Obes Facts 2013;6:469–480 DOI: 10.1159/000355822 Received: November 23, 2012 Accepted: May 25, 2013 Published online: October 11, 2013
© 2013 S. Karger GmbH, Freiburg 1662–4033/13/0065–0469$38.00/0 www.karger.com/ofa
This is an Open Access article licensed under the terms of the Creative Commons AttributionNonCommercial 3.0 Unported license (CC BY-NC) (www.karger.com/OA-license), applicable to the online version of the article only. Distribution permitted for non-commercial purposes only.
Original Article
Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients Julia K. Winkler a Jobst-Hendrik Schultz b Annika Woehning a David Piel a Lena Gartner a Mirjam Hildebrand a Eva Roeder c Peter P. Nawroth a Christian Wolfrum c Gottfried Rudofsky a a
Department of Medicine I and Clinical Chemistry, b Department of General Internal Medicine and Psychosomatics, University of Heidelberg, Heidelberg, Germany, c Swiss Federal Institute of Technology, Institute of Food Nutrition and Health, ETH Zürich, SLA C94, Schwerzenbach, Switzerland
Key Words Weight loss · Weight maintenance · Weight regain · Obesity · Low calorie diet · Formula diet · Diabetes conversion Abstract Aims: To compare effectiveness of a 1-year weight loss program in moderately and severely obese patients. Methods: The study sample included 311 obese patients participating in a weight loss program, which comprised a 12-week weight reduction phase (low-calorie formula diet) and a 40-week weight maintenance phase. Body weight and glucose and lipid values were determined at the beginning of the program as well as after the weight reduction and the weight maintenance phase. Participants were analyzed according to their BMI class at baseline (30–34.9 kg/m2; 35–39.9 kg/m2; 40–44.9 kg/m2; 45–49.9 kg/m2; ≥50 kg/m2). Furthermore, moderately obese patients (BMI < 40 kg/m2) were compared to severely obese participants (BMI ≥ 40 kg/m2). Results: Out of 311 participants, 217 individuals completed the program. Their mean baseline BMI was 41.8 ± 0.5 kg/m2. Average weight loss was 17.9 ± 0.6%, resulting in a BMI of 34.3 ± 0.4 kg/m2 after 1 year (p < 0.001). Overall weight loss was not significantly different in moderately and severely obese participants. Yet, severely obese participants achieved greater weight loss during the weight maintenance phase than moderately obese participants (–3.1 ± 0.7% vs. –1.2 ± 0.6%; p = 0.04). Improvements in lipid profiles and glucose metabolism were found throughout all BMI classes. Conclusion: 1-year weight loss intervention improves body weight as well as lipid and glucose metabolism not only in moderately, but also in severely obese individuals. © 2013 S. Karger GmbH, Freiburg J.K. Winkler and J.-H. Schultz contributed equally to this work. Gottfried Rudofsky, MD Department of Medicine I and Clinical Chemistry University of Heidelberg Im Neuenheimer Feld 410, 69120 Heidelberg (Germany) gottfried_rudofsky @ med.uni-heidelberg.de
470
Obes Facts 2013;6:469–480 DOI: 10.1159/000355822
© 2013 S. Karger GmbH, Freiburg www.karger.com/ofa
Winkler et al.: Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients
Introduction
Obesity has become a worldwide epidemic and a serious global health issue [1–3]. According to the World Health Organization (WHO), obesity more than doubled worldwide since 1980 [4]. In 2008, 1.5 billion adults were overweight [4]. Of these, nearly 300 million women and more than 200 million men were obese [4]. In the past years, the prevalence of obesity, especially severe obesity (BMI ≥ 40 kg/m2), has increased [5]. Severe obesity is frequently accompanied by various obesity-related health issues, e.g. type 2 diabetes, cardiovascular diseases, osteoarthritis and certain types of cancer, and therefore associated with a reduced life expectancy [3, 4, 6]. Hence, promising obesity treatment approaches aiming at body weight reduction and improvement of cardiovascular risk factors such as hyperglycemia and hyperlipidemia are required. However, most commercial weight loss interventions remain unsatisfactory [7]. Particularly in severe obesity, medical treatment approaches are believed to be disappointing [8]. Thus, severely obese patients are often referred to bariatric surgery [9, 10]. Multimodal medically supervised weight