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Understanding Weight Loss and Weight Loss Maintenance in Obesity Treatment

a. Weight loss requires a state of negative energy balance (intake < expenditure).
i. Most individuals are able to achieve negative energy balance through caloric restriction.

b. However, negative energy balance cannot be permanently maintained, as the body adapts to caloric restriction by lowering energy expenditure.
i. Therefore, most weight loss achieved through diet and exercise occurs during the initial 3 to 6 months.

c. In contrast, weight loss maintenance requires achieving a lifestyle that allows maintenance of energy balance (intake = expenditure) at the reduced body weight.
i. This energy balance must be maintained indefinitely to prevent weight gain.

d. The achievement of energy balance over the long term requires filling the “energy gap” created by initial weight loss (that is, the difference between the individual’s previous and current total 24 hour energy expenditure).
i. The energy gap can be filled through lower calorie intake, greater physical activity, or a combination of the two


The achievement of energy balance over the long term requires filling the “energy gap” created by initial weight loss

a. The energy gap can be filled through lower calorie intake, greater physical activity, or a combination of the two.
i. This energy gap is commonly in the range of several hundred calories per day.

b. The achievement of energy balance during weight loss maintenance is made challenging by the fact that 24 hour energy expenditure goes down more than would be predicted by weight loss alone.

c. Stated another way, the body appears to try to defend its higher weight. This fact accounts partly for the high frequency of weight regain among individuals who have successfully lost weight.


Important Components for a Weight Loss Program

a. To achieve weight loss, the patient must create a state of negative energy balance, where energy intake is less than energy expenditure.

b. The most practical way to achieve negative energy balance is by reducing food intake.
i. A key element of a weight loss diet is the use of moderate caloric reduction to achieve a gradual weight loss.

c. Moderate calorie restriction is defined as a daily calorie deficit of 500-1000 calories per day, equivalent to 20-40% of the calorie requirement for an individual that is consuming 2500 calories per day.
i. Most individuals can achieve this degree of energy deficit for a period of several months without great difficulty.


There are many ways to create a negative energy balance with food intake.

a. Patients can use one of the popular diets on their own, structured meal plans such as meal replacements, or commercial weight loss programs.

b. With all diet plans, self-monitoring of food intake is a critical component that is highly predictive of success in weight loss. Patients ideally should count calories as well as grams of fat and carbohydrate.

c. A deficit of 500-1000 calories per day is recommended and should lead to a weight loss of approximately 1-2 pounds per week at the beginning (weight loss will slow down as the individual approaches energy balance).


The target calorie goal is based on the patient’s starting weight.

a. A calorie target of 1200 to 1500 calories per day is generally appropriate for individuals that weight less than 250 pounds, and a target of 1500 to 1800 calories per day is generally appropriate for individuals that weigh 250 pounds or more.

b. It is important to keep in mind that persons with obesity underestimate their calorie intake, in one study by an average of 40%, and similarly overestimate the number of calories burned with physical activity.

c. Very low calorie diets (less than 800-1000 calories per day, or less than 50% of an individual’s calorie requirement) produce more rapid weight loss in the short term but are more expensive because of the requirement for medical monitoring, and are equivalent over the longer term.

d. Also, for most individuals, slower weight loss leads to a relatively greater maintenance of lean body mass


Weight Bias

a. Bias against individuals with obesity has been well documented among all types of health care professionals (physicians, medical students, nurses, dietitians), including individuals whose primary job is treatment of obesity.

b. Weight bias also has been demonstrated among patients with obesity. It is important to be conscious of one’s own biases and to minimize the effect of bias on the therapeutic relationship.

c. A reasonable measure of whether the provider has successfully overcome bias, or at least minimized the impact of bias, is whether the patient feels empowered after the encounter (e.g., are goals set, does the patient have self-efficacy).

d. Patients generally do not like the term obesity, even though it is clinically correct (and should be used in coding).
i. Rather, the term weight is most preferred.


Patients benefit from goals that are specific, concrete, measurable, and achievable.

a. First steps
o Don’t drink calories: cut out sugar-sweetened drinks
o Increase servings of fruit and vegetables, especially vegetables
o Avoid skipping entire meals if possible, if skipping a meal skip dinner
o Move eating to earlier in the day when metabolism is higher
o Reduce portion sizes of all foods by 25-33%
o Slow the pace of eating (take at least 20 minutes to eat a meal)

b. More aggressive
o Purchase a self-help diet book (one validated with scientific research) and follow the eating plan
o Use a structured meal plan, such as a meal replacement approach
o Join a commercial weight loss program or a university-based program
o High intensity programs are recommended in the 2013 obesity treatment guidelines (AHA/ACC/TOS) = at least 14 visits/contacts over 6 months
o With all of the above, self-monitoring using dietary logs including a budget for both calories and grams of fat


Exercise is thought to help with weight loss maintenance by:

1) filling the energy gap created by initial weight loss

2) maintaining fat free mass (that is, muscle mass), which is the primary determinant of 24 hour energy expenditure; and

3) improving the ability to regulate appetite.

