Flashcards in Obesity Treatment: Diet and Activity Deck (70)
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
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).
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
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.”
Mr. Ramirez, can we talk about your weight?
a. This is a somewhat controversial topic among physicians. This was a study in which female patients enrolled in a clinical trial were surveyed about what terms they would prefer their primary care physicians to use in addressing weight management with them.
b. The bottom line is that patients do not like the term obesity, even though it is a clinically correct term.
c. Obese patients tend to think of themselves as “overweight” and to associate the word obesity with the appearance of someone who is morbidly obese.
d. I use the results of this study in my clinical practice, so that my first question is: “can we talk about your weight for a minute?”
Tools and Strategies for Decreasing Dietary Intake
a. Food Diaries and Record Keeping
b. Fat Gram Budget
i. Based on calories and percent fat
c. Meal Replacements
i. Portion and fat control
d. Decrease portions by 25-33%
e. Reduce energy density
f. Diet Books/Commercial Programs
Self-Monitoring: Food Record
a. Self-monitoring is the systematic observation and recording of target behaviors and is the cornerstone of behavioral treatment.
b. Self-monitoring tools include records of food intake (including type, amounts, energy content, and times, place, and feelings associated with eating); physical activity logs to record frequency, duration, and intensity of exercise; and weight scales to measure changes in body weight.
c. Self-monitoring increases patients’ awareness of their behaviors, generates records that can be reviewed by healthcare professionals, and provides targets for interventions.
d. Self monitoring of dietary intake correlates with successful long-term weight control and reduces the tendency to underestimate food intake
e. Patients initially keep records of their food intake without attempting to change their diet.
i. This information can then be used to provide dietary advice to reduce caloric intake by 500 to 1000 kcal/d, to achieve a weight loss of approximately 1-2 pounds per week.
Keep Food Records, Lose Weight
a. Sibutramine is now off the market in the U.S., but the results of this post-hoc analysis are still important, in that they show record keeping was strongly associated with greater weight losses.
b.Within each treatment group, differences in weight loss between subjects in the lowest third of adherence as compared with those in the highest third of adherence were significant as determined by Wilcoxon rank-sum tests.
c. In the combined therapy group, the 19 subjects in the middle third of adherence completed 100.7±9.6 records and lost 12.2±9.8 kg, whereas in the group treated by lifestyle modification alone, the 19 subjects in the middle third of compliance completed 100.3±8.5 records and lost 8.7±7.2 kg.
Suggested Energy Intake Based on Initial Body Weight
a. In practice it is difficult to determine the amount of calories that should be prescribed to achieve a specific energy deficit because it is difficult to know a patient’s total energy requirements.
i. This table provides suggestions for dietary energy intake based on initial body weight
b. The estimated energy deficit increases with increasing body weight. The target energy deficit in very heavy patients is higher than those recommended by the NIH guidelines, but may be desirable for many patients in these weight categories.
c. Some patients may not fully comply with their prescribed diet or the estimate of desired energy intake may be inaccurate. Therefore, dietary energy content should be regularly adjusted based on a trial-and-error approach in order to achieve an appropriate rate of weight loss (approximately 1% weight loss per week).
Recommended Nutrient Content of a Weight-Reducing Diet
a. Dietary guidelines proposed by the National Institutes of Health recommend a 500 kcal/d deficit for overweight persons (BMI 25.0-29.9 kg/m2) who have obesity-related complications, and for persons with class I obesity (BMI 30-34.9 kg/m2).
i. This energy deficit will result in approximately a 1-lb (0.45 kg) weight loss per week and about a 10% weight reduction at 6 months.
b. A 500-1000 kcal/d deficit is recommended for those with class II (BMI 35.0-39.9 kg/m2) or class III (BMI 40 kg/m2) obesity, which will produce about a 1- to 2-lb weight loss per week and a 10% weight loss at 6 months.
c/. The recommended macronutrient composition for a low-calorie weight loss diet is shown in this figure and includes 55% or more of daily calories from carbohydrates, 15% from protein, and 30% or less from fat.
d. In addition, specific recommendations are made regarding the composition of fat ingestion: total energy intake should be comprised of 8%-10% calories from saturated fat, 10% or less calories from polyunsaturated fats, and 15% or less calories from monounsaturated fats.
i. Daily cholesterol intake should not exceed 300 mg/d, and daily fiber intake should be between 20-30 g/d.