loss programs have been suggested as possible treatment option for obesity and obesity-related diseases [11]. So far, the efficacy of such programs in severely obese patients has not been studied extensively. Therefore, our study aimed at comparing weight loss and improvement of cardiovascular risk factors in severely obese (BMI ≥ 40 kg/m2) and moderately obese subjects (BMI < 40 kg/m2) during a 1-year medically supervised low-calorie weight loss program (OPTIFAST®52). Material and Methods The Weight Loss Program OPTIFAST®52 The present study was a single-center, longitudinal investigation including obese participants of the multidisciplinary, non-surgical weight loss program OPTIFAST®52 (franchise holder Nestlé Inc., Vevey, Switzerland). It was established in Germany in 1999 to treat obese individuals of at least 18 years of age and a minimum BMI of 30 kg/m2. Patients with different states of glucose intolerance are included. Patients suffering from an eating disorder may not participate in the program. There were no further inclusion or exclusion criteria. OPTIFAST®52 is a 1-year lifestyle modification program including five different phases and four modules (psychology, medicine, dietetics and exercise). It is implemented by qualified health professionals including psychologists, physicians, nutritionists, and physical therapists [11]. During the program, closed groups of 8–15 persons meet weekly for about 3.5 h per session. The five phases include a 1-week introduction and a 12-week period of low-calorie diet (LCD, Optifast 800 formula, Nestlé Inc.; 800 kcal/day with 70 g protein, 15 g fat and 100 g carbohydrates). During this time, participants consume five packages of formula diet per day (160 kcal each, dissolved in 300 ml water). This phase is accompanied by 12 medical examinations, 12 exercise units, 2 behavior therapy lessons, and 2 nutrition counselings. In the analysis presented here, these two phases are referred to as weight reduction phase (T0–T1) since in this period the most pronounced weight loss occurs. It is followed by a 6-week refeeding phase in which solid food is reintroduced and stepwise replaces formula diet without change of total calorie intake. This phase is accompanied by 6 medical examinations, 6 exercise units, 2 behavior therapy lessons, and 6 nutrition counselings. Subsequently, a 7-week stabilization phase follows in which energy intake is stepwise enhanced to an individual level. The steps are predefined according to the program instructions: Step 1 accounts for approximately 1,200 kcal/day, step 2 for 1,400 kcal/day, step 3 for 1,600 kcal/day, step 4 for 1,800 kcal/day, and step 5 for 2,000 kca/day. Determination of the individual level is based on current weight, daily physical activity, and the further goals of each participant. Dietary intake is controlled by a point-based system. Points refer to protein, carbohydrate and fat content of the consumed food. This stabilization phase is accompanied by 3 medical examinations, 4 exercise units, 4 behavior therapy lessons, and 3 nutrition counselings. A 26-week maintenance phase follows, in which nutritional education and behavior modification is intensified to acquire strategies to cope with e.g. stress or frustration and to establish new reward strategies in order to achieve long-term weight control. Again, it is accompanied by 6 medical examinations, 13 exercise units, 22 behavior therapy lessons, and 5 nutrition counselings. In the current analysis the refeeding, stabilization and maintenance phases are summarized as weight maintenance phase (T1–T2).
471
Obes Facts 2013;6:469–480 DOI: 10.1159/000355822
© 2013 S. Karger GmbH, Freiburg www.karger.com/ofa
Winkler et al.: Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients
Altogether, treatment during the program is similar throughout all BMI categories. In this study, data was included from the beginning of the program (T0), from week 12 after the weight reduction phase (T1), and from week 52 after the weight maintenance phase (T2). Study Collective The ethics committee at the University of Heidelberg approved the study, and all participants gave written informed consent. The study sample included 311 obese individuals participating in the weight loss program at the Obesity Center of the University Hospital of Heidelberg between 2004 and 2011. Participants were grouped according to their baseline BMI (30.0–34.9 kg/m2; 35.0–39.9 kg/m2; 40.0–44.9 kg/m2; 45.0– 49.9 kg/m2; ≥50.0 kg/m2). Participants with an initial BMI of 30.0–39.9 kg/m2 were classified as moderately obese and compared to the group of severely obese participants (BMI ≥ 40.0 kg/m2), which included super obese subjects with a BMI ≥ 50.0 kg/m2. At the end of the program, subjects with a BMI of 25.0–29.9 kg/m2 were classified as overweight and subjects with a BMI < 25.0 kg/m2 as normal-weight. Of the 311 participants, 47 suffered from overt diabetes at baseline. Out of these patients, 13 were treated with dietary intervention, 27 were treated with oral antidiabetic drugs, and 7 patients received a basal or intensified insulin therapy. Anthropometric and Laboratory Measurements During the 1-year program, body weight was monitored weekly on a calibrated scale (Seca 764, Hamburg, Germany) after an 8-hour fast. BMI was calculated as weight (kg) divided by the square of the height (m). Moreover, systolic and diastolic blood pressure was assessed regularly. Blood samples were taken three times during the program each after a fasting time of at least 8 h. Parameters from the beginning (T0) and the end of the 1-year program (T2) were included in the analysis. Concentrations of blood glucose, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides were measured in the central laboratory of the University Hospital of Heidelberg. Glucose levels were assessed from blood collection tubes containing sodium fluoride and lipid parameters were measured from lithium heparin tubes. Separated plasma was analyzed on a Siemens ADVIA® 2400 chemistry analyzer. Siemens test kits were used according to the manufacturer’s instruction to measure the concentrations of glucose, total cholesterol, HDL cholesterol, and triglycerides. Moreover, the Friedewald equation was applied to assess the concentration of LDL cholesterol. Diagnosis of Impaired Glucose Metabolism and Diabetes Diagnosis of type 2 diabetes was based on the fasting glucose levels and the results of an oral glucose tolerance test (OGTT), which was introduced in the OPTIFAST®52 program in 2006. Impaired fasting glucose (IFG, fasting glucose levels: 110–125 mg/dl), impaired glucose tolerance (IGT, glucose levels in 2-hour OGTT: 140–199 mg/dl) and type 2 diabetes (fasting glucose levels ≥ 126 mg/dl, glucose levels in 2-hour OGTT ≥ 200 mg/dl) were defined according to the WHO criteria [12]. HOMA (homeostasis model assessment) index was calculated as: Insulin (μU/ml) × glucose (mmol/l) / 22.5. Statistical Analysis A per-protocol analysis including only subjects who completed the whole program was chosen to study the efficacy of the OPTIFAST®52 program on weight reduction, lipid improvement, and diabetes remission. Data analysis was performed with Microsoft Excel Version 2007 and SPSS Version 18.0. Variables are depicted as means ± standard error of the mean (SEM) or percentages. Statistical significance was calculated with a two-sided t-test and chi-square (χ2) test. Furthermore, a multiple regression analysis was conducted with covariates (gender, age (years), diabetes, hypertension, BMI at T0 (kg/m2)) for adjustment of potential confounding. A p value < 0.05 was assumed to be statistically significant.
Results
The 1-year weight loss program was completed by 217 of the 311 participants while 94 terminated prematurely, which corresponds to an attrition rate of 30.2%. The attrition rate was nearly similar for moderately (28.3%) and severely obese patients (31.5%; p = 0.58). Baseline characteristics of the completers are summarized in table 1. Furthermore, table 2
472
Obes Facts 2013;6:469–480 © 2013 S. Karger GmbH, Freiburg www.karger.com/ofa
DOI: 10.1159/000355822
Winkler et al.: Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients
Table 1. Baseline characteristics are depicted for all completers (n = 217) and according to their initial BMI classa
All
Total
Age, years Sex F/M, n Height, m Weight, kg BMI, kg/m2 Total cholesterol, mg/dl LDL cholesterol, mg/dl HDL cholesterol, mg/dl Triacylglycerols, mg/dl Glucose, mg/dl HOMA-IR Systolic blood pressure, mm Hg Diastolic blood pressure mm Hg Lipid lowering agents, % Antidiabetic agents, % Antihypertensive medication, % Antipsychotic drugs, %