Also, regular exercise clearly mitigates the excess risk for diabetes and coronary heart disease attributable to obesity.


Starting off physical activity with obese patients

a. For most patients with obesity, physical activity should be initiated slowly in the form of low-level aerobic activity, such as walking.

b. Walking is safe for nearly all patients and meets the important criteria for beneficial exercise, such as continuous elevation of heart rate and use of large muscle groups. Importantly, walking is free, can be done at almost any time of day and in any location, does not require developing a new skill, and can be done as a social activity.

c. Depending on the patient’s progress, the amount of weight lost, and the patient’s overall physical condition, more strenuous physical activity can be initiated (programmed activity, such as running, elliptical, weight training).

d. It is also important to increase a patient’s awareness regarding the importance of expending energy through activities of daily living (lifestyle activity).


Doing more physical activity throughout the day can be helpful with weight management.

a. This includes taking the stairs whenever possible and seeking opportunities to walk.

b. Patients that can achieve the same calorie expenditure through lifestyle activity are equally successful with weight management, although achieving this goal is difficult for the typical patient.

c. The corollary to increasing activity throughout the day is reducing time spent in highly sedentary activities, such as watching television.

d. A randomized trial showed that simply having the TV turned off (involuntarily) led to an increase in 24 hour energy expenditure.

e. The ultimate goal is to make being physically activity a permanent part of lifestyle.


Two other factors have emerged in recent years that appear to impact weight.

a. Sleep is the first.
i. Adequate duration and quality of sleep have a very important role in preventing weight gain.
ii. This has been shown in multiple epidemiological studies and has been demonstrated in at least one randomized trial.
iii. The role of sleep makes it critical to screen obese patients for sleep apnea and ensure that OSA, if present, is treated. Patients with undiagnosed OSA will have a harder time losing weight.

b. A second factor is patients’ social environment.
i. Population-based studies and modeling studies suggest that social networks and other social factors, such as proximity to supermarkets and parks, are associated with lower weight.
ii. These studies are limited in their ability to show causation.
iii. However, a randomized trial showed that low income women who were randomly assigned to live in a higher income neighborhood had lower rates of severe obesity and diabetes than low income women who were allowed to live anywhere they wanted.


There appears to be a biological predisposition to weight regain

a. There is a reduction in 24 hour energy expenditure beyond that expected from the loss of weight and loss of lean body mass alone.

b. There is also an increase in subjective hunger, accompanied by an increase in ghrelin (a hormone that mediates hunger), a decrease in leptin (a hormone that mediates fullness), as well as changes that can be seen on functional MRI imaging indicating that weight reduced individuals have more activation in certain brain areas when shown pictures of highly palatable foods.

c. Together, these changes make it clear that a weight reduced individual is different from an individual who weighs the same but is not weight reduced.


. How Much Physical Activity Is Enough?

a. It is not practical to attempt to lose weight by increasing physical activity without also restricting food intake. Increased physical activity without caloric restriction causes a small amount (average of 1-3 kilograms) of weight loss, because the amount of additional negative energy balance induced is modest.

b. The amount of physical activity required to burn 500-1000 calories per day is several hours per day.

c. In contrast, many studies have found high levels of physical activity to be a strong predictor of success in maintaining a weight loss.

d. The strong association between weight loss maintenance and high levels of activity is seen regardless of the method used for the initial weight loss.


In reduced weight women followed over 12 months...

a. In reduced weight women followed over 12 months, the threshold level of physical activity required to prevent weight regain (>4.5 kg) was [47 kcal per (kg of body weight x 0.1)] – 1.
i. For a 70 kg person, this would equal to (47 x 70 x 0.1) – 1 = 328 kcal.

b. This threshold level corresponds to approximately 80 minutes per day of moderate-intensity (4 METs) physical activity (e.g. brisk walking) or 35 minutes per day of vigorous (6 METs) physical activity (e.g. fast cycling, aerobics, jogging).

c. Thus, it would appear that at least 30 minutes per day of vigorous activity or at least 60 minutes per day of moderate activity is required in most people to prevent weight regain.

d. This amount of exercise is significantly more than what the average American does and helps to explain why obesity rates have continued to increase over the past 40 years and why many individuals who lose weight have difficulty maintaining their weight losses.


