Obesity and Weight ManagementManual of Clinical Nutrition Management III- 85 Copyright © 2013 Compass Group, Inc.
whole grain breads, cereals, and legumes, are recommended. The daily consumption of 20 to 35 g of fiber
reduces the energy density of foods consumed and promotes satiety by delaying gastric emptying (17). The US
Department of Agriculture has found that diets high in carbohydrate (>55%) and low to moderate in fat (15%
to 30%) tend to be lower in total energy and higher in diet quality when compared to low-carbohydrate diets
(<30%) (19). High-carbohydrates diets have been scrutinized based on outcomes and personal testimony of
individuals who follow popular low-carbohydrate diets. A randomized controlled trial published in 2003
investigated weight loss outcomes using a low-carbohydrate diet compared to a low-fat, low-energy high
carbohydrate (conventional) diet. Although the initial weight loss outcome was significantly greater in the
low-carbohydrate group, the difference between the two groups was not statistically significant at 1 year (24).
The difference in weight loss between the two groups in the first 6 months was attributed to an overall
greater energy deficit in the low-carbohydrate group (24). The low-carbohydrate diet was associated with
greater improvement in some risk factors for coronary heart disease. Adherence was poor and attrition was
high in both groups (24). Results of this study should be interpreted with caution, given the study’s relatively
small sample size and the 1-year duration (24). Longer and larger studies are required to determine the long-
term safety and efficacy of low-carbohydrate diets that are high in protein and fat (24). The low glycemic index
diet is not recommended for weight loss or weight maintenance, since studies have not shown it to be
effective in these areas (Grade I) (7).
Calcium: A review of evidence suggest calcium intake lower than the recommended level is associated with
increased body weight (Grade II) (6,7). However, the effect of calcium at or above recommended levels on weight
management is not clear (Grade II) (6,7). Incorporating 3 to 4 servings of low-fat dairy foods a day as part of the
diet component of a comprehensive weight management program is suggested (6).
Physical activity: The US Surgeon General’s Report on Physical Activity and Health recommends 30 minutes
of moderate to vigorous physical activity per day for children and adults (18). Physical activity contributes to
weight loss, may decrease abdominal fat, and may help with maintenance of weight loss (Grade I) (7). Increased
physical activity should be a key component of a weight-loss program (4,6,7). A combination of weight
resistance or strength training and aerobic exercise is recommended to preserve lean body mass and
promote the loss of adipose tissue (4). Federal Physical Activity Guidelines for Americans make
recommendations in weekly versus daily doses (6,25). These guidelines suggest that many people may need
more than the equivalent of 150 minutes/week of moderate-intensity physical activity to maintain their
weight and more than 300 minutes/week (or 42 minutes/day) to meet weight-control goals (25). Long-term
goals should be to accumulate at least 30 minutes of moderate intensity physical activity on most, preferably
all, days (unless medically contraindicated) (Grade I) (7).
Behavior modification: Behavior modification is an integral component of weight loss and weight
management and, in addition to diet and physical activity, leads to additional weight loss (Grade I) (4,6,7).
Behavior modification is based on the premise that eating is a conditioned response. A goal of behavior
modification is to help the patient realize and eliminate the associations that control eating behavior. Portion
control, one method of behavior modification, at meals and snacks results in reduced energy intake and
weight loss (Grade II) (6,7). A comprehensive weight management program should make maximum use of
multiple strategies for behavior therapy (eg, self-monitoring, portion control, stress management, stimulus
control, problem solving, contingency management, cognitive restructuring, and social support) (7).
Continued behavior interventions may be necessary to prevent a return to baseline weight (Grade I) (7).
Very-low-calorie diets (VLCD): These specialized feeding regimens provide 800 kcal/day (or 6 to 10
kcal/kg) or less per day, is enriched with high biological value protein and provides at least 100% of the Daily
Value of essential vitamins and minerals (6). These diets consist of a premixed liquid or meat, fish, or poultry
(6). This type of diet is recommended only to patients who are at a very high health risk related to obesity.
Criteria for these regimens generally are a BMI of at least 30 kg/m^2 and previous failures from other
treatment approaches (6). Individuals on a VLCD should be supervised by a physician and receive
supplemental vitamins and minerals (26). The typical treatment duration is 4 to 6 months. Because patients
who consume less than 800 kcal/day are at risk for protein, vitamin, and mineral deficiencies, they should be
metabolically monitored. High-quality protein (0.8 to 1.5 g/kg of ideal body weight) and a minimum of 100 g of
carbohydrate should be provided each day (23). People with a history of gallbladder disease, cardiac abnormality,
cancer, renal or liver disease, type 1 diabetes, or HIV should use these regimens with caution. VLCDs produce
weight losses of 15% to 25% in 8 to 16 weeks (27). Adherence to VLCD’s results in lower calorie intakes and
therefore significant intial weight loss than reduced-calorie diets (Grade I) (6,7). Despite the short-term success of
achieving significant weight losses, there is poor long-term maintenance of the weight loss (Grade I) (6,7,26). Several