Men
Age, years Height, m Weight, kg BMI, kg/m2 Total cholesterol, mg/dl LDL cholesterol, mg/dl HDL cholesterol, mg/dl Triacylglycerols, mg/dl Glucose, mg/dl HOMA-IR Systolic blood pressure, mm Hg Diastolic blood pressure mm Hg Lipid lowering agents, % Antidiabetic agents, % Antihypertensive medication, % Antipsychotic drugs, %
Women
Age, years Height, m Weight, kg BMI, kg/m2 Total cholesterol, mg/dl LDL cholesterol, mg/dl HDL cholesterol, mg/dl Triacylglycerols, mg/dl Glucose, mg/dl HOMA-IR Systolic blood pressure, mm Hg Diastolic blood pressure mm Hg Lipid lowering agents, % Antidiabetic agents, % Antihypertensive medication, % Antipsychotic drugs, %
BMI, kg/m2 30 – 34.9
35 – 39.9
40 – 44.9
45 – 49.9
BMI ≥ 50
44.7 ± 0.8 142 / 75 1.71 ± 0.01 122.8 ± 1.6 41.8 ± 0.5 201 ± 3 122 ± 2 50 ± 1 145 ± 6 107 ± 2 7.1 ± 0.6 140 ± 1 89 ± 1 9.3 17.2 43.8 11.5
45.8 ± 2.0 22 / 9 1.71 ± 0.02 97.3 ± 2.1 33.3 ± 0.2 221 ± 8 134 ± 8 53 ± 2 163 ± 19 99 ± 3 4.9 ± 0.9 135 ± 3 87 ± 2 16.1 4.2 25.8 6.5
45.9 ± 1.4 44 / 27 1.72 ± 0.01 111.9 ± 1.4 37.6 ± 0.2 202 ± 5 123 ± 4 51 ± 2 143 ± 10 105 ± 3 5.3 ± 0.4 139 ± 2 89 ± 1 9.9 15.9 38.0 12.7
44.3 ± 1.7 37 / 15 1.70 ± 0.01 124.1 ± 2.0 42.6 ± 0.2 202 ± 5 123 ± 5 49 ± 1 151 ± 11 110 ± 5 8.4 ± 1.9 140 ± 3 89 ± 2 7.7 17.4 42.3 9.6
43.4 ± 1.9 29 / 10 1.70 ± 0.01 136.5 ± 2.2 47.1 ± 0.2 196 ± 5 117 ± 4 52 ± 2 135 ± 11 106 ± 4 9.1 ± 2.3 142 ± 2 89 ± 2 5.3 21.6 61.5 17.9
42.5 ± 1.8 10 / 14 1.72 ± 0.02 162.7 ± 5.8 54.5 ± 1.1 174 ± 7 107 ± 6 42 ± 2 129 ± 7 115 ± 8 9.1 ± 1.3 142 ± 4 88 ± 2 8.3 27.3 58.3 8.3
45.9 ± 1.4 1.79 ± 0.01 136.5 ± 3.1 42.7 ± 0.9 203 ± 5 121 ± 4 45 ± 1 184 ± 12 113 ± 5 7.8 ± 0.9 144 ± 2 90 ± 1 16.0 22.4 46.7 9.3
48.0 ± 3.1 1.79 ± 0.03 107.6 ± 3.5 33.6 ± 0.3 236 ± 14 129 ± 17 44 ± 2 285 ± 41 101 ± 5 8.3 ± 2.5 137 ± 5 85 ± 3 11.1 0 0 0
47.4 ± 2.7 1.80 ± 0.02 121.1 ± 2.4 37.4 ± 0.3 207 ± 8 123 ± 6 48 ± 2 178 ± 23 113 ± 8 6.0 ± 0.6 143 ± 3 92 ± 2 18.5 32 44.4 14.8
44.6 ± 2.9 1.80 ± 0.01 139.7 ± 1.9 43.1 ± 0.3 209 ± 12 129 ± 11 43 ± 2 192 ± 28 124 ± 14 6.2 ± 1.6 146 ± 5 89 ± 3 20 14.3 53.3 6.7
42.1 ± 4.2 1.79 ± 0.03 149.8 ± 4.6 46.9 ± 0.4 197 ± 10 112 ± 10 46 ± 5 186 ± 29 105 ± 7 12.3 ± 4.6 150 ± 4 91 ± 4 10 30 60 10
45.8 ± 1.8 1.75 ± 0.03 171.6 ± 8.6 55.3 ± 1.6 175 ± 9 110 ± 7.3 41 ± 2 126 ± 9 113 ± 13 9.2 ± 1.7 142 ± 6 89 ± 3 14.3 16.7 64.3 7.1
44.0 ± 1.0 1.67 ± 0.01 115.6 ± 1.6 41.3 ± 0.5 199 ± 3 122 ± 3 53 ± 1 125 ± 4 103 ± 2 6.7 ± 0.9 137 ± 1 88 ± 1 5.7 14.4 42.3 12.7
44.9 ± 2.6 1.67 ± 0.02 93.1 ± 2.1 33.2 ± 0.3 214 ± 10 135 ± 10 56 ± 3 119 ± 11 99 ± 4 3.9 ± 0.6 134 ± 3 88 ± 2 18.2 5.6 36.4 9.1
45.0 ± 1.6 1.68 ± 0.01 106.3 ± 1.2 37.7 ± 0.2 199 ± 6 123 ± 4 53 ± 2 121 ± 8 100 ± 3 4.9 ± 0.5 136 ± 3 87 ± 2 4.5 5.3 34.1 11.4
44.1 ± 2.1 1.67 ± 0.01 117.7 ± 1.8 42.4 ± 0.2 200 ± 6 121 ± 6 51 ± 2 134 ± 9 104 ± 4 9.3 ± 2.5 138 ± 3 89 ± 2 2.7 18.8 37.8 10.8
43.8 ± 2.1 1.67 ± 0.01 132.0 ± 1.9 47.2 ± 0.2 196 ± 6 118 ± 4 54 ± 2 119 ± 10 106 ± 5 7.7 ± 2.7 139 ± 3 88 ± 2 3.6 18.5 62.1 20.7
37.8 ± 3.1 1.68 ± 0.02 150.1 ± 5.6 53.3 ± 1.3 173 ± 14 103 ± 11 43 ± 3 134 ± 12 117 ± 5 9.0 ± 2.1 141 ± 6 87 ± 3 0 40 50 10
F = Female; M = male. aMean values ± SEM are given.
473
Obes Facts 2013;6:469–480 © 2013 S. Karger GmbH, Freiburg www.karger.com/ofa
DOI: 10.1159/000355822
Winkler et al.: Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients
Table 2. Baseline characteristics are depicted for the completers of the program with a BMI < 40 kg/m2 and those with a BMI ≥ 40 kg/m2 a
BMI, kg/m2
Age, years Sex F/M, n Height, m Weight, kg BMI, kg/m2 Total cholesterol, mg/dl LDL cholesterol, mg/dl HDL cholesterol, mg/dl Triacylglycerols, mg/dl Glucose, mg/dl HOMA-IR Systolic blood pressure, mm Hg Diastolic blood pressure, mm Hg Lipid lowering agents, % Antidiabetic agents, % Antihypertensive medication, % Antipsychotic drugs, %
© 2013 S. Karger GmbH, Freiburg 1662–4033/13/0065–0469$38.00/0 www.karger.com/ofa
This is an Open Access article licensed under the terms of the Creative Commons AttributionNonCommercial 3.0 Unported license (CC BY-NC) (www.karger.com/OA-license), applicable to the online version of the article only. Distribution permitted for non-commercial purposes only.
