CALORIE-CONTROLLED DIET FOR WEIGHT MANAGEMENT

Description
For the Calorie-Controlled Diet for Weight Management, the Regular Diet is modified by reducing energy intake below what is necessary for maintenance of body weight.  Intake of essential protein, vitamins, and minerals is maintained by limiting the amount of fat and sugar in the diet and substituting low-energy foods for foods of similar nutrient content that are higher in energy.  Weight loss and weight maintenance therapy should be based on a comprehensive weight management program including diet, physical activity, and behavior therapy.  The combination therapy is more successful than any one intervention alone (Grade I)* (1).

*The American Dietetic Association has assigned grades, ranging from Grade I (good/strong) to Grade V (insufficient evidence), to evidence and conclusion statements. The grading system is described in Clinical Nutrition Management A Reference Guide.

Indications
Weight reduction is desirable because obesity is related to increased mortality and because weight loss reduces the risk factors for several chronic diseases.  Thus, weight loss may help to both control diseases worsened by obesity and decrease the likelihood of developing these diseases.  Strong and consistent clinical evidence supports weight loss in overweight or obese persons who have hypertension, hyperlipidemia, or type 2 diabetes, as well as in overweight or obese persons who are at risk for developing these conditions (Grade I) (1-6). Obesity is a significant risk factor for non-alcoholic fatty liver disease, an emerging condition that is the most common cause of abnormal liver function tests in obese children and adults (7).  Non-alcoholic fatty liver disease can lead to significant liver damage including cryptogenic cirrhosis, steatohepatitis, and hepatocellular carcinoma (7).  In overweight and obese persons, weight loss is recommended to (1-7):

• lower blood pressure in patients with hypertension (5)
• lower total cholesterol, low-density lipoprotein cholesterol, and triglycerides levels in patients with hyperlipidemia (4)
• lower blood glucose levels in patients with type 2 diabetes (3,4,6)
• prevent liver disease (7)
  

    Fat is lost when the body is in a state of negative energy balance, which is achieved by reduced energy intake, increased energy output (through muscle work), or both.  The reduction of total energy intake vs the macronutrient composition of the diet is the most important component for achieving negative energy balance and subsequent weight loss (8).

    Body mass index (BMI), defined as weight (kg) divided by height2 (m2), and waist circumference should be used to classify overweight and obesity, estimate risk for disease, and identify treatment options (Grade II) (1-3).  The BMI is highly correlated to obesity, fat mass, and risk of other diseases  (Grade II) (1-3).  For optimal health, a BMI of 18.5 to 24.9 kg/m2 is recommended for adults, based on evidence that this range is associated with minimal risk of disease.  Table C-3 outlines the health risk classes associated with different BMI levels and waist circumferences in adults aged 18 years and older. 

Children and adolescents:  Complications of obesity in children and adolescents include hypertension, dyslipidemia, orthopedic disorders, sleep disorders, gall bladder disease, and insulin resistance (9).  The National Heart, Lung, and Blood Institute Obesity Education Initiative Expert Panel recommends evaluations and possible treatment for: (1) children and adolescents who have a BMI greater than or equal to the 85th percentile and complications of obesity; and (2) children and adolescents who have or a BMI greater than the 95th percentile with or without complications of obesity (9).  The use of weight maintenance vs weight loss to achieve weight goals depends on the patient’s age, baseline BMI percentile, and the presence of medical complications (9). The committee recommends treatment that begins early, involves family, and institutes permanent changes in a stepwise manner (9).  (Refer to Obesity and Weight Management.)   

Contraindications

• Weight reduction is not recommended for the following groups:
• pregnant women (Energy restriction during pregnancy that is sufficient to produce weight loss can be dangerous for the development of the fetus.) (10)
• patients with unstable mental or medical conditions, unless medically supervised (2)
• patients with anorexia nervosa or a history of this disorder, unless medically supervised (2)
• terminally ill patients (2)

Nutritional Adequacy
The precise level at which energy intake is insufficient for an adequate diet is difficult to define without taking into consideration the age and sex of the individual and the corresponding Dietary Reference Intakes. Diets that provide 1,200 kcal or less of energy are generally inadequate to meet Dietary Reference Intakes.  Therefore, a daily multivitamin is recommended when energy levels of this range are prescribed (2,3).  Determining the energy level that promotes weight loss is difficult in overweight and obese individuals, and estimated energy needs should be based on resting metabolic rate (RMR) (Grade I) (1).  Whenever possible, RMR should be measured (eg, indirect calorimetry).  If RMR cannot be measured, the Mifflin-St. Jeor equation using actual weight is the most accurate method for estimating RMR for overweight and obese individuals (Grade I) (1).  (Refer to Estimating Energy  Expenditures.)  Meta-analysis of the literature has identified that 1,200 kcal/day for women and 1,400 to 1,500 kcal/day for men (2,3,8,11) are acceptable energy intake levels that promote gradual and safe weight loss of 0.5 to 1 lb/week (2,3,8).  An individualized reduced energy diet along with energy expended through physical activity should reduce body weight at an optimal rate of 1 to 2 lbs/week for the first 6 months and achieve an initial weight loss goal of up to 10% from baseline.  These goals are realistic, achievable, and sustainable (Grade I) (1).