Ad Libitum Low-Fat Diets Decrease Daily Energy Intake
a. Dietary fat is composed primarily of triglycerides, which increase food palatability and energy-density.
i. Therefore, low-fat diets often are prescribed for obese patients because these diets facilitate energy restriction.
b. This figure shows the individual and combined results from 12 controlled trials, involving a total of 1910 subjects, that evaluated the effect of an ad libitum low-fat diet on daily energy intake
c. At baseline, all subjects consumed a diet that contained approximately 38% of total calories as fat. For context, recommended fat intake in the USDA dietary guidelines is less than 30% of calories. Initiating an ad libitum low-fat diet resulted in a weighted overall 10.8% decrease in the percent of total calories consumed as fat and a 1138 kJ/d (272 kcal/d) decrease in energy intake, as compared with the control group (P=0.002).
Decreasing dietary fat is associated with a decrease in body weight
a. The data show that decreasing dietary fat was directly associated with a decrease in body weight.
b. Changes in percent dietary fat were also highly correlated with changes in energy intake.
c. For every 1% decrease in energy from fat there was a corresponding 0.28 kg weight loss. The broken line illustrates that a 10% decrease in the percent of calories from fat was associated with a 3-kg decrease in body weight.
Mediterranean or Low-Carbohydrate Diet Better at 2 Years than Low-Fat Diet
a. At the end of the study, individuals assigned to Mediterranean diet or low-carbohydrate diet lost more weight than those following a traditional low-fat diet.
b. Two caveats to this study is that:
1) it was done in Israel, where a Mediterranean diet is widely available; and
2) meals were prepared at a cafeteria in a workplace, so subjects did not have to choose their own foods.
c. * It would be difficult to replicate this study in the U.S. with free living participants.
Low Carb, Low Fat: No Difference in Weight Loss at 2 Years
a. Besides the randomized trial by Shai et al shown above, this study is the longest randomized trial to compare low fat and low-carbohydrate diets.
b. The results show that weight losses were similar at all time points, with participants losing over 11% of initial weight after the first 6 months and then regaining some weight out to Year 2.
c. Increases in HDL cholesterol, shown in the figure on the right, were better in the low carb group but all other parameters (e.g., blood pressure, triglycerides) were similar in the two groups.
Macronutrient Content of Diet Did Not Affect Weight Loss at 2 Years
*The take-home message here is that, on average, macronutrient composition is NOT as important as caloric restriction and self-monitoring.*
a. This study randomly assigned 811 individuals to diets with different macronutrient contents.
i. The targets for percentage of calories from protein was either 15% of 25%, for fat was either 20% or 40%, and for carbohydrate ranged from 35% to 65%.
b. All the study participants were offered individual and group counseling to help them meet the dietary recommendations.
i. After 6 months, participants lost approximately 6 kg, which was 7% of initial weight, but after 2 years, weight losses were similar in all the groups.
c. The top left hand corner of the figure above shows a trend towards greater weight loss among participants assigned to either high-protein or low-carbohydrate groups, but the difference was not clinically or statistically significant.
d. The take-home message here is that, on average, macronutrient composition is not as important as caloric restriction and self-monitoring.
Diet energy density, independent of fat content, influences energy intake
a. In this study, 18 lean women were given free access to either low, medium, or high energy density meals for 2 days on three separate occasions
b. The macronutrient content (percentage of calories from fat, protein, and carbohydrates) was the same for each diet and each diet had similar palatability ratings.
c. The study participants ate a similar weight of food during each 2-day test period, although the available foods varied in energy density.
d. Compared with the consumption of high-energy-dense foods, the consumption of low-energy-dense foods was associated with a 30% reduction in daily energy intake.
e. Despite this difference in energy intake, subjects felt just as full when eating the low-energy-dense diet as when eating the high-energy-dense diet.