Original Article
Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients Julia K. Winkler a Jobst-Hendrik Schultz b Annika Woehning a David Piel a Lena Gartner a Mirjam Hildebrand a Eva Roeder c Peter P. Nawroth a Christian Wolfrum c Gottfried Rudofsky a a
Department of Medicine I and Clinical Chemistry, b Department of General Internal Medicine and Psychosomatics, University of Heidelberg, Heidelberg, Germany, c Swiss Federal Institute of Technology, Institute of Food Nutrition and Health, ETH Zürich, SLA C94, Schwerzenbach, Switzerland
Key Words Weight loss · Weight maintenance · Weight regain · Obesity · Low calorie diet · Formula diet · Diabetes conversion Abstract Aims: To compare effectiveness of a 1-year weight loss program in moderately and severely obese patients. Methods: The study sample included 311 obese patients participating in a weight loss program, which comprised a 12-week weight reduction phase (low-calorie formula diet) and a 40-week weight maintenance phase. Body weight and glucose and lipid values were determined at the beginning of the program as well as after the weight reduction and the weight maintenance phase. Participants were analyzed according to their BMI class at baseline (30–34.9 kg/m2; 35–39.9 kg/m2; 40–44.9 kg/m2; 45–49.9 kg/m2; ≥50 kg/m2). Furthermore, moderately obese patients (BMI < 40 kg/m2) were compared to severely obese participants (BMI ≥ 40 kg/m2). Results: Out of 311 participants, 217 individuals completed the program. Their mean baseline BMI was 41.8 ± 0.5 kg/m2. Average weight loss was 17.9 ± 0.6%, resulting in a BMI of 34.3 ± 0.4 kg/m2 after 1 year (p < 0.001). Overall weight loss was not significantly different in moderately and severely obese participants. Yet, severely obese participants achieved greater weight loss during the weight maintenance phase than moderately obese participants (–3.1 ± 0.7% vs. –1.2 ± 0.6%; p = 0.04). Improvements in lipid profiles and glucose metabolism were found throughout all BMI classes. Conclusion: 1-year weight loss intervention improves body weight as well as lipid and glucose metabolism not only in moderately, but also in severely obese individuals. © 2013 S. Karger GmbH, Freiburg J.K. Winkler and J.-H. Schultz contributed equally to this work. Gottfried Rudofsky, MD Department of Medicine I and Clinical Chemistry University of Heidelberg Im Neuenheimer Feld 410, 69120 Heidelberg (Germany) gottfried_rudofsky @ med.uni-heidelberg.de
470
Obes Facts 2013;6:469–480 DOI: 10.1159/000355822
© 2013 S. Karger GmbH, Freiburg www.karger.com/ofa
Winkler et al.: Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients
Introduction
Obesity has become a worldwide epidemic and a serious global health issue [1–3]. According to the World Health Organization (WHO), obesity more than doubled worldwide since 1980 [4]. In 2008, 1.5 billion adults were overweight [4]. Of these, nearly 300 million women and more than 200 million men were obese [4]. In the past years, the prevalence of obesity, especially severe obesity (BMI ≥ 40 kg/m2), has increased [5]. Severe obesity is frequently accompanied by various obesity-related health issues, e.g. type 2 diabetes, cardiovascular diseases, osteoarthritis and certain types of cancer, and therefore associated with a reduced life expectancy [3, 4, 6]. Hence, promising obesity treatment approaches aiming at body weight reduction and improvement of cardiovascular risk factors such as hyperglycemia and hyperlipidemia are required. However, most commercial weight loss interventions remain unsatisfactory [7]. Particularly in severe obesity, medical treatment approaches are believed to be disappointing [8]. Thus, severely obese patients are often referred to bariatric surgery [9, 10]. Multimodal medically supervised weight loss programs have been suggested as possible treatment option for obesity and obesity-related diseases [11]. So far, the efficacy of such programs in severely obese patients has not been studied extensively. Therefore, our study aimed at comparing weight loss and improvement of cardiovascular risk factors in severely obese (BMI ≥ 40 kg/m2) and moderately obese subjects (BMI < 40 kg/m2) during a 1-year medically supervised low-calorie weight loss program (OPTIFAST®52). Material and Methods The Weight Loss Program OPTIFAST®52 The present study was a single-center, longitudinal investigation including obese participants of the multidisciplinary, non-surgical weight loss program OPTIFAST®52 (franchise holder Nestlé Inc., Vevey, Switzerland). It was established in Germany in 1999 to treat obese individuals of at least 18 years of age and a minimum BMI of 30 kg/m2. Patients with different states of glucose intolerance are included. Patients suffering from an eating disorder may not participate in the program. There were no further inclusion or exclusion criteria. OPTIFAST®52 is a 1-year lifestyle modification program including five different phases and four modules (psychology, medicine, dietetics and exercise). It is implemented by qualified health professionals including psychologists, physicians, nutritionists, and physical therapists [11]. During the program, closed groups of 8–15 persons meet weekly for about 3.5 h per session. The five phases include a 1-week introduction and a 12-week period of low-calorie diet (LCD, Optifast 800 formula, Nestlé Inc.; 800 kcal/day with 70 g protein, 15 g fat and 100 g carbohydrates). During this time, participants consume five packages of formula diet per day (160 kcal each, dissolved in 300 ml water). This phase is accompanied by 12 medical examinations, 12 exercise units, 2 behavior therapy lessons, and 2 nutrition counselings. In the analysis presented here, these two phases