    Recent studies have evaluated the impact of total energy and macronutrient composition on weight loss.  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%).  In these studies, the BMI was significantly lower for men and women on the high-carbohydrate diet; the highest BMIs were noted for individuals on a low-carbohydrate diet.  Based on these findings, weight loss is independent of macronutrient composition, and energy restriction is the key variable associated with short-term weight reduction (8,11).  A randomized controlled trial investigated weight loss outcomes using a low-carbohydrate diet compared to a low-fat, low-energy, high-carbohydrate (conventional) diet.  Initial weight loss was significantly greater in the low-carbohydrate group; however, after 1 year the difference between the groups was not statistically significant (Grade II) (1,12).  The difference in weight loss between the two groups in the first 6 months was attributed to overall greater energy deficit in the low-carbohydrate group (Grade II) (1,12).  The low-carbohydrate diet was associated with a greater improvement in some risk factors for coronary heart disease.  Adherence was poor and attrition was high in both groups (12).   Results of this study should be interpreted with caution, given the relatively small sample size and short duration (12).  Longer and larger studies are required to determine the long-term safety and efficacy of low-carbohydrate, high-protein, high-fat diets (12). A low-glycemic index diet is not recommended for weight loss or weight maintenance because it has not been shown to be effective in these areas (Grade I) (1).            

How to Order the Diet
The physician may specify any of the following:

• “Weight Reduction Diet”: The dietitian determines an appropriate weight loss goal and energy level.
• “____ kcal Diet”:  The dietitian plans an individualized meal plan within the energy prescription.
• Restriction of sodium, fat, cholesterol, or another dietary component: If a restriction is required, it should be prescribed along with the diet order.

    Initiation of a weight reduction diet is not usually recommended in a hospital setting.  Weight loss and weight maintenance therapy should be based on a comprehensive weight management program including diet, physical activity, and behavior therapy (Grade I) (1).  Medical nutrition therapy for weight loss should last at least 6 months or until weight loss goals are achieved, with implementation of a weight maintenance program after that time (Grade I) (1).  A greater frequency of contacts between the patient and practitioner may lead to more successful weight loss and weight loss maintenance (Grade I) (1).

    Moderate energy restriction for weight loss is recommended (2,3).  Individualized meal plans of 1,200 to 1,500 kcal/day for women and 1,400 to 2,000 kcal/day for men can promote retention of lean body mass while facilitating weight reduction when combined with physical activity and behavioral modification (2,3).  Reducing dietary fat and/or carbohydrate is a practical way to create an energy deficit of 500 to 1,000 kcal below estimated energy needs and should result in a weight loss goal of 1 to 2 lbs/week (Grade I) (1).  Portion control should be included as part of a comprehensive weight management program.  Portion control at meals and snacks results in reduced energy intake and weight loss (Grade II) (1).  In addition, total energy intake distributed throughout the day, achieved by the consumption of four or five meals/snacks per day (including breakfast), may be preferable and result in greater weight loss than eating in the evening (Grade II) (1).  For people who have difficulty with self selection or portion control, meal replacements (eg, liquid meals, meal bars, energy-controlled packaged meals) may be used as part of a comprehensive weight management program (Grade I) (1).  Substituting one or two daily meals or snacks with meal replacements is a successful weight loss and weight maintenance strategy (Grade I) (1).  When setting goals with patients, the dietitian should establish a realistic and practical target, such as a 5% to 10% decrease in the baseline weight or a decrease of 2 BMI units (Grade I) (1-3). 

    Successful weight reduction requires a commitment to behavioral change, family support, and attention to physical activity patterns (Grade I) (1-3).  Behavioral therapy should use multiple strategies including self-monitoring, stress management, stimulus control, problem solving, contingency management, cognitive restructuring, and social support (Grade I) (1).  Moderate physical activity promotes the maintenance of lean body mass, contributes to the energy deficit needed for weight loss, and may help with the maintenance of weight loss (Grade I) (1).  Physical activity should be assessed with individualized long-term goals established to accumulate at least 30 minutes of moderate-intensity physical activity on most, and preferably all, days of the week, unless medically contraindicated (Grade I) (1). 