Tools and Strategies for Developing an Activity/Exercise Plan

a. When developing an activity plan a number of factors should be taken into consideration.

b. These factors include a patient’s current body size, past history of activity, current fitness and activity level, barriers to activity, and readiness to make a change in his or her activity status.

c. Think of exercise as a medication and prescribe an exercise/activity plan that fits the patient. If the patient experiences “side effects” or can’t comply with one plan switch to another but be specific in the details of the plan just like you would be when prescribing a medication.

d. As with giving dietary advice, simply saying “move more” or “get more activity” is not helpful for most patients.
i. Rather, give the patient (or better yet, have the patient give you) a recommended type amount of exercise.


One method to use in designing an activity prescription is the F.I.T.T. (Frequency, Intensity, Time, Type) principle:

a. Frequency: Most or all days of the week

b. Intensity: Moderate intensity to start (approximately 60% of maximum predicted heart rate)

c. Time/Duration: 30 minutes per day, in blocks of at least 10 minute each

d. Type: activities that use large muscle groups and are continuous (for example, walking)


Increasing lifestyle physical activity using pedometers is another option.

a. Patients are instructed to wear a pedometer for one week without changing their routine activity to obtain a baseline number of steps/day.

b. After the baseline number of steps is determined, the patient can set a step goal that is 500 steps/day higher than the baseline number.
i. 500 steps is equivalent to about 5 minutes of brisk walking.

c. Patients can slowly increase their lifestyle step activities by increasing their step goal by 3500 steps each week (500 per day).

d. Ultimately, patients should aim for 10,000-12,000 steps/day to maintain a weight loss long-term.
i. This may be difficult for many patients as our home and work environments are not structured to facilitate large amounts of walking.

e. Thus, most individuals will need to add structured exercise (e.g. treadmill) to their daily walking regimen.


Predictors of Success in Weight Loss Maintenance

a. The National Weight Control Registry (NWCR) is a database of individuals across the United States who have lost at least 30 pounds and kept it off for at least 1 year.

b. Extensive surveys of this population have been conducted.

c. Individuals in this database used many methods to induce weight loss, but their methods of keeping off weight are similar.


Below are 5 strategies that NWCR participants have in common to help with weight loss maintenance.

1. Use of moderately low fat, high carbohydrate diets. NWCR subjects report eating a diet containing 24% fat, 19% protein and 55% carbohydrate. Even at the height of popularity for low carbohydrate diets, most of the people entering the NWCR reported eating a low fat diet to keep their weight off.

2. Frequent self-monitoring. A common characteristic among NWCR participants is that they weigh themselves frequently. Almost all of them weigh at least once per week, and many weigh themselves daily.

3. Eating breakfast. Of NWCR participants, 78% report eating breakfast 7 days/week, and 90% eat breakfast 4 or more days/week. Only 4% report never eating breakfast.

4. Large amounts of physical activity. NWCR participants report engaging in very high levels of physical activity to maintain their weight loss. From self-report, the average energy expenditure due to physical activity is about 2800 kcal/week. This corresponds to approximately one hour each day of moderate intensity physical activity. Walking was the most frequently reported form of physical activity. In a subsample of NWCR participants that wore pedometers, their average number of steps/day was about 11,000. This is in contrast to the average number of steps for a sedentary person who works at a desk job, which is approximately 5,000/day.

5. Limiting TV viewing. NWCR participants spend a relatively minimal amount of their time watching television. A relatively high proportion (63.5%) of participants report watching <10 hours/week at the time of entry in the NWCR. Over a third (38.5%) reported watching <5 hours whereas only 12.5% watched ≥ 21 hours per week. These numbers contrast markedly from the national average of 28 hours of TV viewing per week reported by American adults.


Obesity Treatment Introduction

The clinical approach to obesity can be viewed as a pyramid consisting of several levels of therapeutic options.

a. All patients should be involved in an effort to change their lifestyle behaviors to decrease energy intake and increase physical activity.

b. Lifestyle modification also should be a component of all other levels of therapy. Pharmacotherapy can be a useful adjunctive measure for properly selected patients.

c. Bariatric surgery is an option for patients with severe obesity who have not responded to less-intensive interventions. The number of obese patients who require a specific level of treatment decreases as one moves up the pyramid.