are referred to as weight reduction phase (T0–T1) since in this period the most pronounced weight loss occurs. It is followed by a 6-week refeeding phase in which solid food is reintroduced and stepwise replaces formula diet without change of total calorie intake. This phase is accompanied by 6 medical examinations, 6 exercise units, 2 behavior therapy lessons, and 6 nutrition counselings. Subsequently, a 7-week stabilization phase follows in which energy intake is stepwise enhanced to an individual level. The steps are predefined according to the program instructions: Step 1 accounts for approximately 1,200 kcal/day, step 2 for 1,400 kcal/day, step 3 for 1,600 kcal/day, step 4 for 1,800 kcal/day, and step 5 for 2,000 kca/day. Determination of the individual level is based on current weight, daily physical activity, and the further goals of each participant. Dietary intake is controlled by a point-based system. Points refer to protein, carbohydrate and fat content of the consumed food. This stabilization phase is accompanied by 3 medical examinations, 4 exercise units, 4 behavior therapy lessons, and 3 nutrition counselings. A 26-week maintenance phase follows, in which nutritional education and behavior modification is intensified to acquire strategies to cope with e.g. stress or frustration and to establish new reward strategies in order to achieve long-term weight control. Again, it is accompanied by 6 medical examinations, 13 exercise units, 22 behavior therapy lessons, and 5 nutrition counselings. In the current analysis the refeeding, stabilization and maintenance phases are summarized as weight maintenance phase (T1–T2).
471
Obes Facts 2013;6:469–480 DOI: 10.1159/000355822
© 2013 S. Karger GmbH, Freiburg www.karger.com/ofa
Winkler et al.: Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients
Altogether, treatment during the program is similar throughout all BMI categories. In this study, data was included from the beginning of the program (T0), from week 12 after the weight reduction phase (T1), and from week 52 after the weight maintenance phase (T2). Study Collective The ethics committee at the University of Heidelberg approved the study, and all participants gave written informed consent. The study sample included 311 obese individuals participating in the weight loss program at the Obesity Center of the University Hospital of Heidelberg between 2004 and 2011. Participants were grouped according to their baseline BMI (30.0–34.9 kg/m2; 35.0–39.9 kg/m2; 40.0–44.9 kg/m2; 45.0– 49.9 kg/m2; ≥50.0 kg/m2). Participants with an initial BMI of 30.0–39.9 kg/m2 were classified as moderately obese and compared to the group of severely obese participants (BMI ≥ 40.0 kg/m2), which included super obese subjects with a BMI ≥ 50.0 kg/m2. At the end of the program, subjects with a BMI of 25.0–29.9 kg/m2 were classified as overweight and subjects with a BMI < 25.0 kg/m2 as normal-weight. Of the 311 participants, 47 suffered from overt diabetes at baseline. Out of these patients, 13 were treated with dietary intervention, 27 were treated with oral antidiabetic drugs, and 7 patients received a basal or intensified insulin therapy. Anthropometric and Laboratory Measurements During the 1-year program, body weight was monitored weekly on a calibrated scale (Seca 764, Hamburg, Germany) after an 8-hour fast. BMI was calculated as weight (kg) divided by the square of the height (m). Moreover, systolic and diastolic blood pressure was assessed regularly. Blood samples were taken three times during the program each after a fasting time of at least 8 h. Parameters from the beginning (T0) and the end of the 1-year program (T2) were included in the analysis. Concentrations of blood glucose, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides were measured in the central laboratory of the University Hospital of Heidelberg. Glucose levels were assessed from blood collection tubes containing sodium fluoride and lipid parameters were measured from lithium heparin tubes. Separated plasma was analyzed on a Siemens ADVIA® 2400 chemistry analyzer. Siemens test kits were used according to the manufacturer’s instruction to measure the concentrations of glucose, total cholesterol, HDL cholesterol, and triglycerides. Moreover, the Friedewald equation was applied to assess the concentration of LDL cholesterol. Diagnosis of Impaired Glucose Metabolism and Diabetes Diagnosis of type 2 diabetes was based on the fasting glucose levels and the results of an oral glucose tolerance test (OGTT), which was introduced in the OPTIFAST®52 program in 2006. Impaired fasting glucose (IFG, fasting glucose levels: 110–125 mg/dl), impaired glucose tolerance (IGT, glucose levels in 2-hour OGTT: 140–199 mg/dl) and type 2 diabetes (fasting glucose levels ≥ 126 mg/dl, glucose levels in 2-hour OGTT ≥ 200 mg/dl) were defined according to the WHO criteria [12]. HOMA (homeostasis model assessment) index was calculated as: Insulin (μU/ml) × glucose (mmol/l) / 22.5. Statistical Analysis A per-protocol analysis including only subjects who completed the whole program was chosen to study the efficacy of the OPTIFAST®52 program on weight reduction, lipid improvement, and diabetes remission. Data analysis was performed with Microsoft Excel Version 2007 and SPSS Version 18.0. Variables are depicted as means ± standard error of the mean (SEM) or percentages. Statistical significance was calculated with a two-sided t-test and chi-square (χ2) test. Furthermore, a multiple regression analysis was conducted with covariates (gender, age (years), diabetes, hypertension, BMI at T0 (kg/m2)) for adjustment of potential confounding. A p value < 0.05 was assumed to be statistically significant.