Diet energy density influences short-term body weight
a. Data from short-term intervention studies suggest that altering energy density can have a beneficial effect on body weight in overweight and obese persons.
b. The results showed that diet energy density was directly associated with total energy intake, which affected body weight.
c. During the 14-day period of high-energy-density food consumption (39% fat, 48% carbohydrate, 13% protein; 737 kJ/100 g), subjects gained about 2 lb, whereas during the 14-day period of low-energy-density food consumption (38% fat, 49% carbohydrate, 13% protein; 373 kJ/100 g), subjects lost about 2 lb. Body weight did not change when medium-energy-density (40% fat, 47% carbohydrate, 13% protein; 549 kJ/100 g) foods were consumed.
d. Additional studies are needed to evaluate the long-term effect of low-energy-density diets on body weight.
Effect of portion size on energy intake
a. Food portion size affects energy intake. In this study, young adult men and women were served four different portions of macaroni and cheese for lunch on different days, and were allowed to consume as much food as they liked
b, The data demonstrate a linear relationship between portion size served and intake: increasing the amount of macaroni and cheese served increased the amount that was consumed.
Weight Change With Meal Replacements versus Energy Restricted Diet
a. This was a long-term study of the use of meal replacements.
i. Patients were initially randomized to calorie restricted diet, with or without meal replacements.
b. The difference in weight loss after the first 3 months was approximately 6 kg. Patients in both groups were then allowed to use meal replacements in an “open label” fashion for up to a total of 4 years, with 1 meal and 1 snack replaced on a long-term basis.
c. At the end of this time, participants in the two groups had lost 8.4% versus 3.2% of initial weight
Efficacy of Self-Help Diets
a. These are the results of a four-arm randomized trial of popular self-help eating plans. 160 overweight and obese participants were randomly assigned to 4 diet types.
b. Outcomes: mean weight loss, changes in CVD risk factors, and adherence at 1 year
c. Weight loss: associated with self-reported dietary adherence (r = 0.60; P
And the Best Diet is …
a. Among 59 eligible articles reporting 48 unique randomized trials (including 7286 individuals) and compared with no diet, the largest weight loss was associated with low-carbohydrate diets
b. Weight loss differences between individual diets were minimal.
i. For example, the Atkins diet resulted in a 1.71 kg greater weight loss than the Zone diet at 6-month follow-up.
ii. Between 6- and 12-month follow-up, the influence of behavioral support (3.23 kg [95%CI, 2.23 to 4.23 kg] at 6-month follow-up vs 1.08 kg [95%CI, −1.82 to 3.96 kg] at 12-month follow-up) and exercise (0.64 kg [95%CI, −0.35 to 1.66 kg] vs 2.13 kg [95%CI, 0.43 to 3.85 kg], respectively) on weight loss differed.
High Intensity Programs
a. Participate for ≥ 6 months … comprehensive lifestyle program that assists participants in adhering to a lower calorie diet and in increasing physical activity through the use of behavioral strategies.
b. On-site, high-intensity (i.e., ≥14 sessions in 6 months) …individual or group sessions … trained interventionist.
c. Electronically or telephonic programs that include personalized feedback … may result in smaller weight loss than face-to-face interventions.
d. Some commercial-based programs that provide a comprehensive lifestyle intervention can be prescribed …provided there is peer-reviewed published evidence of their safety and efficacy.
Maintenance after Weight Loss
a. Participate long-term (≥1 year) in a comprehensive weight loss maintenance program.
b. Prescribe face-to-face or telephone-delivered weight loss maintenance programs
c. Regular contact (monthly or more frequent) with a trained interventionist
Other Popular Weight Loss Programs
Take Off Pounds Sensibly (TOPS)
Tools and Strategies for Decreasing Dietary Intake
a. Have a diet approach
i. Just eat less is not an approach
b. Try different approaches
i. Use self-monitoring with all approaches
ii. Low energy density with all approaches
iii. Small portion sizes with all approaches
c. There is not clearly a single “best” diet in terms of macronutrient content
Reducing Television Time Results in Better Energy Balance
a. This elegant study tested the effect of reducing screen time. They recruited individuals that reported watching at least 3 hours per day of television. (Average TV watching during a 3 week observation period was 4.8 to 5.3 hours per day.)
b. They went from 5 hours per day to 2.5 hours per day.
i. The results in the table show that there was a 300 kcal per day difference in total energy balance after a 3 week intervention period.
c. Although this was not statistically significant, the study was quite small (36 households), but the effect is very likely to be clinically significant.
d. This study supports the concept that reducing screen time is an important part of preventing and treating obesity. Other research shows that resting metabolic rate is lower during TV watching than during any other sedentary activity. Thus, not all “screen time” is the same.