    Weight loss medications approved by the Food and Drug Administration may be part of a comprehensive weight management program (1).  Clinicians should collaborate with other members of the health care team regarding the use of these weight loss medications for people who meet the criteria.  A BMI of 30 kg/m2 or greater with no comorbid conditions or a BMI exceeding 27 kg/m2 with comorbid conditions should be one criterion for the use of medications to treat obesity (3).  Other criteria include: failure to manage weight with more conservative behavioral methods; number and severity of associated comorbidities; absence of contraindications, such as depression or ischemic heart disease; and the need for short-term weight loss to reduce operative risk (2).  Depending on the type of medication, a loss of 10% to 15% of the baseline weight has been observed with the adjunct of lifestyle modification (low-energy diet and increased physical activity) (Grade I) (1,13).  Weight regain occurs after drug withdrawal; thus, long-term use is required to maintain the weight loss (13).  Data on the use of weight loss medication for longer than 2 years are limited, and the efficacy and safety of long-term treatment with pharmacologic agents remains unclear (1,13).  Pharmacologic agents are a useful adjunct to, but not a substitute for, necessary changes in diet and physical activity.  The effectiveness of pharmacologic intervention depends on its use with appropriate dietary nutrition intervention, increased physical activity, and lifestyle change (1,2). Refer to Bariatric Surgery for Obesity and Obesity and Weight Management for more information.

Planning the Diet

The dietitian should plan an energy-controlled diet to meet the individual needs and lifestyle of the client.  Suggestions to reduce daily energy intake include (1-5,13):

• Reduce intake of foods with high-energy density (eg, alcohol and fat).  Follow the US Dietary Guidelines of less than 30% energy from fat, 10% to 20% from protein, and 50% to 60% from carbohydrates.
• Reduce the total amount of food consumed by decreasing portion size and frequency of consumption.  Employ behavior modification techniques to improve control over the food selection process and the act of eating.
• Establish self-management training techniques that will enhance the satiety of meals but reduce the energy intake.  For example, encourage the patient to eat slowly so that the brain can register that the stomach is full, or recommend eating ample amounts of low-energy density vegetables (eg, salads with small amounts of salad dressing or fat-free dressing) to provide chewing satisfaction and fill the stomach.

References

1. Adult Weight Management Evidence-Based Nutrition Practice Guideline.  American Dietetic Association Evidence Analysis Library. American Dietetic Association; 2006.  Available at: http://www.adaevidencelibrary.com. Accessed August 1, 2006.
2. Position of the American Dietetic Association: weight management. J Am Diet Assoc. 2002;102:1145-1155.
3. National Heart, Lung, and Blood Institute Obesity Education Initiative Expert Panel. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report.  Bethesda, Md: National Institutes of Health; 1998.  NIH publication No. 98-4083.  Available at:  http://www.nhlbi.nih.gov/nhlbi/htm.
4. Executive Summary of the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III).  JAMA.  2001;285:2486-2497.  Available at: http:// nhlbi.nih.gov/guidelines/cholesterol/index.htm.
5. Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr, Jones DW, Materson BJ, Oparil S, Wright JT Jr, Roccella EJ, and the National High Blood Pressure Education Program Coordinating Committee.  Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.  Hypertension.  2003; 42:1206-1252.
6. Adult Diabetes 1 and 2 Evidence Analysis Project. American Dietetic Association Evidence Analysis Library. American Dietetic Association; 2006. Available at: http://www.adaevidencelibrary.com. Accessed August 15, 2006.
7. Festi D, Colecchia A, Sacco T, Bondi M, Roda E, Marchesini G.  Hepatic steatosis in obese patients: clinical aspects and prognostic significance.  Obes Rev.  2004;5:27-42.
8. Kennedy ET, Bowman SA, Spence JT, Freedman M, King J.  Popular diets: correlation to health, nutrition, and obesity.  J Am Diet Assoc.  2001;101:411-420.
9. Barlow SE, Dietz WH.  Obesity evaluation and treatment:  Expert Committee recommendations.  Pediatrics.  1998;102:1-11.
10. Subcommittee on Nutrition Status and Weight Gain During Pregnancy, Committee of Nutritional Status During Pregnancy and Lactation, Food and Nutrition Board, Institute of Medicine.  Nutrition During Pregnancy.  Washington, DC:  National Academy Press; 1990.
11. Kennedy ET, Bowman SA.  Assessment of the effect of fat-modified foods on diet quality in adults, 19 to 50 years, using data from the Continuing Survey of Food Intake of Individuals.  J Am Diet Assoc. 2001;101:455-460.
12. Foster GD, Wyatt HR, Hill JO, McGuckin BG, Brill C, Mohammed BS, Szapary PO, Rader DJ, Edman JS, Klein S.  A randomized trial of a low-carbohydrate diet for obesity.  N Engl J Med.  2003;348:2082-2090.
13. Fabricatore AN, Wadden TA.  Treatment of obesity: an overview.  Clin Diabetes.  2003;21:67-72.

Manual of Clinical Nutrition Management                                                     
Copyright © 2008 Morrison Management Specialists, Inc.
All rights reserved.