Results
The 1-year weight loss program was completed by 217 of the 311 participants while 94 terminated prematurely, which corresponds to an attrition rate of 30.2%. The attrition rate was nearly similar for moderately (28.3%) and severely obese patients (31.5%; p = 0.58). Baseline characteristics of the completers are summarized in table 1. Furthermore, table 2
472
Obes Facts 2013;6:469–480 © 2013 S. Karger GmbH, Freiburg www.karger.com/ofa
DOI: 10.1159/000355822
Winkler et al.: Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients
Table 1. Baseline characteristics are depicted for all completers (n = 217) and according to their initial BMI classa
All
Total
Age, years Sex F/M, n Height, m Weight, kg BMI, kg/m2 Total cholesterol, mg/dl LDL cholesterol, mg/dl HDL cholesterol, mg/dl Triacylglycerols, mg/dl Glucose, mg/dl HOMA-IR Systolic blood pressure, mm Hg Diastolic blood pressure mm Hg Lipid lowering agents, % Antidiabetic agents, % Antihypertensive medication, % Antipsychotic drugs, %
Men
Age, years Height, m Weight, kg BMI, kg/m2 Total cholesterol, mg/dl LDL cholesterol, mg/dl HDL cholesterol, mg/dl Triacylglycerols, mg/dl Glucose, mg/dl HOMA-IR Systolic blood pressure, mm Hg Diastolic blood pressure mm Hg Lipid lowering agents, % Antidiabetic agents, % Antihypertensive medication, % Antipsychotic drugs, %
Women
Age, years Height, m Weight, kg BMI, kg/m2 Total cholesterol, mg/dl LDL cholesterol, mg/dl HDL cholesterol, mg/dl Triacylglycerols, mg/dl Glucose, mg/dl HOMA-IR Systolic blood pressure, mm Hg Diastolic blood pressure mm Hg Lipid lowering agents, % Antidiabetic agents, % Antihypertensive medication, % Antipsychotic drugs, %
BMI, kg/m2 30 – 34.9
35 – 39.9
40 – 44.9
45 – 49.9
BMI ≥ 50
44.7 ± 0.8 142 / 75 1.71 ± 0.01 122.8 ± 1.6 41.8 ± 0.5 201 ± 3 122 ± 2 50 ± 1 145 ± 6 107 ± 2 7.1 ± 0.6 140 ± 1 89 ± 1 9.3 17.2 43.8 11.5
45.8 ± 2.0 22 / 9 1.71 ± 0.02 97.3 ± 2.1 33.3 ± 0.2 221 ± 8 134 ± 8 53 ± 2 163 ± 19 99 ± 3 4.9 ± 0.9 135 ± 3 87 ± 2 16.1 4.2 25.8 6.5
45.9 ± 1.4 44 / 27 1.72 ± 0.01 111.9 ± 1.4 37.6 ± 0.2 202 ± 5 123 ± 4 51 ± 2 143 ± 10 105 ± 3 5.3 ± 0.4 139 ± 2 89 ± 1 9.9 15.9 38.0 12.7
44.3 ± 1.7 37 / 15 1.70 ± 0.01 124.1 ± 2.0 42.6 ± 0.2 202 ± 5 123 ± 5 49 ± 1 151 ± 11 110 ± 5 8.4 ± 1.9 140 ± 3 89 ± 2 7.7 17.4 42.3 9.6
43.4 ± 1.9 29 / 10 1.70 ± 0.01 136.5 ± 2.2 47.1 ± 0.2 196 ± 5 117 ± 4 52 ± 2 135 ± 11 106 ± 4 9.1 ± 2.3 142 ± 2 89 ± 2 5.3 21.6 61.5 17.9