Obesity Treatment Pyramid

a. Lifestyle modification, which involves a program of appropriate diet, physical activity, and behavior therapy, should be considered for all patients with a body mass index (BMI) 25 kg/m2.

b. Long-term pharmacotherapy should be considered in appropriate patients who were unable to achieve adequate weight loss after 6 months of lifestyle therapy and who have a BMI 30 kg/m2, or 27 kg/m2 with concomitant obesity-related disease.

c. Bariatric surgery may be necessary in patients with severe obesity who failed to lose weight with nonsurgical therapy.
i. Eligible surgical candidates should have a BMI 40 kg/m2 or a BMI 35 kg/m2 and a concomitant serious obesity-related disease.


Currently Available Options

a. Accept weight where it is

b. Diet/Exercise: 3-10% weight loss

c. Drugs: 5-10% weight loss

d. Medically Supervised/Combination
of Diet + Drug: 10-15% weight loss

e. Surgery: 15-30% weight loss


Energy Metabolism in Lean and Obese Subjects

a. Most obese persons do not have an abnormal reduction in energy metabolism.

b. Both total energy expenditure and resting energy expenditure are usually greater in obese than lean persons who are of the same height and gender because of greater body cell mass (both fat and fat-free cell masses) in obese persons.

c. Therefore, obese persons must consume more calories than lean persons to maintain their larger body size.


Discrepancy Between Reported and Actual Energy Intake and Expenditure

Discrepancy between reported and actual energy intake and expenditure

a. A subset of obese patients believe that they are unable to lose weight despite careful adherence to a low-calorie diet (<1200 kcal/d).
i. These patients often assume that a metabolic defect in energy metabolism is responsible for their difficulty in losing weight.

b. This figure shows the results of a study involving 10 patients (1 man, 9 women) who had repeatedly failed to lose weight despite multiple attempts with low-calorie diet therapy
i. All patients were placed on a low-calorie diet for 14 days.
ii. Measures of total daily energy expenditure, by using the doubly-labeled water technique, and self-reported dietary intake were obtained throughout the study.

c. Body composition, measured by hydrodensitometry, was determined at the beginning and end of the study.
i. Actual food intake was calculated from measures of total energy expenditure and changes in body composition.

d. The data demonstrated that these subjects reported good compliance with their diet and activity program, but under-reported their actual energy intake by 47% and over-reported their actual physical activity by 51%.


Relationship Between Resting Energy Expenditure and Fat-free Mass

a. Resting energy expenditure (REE) correlates closely with fat-free mass in lean and obese men and women.

b. Although energy expenditure of metabolically active organs is responsible for a large component of REE, fat free-mass, which is composed primarily of skeletal muscle, accounts for most of the variability in energy expenditure between individuals.

c. This figure demonstrates that both fat-free mass and REE generally are greater in obese than lean persons, but REE follows the same regression line in lean and obese subjects across a wide range of fat-free masses.


EE Before and After Weight Loss*

a. To overcome weight loss plateau and continue to lose weight requires further energy restriction.

b. To stay in energy balance and maintain lower body weight you must eat less and/or or move more.

c. Most of the 350 kcal reduction difference in energy balance after weight loss is accounted for by an approximately 150-250 kcal reduction in resting metabolic rate. TEF, the thermic effect of food, remains relatively stable.
i. An additional 100-200 calorie reduction occurs in TDAT (total daily activity thermogenesis).


Weight Loss

a. Create a negative energy balance

b. Most practical way to achieve this is reducing food intake
i. honestly its lowering Kcal intake by diet

c. Goal is a reduction of 1 to 2 pounds per week

d. 500 to 1000 kcal/day caloric deficit


Physicians and Weight bias

a. Experimental Research:
Randomly assigned to view 1/6 patient vignettes that differed only by BMI and gender. Physicians rated heavier patients to be:
- less self-disciplined
- less compliant
- more annoying

b. As patient BMI increased, physicians reported:
- liking their jobs less
- having less patience
- less desire to help the patient
- seeing obese patients was a waste of their time.


Identify your personal attitudes

Ask yourself

How do I feel when I work with people of different body sizes?

Do I make assumptions regarding the character, intelligence, health status or behaviors of a person based only on weight?

Do my obese patients leave the office feeling empowered and more confident?


Get to know your audience

Recognize that patients may have had negative experiences w/health professionals.

Accept that most adults have tried to lose weight before.

The first step in treating overweight and obese patients is a thorough clinical assessment focused on social, psychological, medical, environmental and behavioral factors contributing to obesity.”