just look at food and gain weight?

both nature and nurture play a part in determining our body shape. Nature is the genetic factor, while nurture is the environmental factor. RESEARCH: Studies have been done on identical twins that were separated at birth. Years later they exhibited similar body types in relation to weight and fat distribution. The genes they inherited seemed to be the determining factor versus the environment they were raised in. As genes account for 70% of an individual's body weight, we thus inherit specific body types. If a child has normal weight parents, that child has a 10% chance of being obese. If, however, one parent is obese, the percentage increases to 40%. If both parents are obese the chances of their children also being obese jumps to 80%.

Energy Balance

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.

Basal metabolic rate (BMR)

is defined as the # of calories used by the body while in a fasting state and accounts for approximately 60-70% of energy expenditure. - males require 1 kcal/kg/hr and females require 0.9 kcal/kg/hr to support the functions of various organs and to stay alive. - 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). - BMR decreased when over restricting calorie intake (to prevent starvation) - With 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 wt gain will be the result—this is why people in their 40s and 50s will often complain about gained weight and how it has become difficult to lose.

"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.

Portion

portion is the amount of food you choose to eat. However, we also tend to overestimate portion sizes. It is often difficult to envision what a half cup serving looks like without actually measuring it. Portion sizes are also commonly distorted by the notion that bigger is better. Restaurant portion sizes have increased to attract customers, while drink sizes at fast food restaurants and convenience stores have likewise followed suit. Thus, a portion could be greater than or less than the standard amount a person would consume. The National Heart, Lung, and Blood institute website provides a Portion Distortion QuizLinks to an external site. that helps summarize the relation between large portion sizes and excess weight. For example, 20 years ago an average bagel was 3 inches in diameter and provided 140 calories. Today's bagel is 6 inches in diameter and provides 350 calories...a full 210 calories extra! In order to burn off the extra 210 calories, a 130-pound person would need to rake leaves for 50 minutes. For additional help in calorie counting, the MyPlate Tracker and Menu PlannerLinks to an external site. can personalize your goals for reducing calories and making healthy eating changes.

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. Studies have been conducted where a test subject is fed large quantities of calories while in a controlled environment. The result of course is weight gain. After the calories are decreased to appropriate amounts for the individual, the subject's weight will return to his set point. However, it does appear that it is easier to gain weight than to lose weight, and the set point may change as we age. This process is not well understood but is related to various hormones and enzymes. One hormone in particular is leptin, and studies are being conducted to determine its exact role in weight regulation.

Thermogenesis

the ability to regulate body temperature and activities such as fidgeting, maintaining body posture, and shivering. - amount of energy burned through thermogenesis is very small. - Scientists have begun to study the link between brown adipose (fat) tissue and wt 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)

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.

Dual Energy X-ray Absorptiometry (DEXA)

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

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. When looking at labels and comparing products, remember that calories are important, regardless of whether they come from fat, carbohydrates, or protein. For example, compare the labels shown in Figure 3.4. The first has 238 calories and the other 190 calories. The first is also slightly higher in fat and carbohydrate content. Therefore, the second option would be the healthier choice.

Anthropometrics

the science of measuring the proportions and size of the body, offers a more practical method to determine body fat composition. Skin fold 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.