42.5 ± 1.8 10 / 14 1.72 ± 0.02 162.7 ± 5.8 54.5 ± 1.1 174 ± 7 107 ± 6 42 ± 2 129 ± 7 115 ± 8 9.1 ± 1.3 142 ± 4 88 ± 2 8.3 27.3 58.3 8.3
45.9 ± 1.4 1.79 ± 0.01 136.5 ± 3.1 42.7 ± 0.9 203 ± 5 121 ± 4 45 ± 1 184 ± 12 113 ± 5 7.8 ± 0.9 144 ± 2 90 ± 1 16.0 22.4 46.7 9.3
48.0 ± 3.1 1.79 ± 0.03 107.6 ± 3.5 33.6 ± 0.3 236 ± 14 129 ± 17 44 ± 2 285 ± 41 101 ± 5 8.3 ± 2.5 137 ± 5 85 ± 3 11.1 0 0 0
47.4 ± 2.7 1.80 ± 0.02 121.1 ± 2.4 37.4 ± 0.3 207 ± 8 123 ± 6 48 ± 2 178 ± 23 113 ± 8 6.0 ± 0.6 143 ± 3 92 ± 2 18.5 32 44.4 14.8
44.6 ± 2.9 1.80 ± 0.01 139.7 ± 1.9 43.1 ± 0.3 209 ± 12 129 ± 11 43 ± 2 192 ± 28 124 ± 14 6.2 ± 1.6 146 ± 5 89 ± 3 20 14.3 53.3 6.7
42.1 ± 4.2 1.79 ± 0.03 149.8 ± 4.6 46.9 ± 0.4 197 ± 10 112 ± 10 46 ± 5 186 ± 29 105 ± 7 12.3 ± 4.6 150 ± 4 91 ± 4 10 30 60 10
45.8 ± 1.8 1.75 ± 0.03 171.6 ± 8.6 55.3 ± 1.6 175 ± 9 110 ± 7.3 41 ± 2 126 ± 9 113 ± 13 9.2 ± 1.7 142 ± 6 89 ± 3 14.3 16.7 64.3 7.1
44.0 ± 1.0 1.67 ± 0.01 115.6 ± 1.6 41.3 ± 0.5 199 ± 3 122 ± 3 53 ± 1 125 ± 4 103 ± 2 6.7 ± 0.9 137 ± 1 88 ± 1 5.7 14.4 42.3 12.7
44.9 ± 2.6 1.67 ± 0.02 93.1 ± 2.1 33.2 ± 0.3 214 ± 10 135 ± 10 56 ± 3 119 ± 11 99 ± 4 3.9 ± 0.6 134 ± 3 88 ± 2 18.2 5.6 36.4 9.1
45.0 ± 1.6 1.68 ± 0.01 106.3 ± 1.2 37.7 ± 0.2 199 ± 6 123 ± 4 53 ± 2 121 ± 8 100 ± 3 4.9 ± 0.5 136 ± 3 87 ± 2 4.5 5.3 34.1 11.4
44.1 ± 2.1 1.67 ± 0.01 117.7 ± 1.8 42.4 ± 0.2 200 ± 6 121 ± 6 51 ± 2 134 ± 9 104 ± 4 9.3 ± 2.5 138 ± 3 89 ± 2 2.7 18.8 37.8 10.8
43.8 ± 2.1 1.67 ± 0.01 132.0 ± 1.9 47.2 ± 0.2 196 ± 6 118 ± 4 54 ± 2 119 ± 10 106 ± 5 7.7 ± 2.7 139 ± 3 88 ± 2 3.6 18.5 62.1 20.7
37.8 ± 3.1 1.68 ± 0.02 150.1 ± 5.6 53.3 ± 1.3 173 ± 14 103 ± 11 43 ± 3 134 ± 12 117 ± 5 9.0 ± 2.1 141 ± 6 87 ± 3 0 40 50 10
F = Female; M = male. aMean values ± SEM are given.
473
Obes Facts 2013;6:469–480 © 2013 S. Karger GmbH, Freiburg www.karger.com/ofa
DOI: 10.1159/000355822
Winkler et al.: Effectiveness of a Low-Calorie Weight Loss Program in Moderately and Severely Obese Patients
Table 2. Baseline characteristics are depicted for the completers of the program with a BMI < 40 kg/m2 and those with a BMI ≥ 40 kg/m2 a
BMI, kg/m2
Age, years Sex F/M, n Height, m Weight, kg BMI, kg/m2 Total cholesterol, mg/dl LDL cholesterol, mg/dl HDL cholesterol, mg/dl Triacylglycerols, mg/dl Glucose, mg/dl HOMA-IR Systolic blood pressure, mm Hg Diastolic blood pressure, mm Hg Lipid lowering agents, % Antidiabetic agents, % Antihypertensive medication, % Antipsychotic drugs, %
