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EFFECTS OF A LOW-CARBOHYDRATE DIET ON WEIGHT LOSS AND CARDIOVASCULAR RISK FACTORS IN OVERWEIGHT ADOLESCENTS STEPHEN B. SONDIKE,MD,NANCY COPPERMAN,MS,RD, AND MARC S. JACOBSON,MD Objectives To compare the effects of a low-carbohydrate (LC) diet with those of a low-fat (LF) diet on weight loss and serum lipids in overweight adolescents. Design A randomized, controlled 12-week trial. Setting Atherosclerosis prevention referral center. Methods Random, nonblinded assignment of participants referred for weight management. The study group (LC) (n = 16) was instructed to consume <20 g of carbohydrate per day for 2 weeks, then <40 g/day for 10 weeks, and to eat LC foods according to hunger. The control group (LF) (n = 14) was instructed to consume <30% of energy from fat. Diet composition and weight were monitored and recorded every 2 weeks. Serum lipid profiles were obtained at the start of the study and after 12 weeks. Results The LC group lost more weight (mean, 9.9 ± 9.3 kg vs 4.1 ± 4.9 kg, P < .05) and had improvement in non-HDL cholesterol levels (P < .05). There was improvement in LDL cholesterol levels (P < .05) in the LF group but not in the LC group. There were no adverse effects on the lipid profiles of participants in either group. Conclusions The LC diet appears to be an effective method for short-term weight loss in overweight adolescents and does not harm the lipid profile. (J Pediatr 2003;142:253-8) 2 he prevalence of overweight and obesity, defined as body mass index (BMI, kg/m ) See editorial, p 225. >95th percentile, has more than doubled among children and adolescents in the Tpast three decades.1,2 Data suggest that BMI distribution from natural probability samples between 1970 and 1994 showed little or no difference at the lower percentiles but increasing differences at higher percentiles.3-5 Thus the heaviest children and adolescents are becoming markedly heavier. Long-term follow-up of obese pediatric patients into adulthood has shown that those who were most overweight as children were most likely to become obese as adults.6-9 Sequelae of obesity in the adolescent population include immediate biochemical ab- normalities or disease including dyslipidemia, insulin resistance, impaired glucose toler- 10,11 ance, and type 2 diabetes mellitus. Increased body fat mass in adolescents also is From the Division of Adolescent Medi- associated with major psychosocial difficulties, including isolation, depression, low self-es- cine, Schneider Children’s Hospital, New teem, and development of eating disorders.12 Hyde Park, New York. Preliminary data for this manuscript Considering the increasing prevalence of childhood and adolescent obesity, evalua- were presented at the Society for Ado- tions of new approaches to manage this problem are warranted. For example, very-low–car- lescent Medicine Annual Meeting, March 27, 2000. bohydrate (ketogenic), low-carbohydrate (LC) and low-fat (LF) diets have been shown to Submitted for publication Sept 27, 2001; be effective and well tolerated in promoting short-term weight loss in both children and revisions received Feb 14, 2002, July 1, adults.13-15 Potential advantages of the LC diet include increased protein sparing, greater 2002, and Sept 5, 2002; accepted Sept 23, 2002. Reprint requests: Stephen B. Sondike, MD, Division of Adolescent Health, BMI Body mass index Mount Sinai Medical Center, New York, LC Low-calorie NY 10128. LF Low-fat Copyright © 2003, Mosby, Inc. All rights PSMF Protein-sparing modified fast reserved. TC Total cholesterol 0022-3476/2003/$30.00 + 0 TG Triglycerides 10.1067/mpd.2003.4 253 Ta b le I. Baseline measurements stratified by group tients were excluded from participation if they exhibited any of the following: any chronic disease affecting growth, dia- Variable LC LF betes mellitus, familial hypercholesterolemia, clinically diag- (n = 16) (n = 14) nosed psychological disorders, any chronic medication use, abnormal thyroid, kidney, or liver function tests, or abnormal- Age (y) 14.4 ± 1.9 15.0 ± 1.8 ities in the complete blood count. Enrollment occurred over a Height (in) 63.4 ± 2.4 65.3 ± 5.2 period of 1 year. Nine patients were approached but declined (cm) 161.0 ± 6.1 165.9 ± 13.2 to consent. The reasons for refusal were concerns that the LC Weight (lb) 202.6 ± 32.7 219.0 ± 60.0 diet was unhealthy (3 of 9) and concerns that they would be (kg) 92.1 ± 14.9 99.5 ± 27.3 unable to maintain a LC diet (6 of 9). BMI (kg/m2) 35.4 ± 5.0 35.6 ± 5.8 After informed consent was obtained, 39 patients were Lipid values enrolled and randomly assigned into 2 diet treatment groups, TC (mg/dL) 196.9 ± 37.5 183.0 ± 40.1 the LC diet group (n = 20) and the LF diet group (n = 19). LDL-C (mg/dL) 133.3 ± 43.9 117.5 ± 29.2 THE INTERVENTION HDL-C (mg/dL) 43.8 ± 9.8 42.8 ± 8.9 TG (mg/dL) 119.3 ± 43.8 109.9 ± 37.8 The adolescents in the LC group were prescribed a diet Non–HDL-C (mg/dL) 148.4 ± 38.9 143.1 ± 37.6 that consisted of a daily intake of no more than 20 g/day of carbohydrate and an ad lib intake of protein, fat, and energy P = not significant for all LC versus LF. for the initial 2 weeks. For weeks 3 through 12, carbohydrate was increased to 40 g daily by adding additional nuts, fruits, lipolysis, and increased palatability. There is evidence that cir- and whole grains. Participants were advised to consume a culating ketones promote nitrogen sparing, thus maintaining minimum fluid intake of 50 oz per day, a multivitamin supple- lean body mass.16 ment containing 100% of the recommended dietary al- One ketogenic diet that has gained popular appeal is the lowances for age, and a potassium chloride table salt “Atkins Diet.”17 The recommended diet does not restrict fats substitute. Fiber supplements were prescribed when symp- or energy. Westman et al18 successfully evaluated such a diet toms of constipation occurred. in adults. Sharman et al19 demonstrated no harm to the lipid The LF group was instructed to eat a diet consisting of profile in adults on a ketogenic diet. Volek et al20 demonstrat- <40 g/d of fat, with 5 servings of starch per day and an ad libi- ed decrease in adiposity with maintenance of lean body mass tum intake of fat-free dairy foods, fruits, and vegetables for 12 on a meal plan that was 8% carbohydrate. To our knowledge, weeks. A serving of starch was defined as a portion containing no controlled studies of such a diet with regard to weight loss, 15 g of carbohydrate per serving, and the consumption of effects on serum lipids, or side effects have been reported in whole grains was encouraged. Juices and sweetened beverages the pediatric literature.21-25 were omitted from the meal plan. A multivitamin supplement The purpose of this study was to compare the effects of containing 100% of the recommended dietary allowances of a LC diet with self-selected energy intake to a LF diet with vitamins and minerals for age and sex was recommended. self-selected energy intake on weight loss in overweight ado- Both diets shared a “stoplight” meal plan design with 3 cate- lescents and to examine the effects of these diets on serum gories of foods, as suggested by Epstein and Squires.26 The lipids. We hypothesized that an energy-unrestricted, very-LC contents of the food categories were designed by the investi- diet without restriction of fats would result in more weight gators to correspond to the desired macronutrient content of loss compared with a LF diet over a 12-week period. We fur- each respective meal plan. Both groups were instructed to ther hypothesized that this diet would increase cardiovascular monitor urinary ketones daily with urine reagent strips, and risk as assessed by the serum lipid profile. these logs were reviewed biweekly with an investigator. Sub- jects in both groups were recommended to perform 30 min- METHODS utes of aerobic exercise 3 times per week, although they were With the use of an institutional review board–approved not requested to record their exercise. protocol, participants were recruited from patients 12 to 18 The LF diet was used as the comparison diet because it years of age who were referred to the Center for Atherosclero- is consistent with standard-of-care for the treatment of pedi- sis Prevention of Schneider Children’s Hospital by their pedi- atric obesity and has been documented as a successful method atricians for weight management. All participants resided in of intervention.15,27,28 In fact, most expert groups recommend the New York City suburban area. Patients who had primary LF diets with elimination of simple sugars and reduction of obesity with a BMI >95th percentile for age were screened starches and complex carbohydrate and self-selected energy and referred for random assignment. As the 95th percentile intake for weight control. We have been using this diet in our for age cutoff is the usually recognized standard for diagnos- weight management program in clinical and research practice ing overweight and obesity, and studies have shown that above for more than 10 years, with both weight loss and lipid profile this BMI percentile adolescents have a significantly higher improvement.15 risk for death caused by obesity,10 these participants were be- The 12-week duration of the study was chosen because lieved to be most able to benefit from the intervention. Pa- previous studies have shown that significant effects of dietary 254 Sondike, Copperman, and Jacobson The Journal of Pediatrics • March 2003 Ta b le II.