Low sleep and obesity...
Short sleep duration undermines dietary efforts at weight loss
Weight Loss Maintenance
a. Create energy balance at a reduced body weight
b. Physical activity is essential for weight loss maintenance success
Physical Activity Usually Does Not Increase Short-Term Diet-Induced Weight Loss
Data from randomized controlled studies suggest that adding exercise to dietary therapy does not significantly increase short-term weight loss compared with dietary therapy alone
This figure shows the results from 6 studies that compared short-term (4-6 months) diet therapy alone with diet therapy plus exercise
Only one study found a statistically significant, but small, improvement in weight loss with diet therapy plus exercise versus diet therapy alone
Physical Activity and Weight Loss
Most studies suggest a reasonable amount of physical activity
1. Does not produce weight loss
i. Exercise alone - 0.06 to 0.1 kg/week
ii. There is a dose response relationship, exercise alone would result in weight loss if the average patient could perform extreme amounts of activity
2. Does not significantly increase initial weight loss over what is obtained by caloric restriction alone
i. May produce slight improvements in body composition as a result of weight loss (higher percent fat loss then lean tissue loss)
Calories Expended During Exercise
a. Difficult to create energy deficit required for weight loss with activity alone.
b. Difficult to maintain caloric restriction for long periods of time, thus exercise appears to be critical for long term weight loss maintenance.
c. Most individuals who succeed at long term weight loss maintenance exercise regularly.
d. Long-term benefit of exercise in weight management probably has mechanisms other than simply the number of calories burned
Benefits of Regular Physical Activity in Obese Persons
a. Decreases loss of fat-free mass associated with weight loss
b. Improves appetite regulation
c. Improves cardiovascular and metabolic health, independent of weight loss
Physical Activity Helps Preserve Fat-Free Mass During Weight Loss
Physical activity helps preserve fat-free mass during weight loss
a. Approximately 75% of weight that is lost by dieting is composed of fat and 25% is fat-free mass (FFM)
b. Adding a physical activity program to dietary therapy can affect the composition of weight loss.
c. In subjects with a mean weight loss of 10 kg, regular exercise decreased the percentage of weight lost as FFM by half, from approximately 28% to 13% in men and from 24% to 11% in women (P<0.05).
d. However, this large difference in percentage of weight lost as FFM represented only a small (approximately 1 kg) difference in the absolute amount of FFM lost between groups.
i. Moreover, conservation of FFM does not necessarily represent conservation of muscle protein; the greater retention of FFM associated with exercise may be related to increased retention of body water and muscle glycogen.
ii. It is not known whether performing resistance exercise while dieting leads to greater conservation of FFM than performing endurance exercise because of limited and conflicting data
Effect of Low-Activity (1000 kcal/wk) and High-Activity (2500 kcal/wk) on Body Weight
a. Effect of low-activity (1000 kcal/wk) and high-activity (2500 kcal/wk) on body weight
b. Retrospective analyses of data from weight loss trials have found that a large amount of physical activity (>60 min/day of walking) is associated with maintenance of weight loss in obese subjects who lost weight by dieting.
i. The data shown in this figure are from a randomized controlled trial that evaluated the effect of a low-calorie diet and standard behavior therapy plus either a low (1000 kcal/wk=walking 30 min/day) or a high (2500 kcal/wk=walking 75 min/day) physical activity prescription on body weight
c. In contrast to data from retrospective analyses, high physical activity did not prevent weight regain.
d. However, weight regain was less in subjects randomized to high than to low physical activity. The high physical activity group also reported more exercise-related injuries than the low physical activity group.
How Much exercise is Enough?
Current PA Recommendations
Minimal public health recommendations to improve health related outcomes
a. 30 min moderate activity most days of the week (150 minutes/week)
-CDC - Centers for Disease Control
-ACSM - American College of Sports Medicine
-SG - Surgeon General
b. Prevent weight regain
i. 60 minutes/day
IOM - Institute of Medicine
ii. 60-90 minutes/day
-IASO - International Assoc for Study of Obesity
iii. 60 minutes/day (300 minutes/week)
-ACSM - American College Sports Medicine
2008 Physical Activity Guidelines for AmericansUS Department of Health and Human Services
-2 hr 30 minutes a week of moderate intensity, or 75 minutes per week of vigorous intensity aerobic PA
-Additional health benefits are provided by increasing to 5 hours a week of moderate intensity activity or 2 hours 30 minutes a week of vigorous intensity activity
-Muscle strengthening activities should be performed on 2 or more days per week
-1 hour or more of activity every day
-Most of the hour should be either moderate or vigorous intensity aerobic PA
-Vigorous intensity activity should be performed on at least 3 days per week
-Muscles/bone strengthening activities should be done at least 3 days per week
Recommendations for Increasing Physical Activity In Clinical Practice
a. If ready-give specific advice
b. As with diet, “move more” is not usually enough
c. Set goals
d. Physical activity prescription
e. FITT- Frequency, Intensity, Time and Type
How to Get Your Overweight Patients to Be More Active
a. Structured exercise regimens not always possible
b. Use small changes to increase daily physical activity
-Park at end of lot when driving to store
-Only have one phone in house so patient has to walk to use it
-Find the stairs!
-Walk to a co-worker’s office instead of calling on the phone
-Use elevators only if going up more than 2 floors
c. Decrease sedentary activity
i. Limit recreational screen time
ii. Increase active household activities (gardening, pets, children)
Weight Maintenance Can Be Achieved with Either Programmed or Lifestyle Activity
*These findings demonstrate that education to alter lifestyle activities is a reasonable alternative to programmed exercise for obese patients.*
a. Increasing daily lifestyle activities can be just as effective as a structured aerobic exercise program in maintaining long-term weight loss.
b. In this study, obese women were randomized to 16 weeks of treatment with a behavioral therapy program and a 1200 kcal/d diet with either structured aerobic exercise (three 45-minute step aerobics classes weekly) or instructions for increasing moderate-intensity lifestyle activities by 30 minutes per day on most days of the week (e.g. walk instead of drive short distances; take stairs instead of elevators)
i. After the 16-week treatment phase was completed, subjects attended 4 follow-up meetings (every 13 weeks) for 1 year.
c. The figure shows that initial weight loss was similar in both groups at 16 weeks (8.3 kg in the programmed group vs 7.9 kg in the lifestyle group, P=0.08) and a trend toward better maintenance of weight loss at 68 weeks in the lifestyle activity participants than in the group that received programmed exercise (P=0.06).
d. These findings demonstrate that education to alter lifestyle activities is a reasonable alternative to programmed exercise for obese patients.
Lifestyle Pedometer Activity Program
a. Wear a pedometer every day for a week to determine baseline
b. Increase steps by 500 steps/day /week
c. Ultimate goal 10,000 - 15,000 steps/day
d. 500 steps = 5 minutes walking moderate
e. Helps set goals and gives instantaneous feedback
f. Alternative: minutes/day of activity
NWCR: Weight Loss and Maintenance Strategies
Founded in 1994 by Drs. James Hill and Rena Wing
Registry of “successful losers”
Minimum of 30 lbs of weight loss for a minimum of one year
Average weight loss 33kg (~ 73 lbs)
Average maintenance of at least a 13.6 kg weight loss is 5.7 yrs
Max BMI 36.7 to Reduced BMI 25.1
Behaviors of Successful Long-Term Weight Management
National Weight Control Registry Data
*Review this slide
i. Diet: record food intake daily, limit certain foods or food quantity
ii. Weight: check body weight 1x/wk
b. Low-calorie, low-fat diet
i. Total energy intake: 1300-1400 kcal/d
ii. Energy intake from fat : 20%-25%
c. Eat breakfast daily
Regular physical activity = 2800 kcal/wk
Limit TV Viewing = less than 2 hours/day
WHY CAN WE LOSE WEIGHT
BUT NOT KEEP IT OFF?
Ghrelin is a hunger hormone, the others are fullness/satiety hormones. This study raises all kinds of questions, such as: how long does it take for these hormonal profiles to normalize? Do they ever normalize? Does it depend on how overweight the person is, or how long they’ve been overweight? Is there a threshold effect above a certain weight?