The changed living conditions and associated behaviors in the Western world have in many cases overridden previously successful basic biological principles. The consequence, which is visible to everyone and a source of suffering for many, is a loss of health literacy and responsibility, clearly recognizable in the dramatic increase in obesity and its secondary diseases [22, 24]. There appears to be only one comprehensive and effective solution to the problem of obesity: A permanent change in dietary and activity behavior towards an energetically balanced lifestyle while improving diet quality. Against this background, various intervention approaches for weight reduction were compared in terms of their effectiveness in a controlled, randomized study. The aim of the study was, on the one hand, to demonstrate the feasibility of weight and fat mass reduction using a model approach to energy balance. On the other hand, scientific and practical experience in the care of overweight adults was to be gathered in order to develop a standardized intervention program for the treatment of obesity and its associated risk factors.

Methodology

Test subjects

Of 522 interested, overweight participants, 202 potential participants were screened (clinical examination, exercise ECG, laboratory status), taking into account the inclusion and exclusion criteria1 defined in the protocol. Subsequently, 30 participants were randomly assigned to each of the three intervention groups (Fig. 1):
■ Group 1: diet-induced weight loss (D group),
■ Group 2: weight loss induced by diet and exercise (D+S group),
■ Group 3: weight loss induced by health education (GU group).
Four of the allocated participants dropped out at the beginning of the study as they were dissatisfied with their group allocation. Three other participants dropped out of the study for personal reasons. The personal and anthropometric data of the study participants are shown in Table 1. A statistical comparison of the personal characteristics showed no differences for the respective subjects in the intervention groups. For 83 participants, the planned six-month examination could be carried out after 24 weeks. All participants took part in the study voluntarily and with written informed consent. They did not receive any remuneration or financial benefits (success or participation fee). The study was conducted with the approval of the ethics committee of the medical faculty of the Freiburg University Hospital.

Health classes, diet and sports program

All participants were informed in detail about the basic procedure, the content and objectives of the intervention and the importance of weight reduction. The target criterion agreed with them was to reduce their individual BMI value by 2.5 units. This was to be achieved by specifically changing the daily energy balance. The participants in the "health education" group were also motivated in the form of group and individual counseling sessions to reduce their weight by changing their lifestyle habits. The given everyday conditions were taken into account. The direct contact persons were an adult educator specializing in health and the investigator accompanying the study. The aim of the consultations was to teach and practically implement healthy eating and exercise habits on a self-responsible basis. To this end, teaching materials from the German Nutrition Society (DGE), the German Society for Sports Medicine and Prevention (DGSP) and selected commercially available brochures on the topic of "Health promotion through nutrition and sport" were used. A total of 5 clinical visits, 3 group sessions of 90 minutes each and 2 individual consultations of 20 minutes each were carried out at 6-week intervals.

The participants in the "diet" group were to achieve their BMI target value by eating a calorie-reduced diet. According to an individual, body weight-related scheme, a commercially available high-protein food supplement based on soy yoghurt and honey (Almased®; 100 g contains 54.1 g protein, of which 45.0 g soy protein and 8.3 g milk protein, 31.5 g carbohydrates and 0.6 g fat with a calorific value of 96 kcal; calculated on the individual's normal weight, e.g. 70 kg, 45-50 g Almased is fed as a consumption unit per meal) in the first 6 meals. For the first 6 weeks of the intervention two of the planned three daily meals (saving approx. 1400 kcal), in the following 18 weeks one of the usual three daily meals (saving approx. 700 kcal). kcal). In addition, the participants were informed about a "healthy" and active lifestyle and encouraged to reduce the fat content of the freely selectable meals. The reference person for the diet group was the accompanying investigator. As in the health education group, a total of 5 clinical visits were conducted at six-week intervals over a period of 24 weeks for the participants in the diet group. The people in the "Diet and Sport" group were required to take part in an endurance-oriented, regular and supervised sports program of 2 x 60 minutes per week in addition to the contents of the "Diet" group. 

The aim was to achieve a weekly energy turnover of approx. 2,500 kcal/week, corresponding to 30 METh/week, after an introductory phase of 6 weeks in the second part of the intervention (week 7-24) through supervised and self-performed leisure activities. The participants in the "diet and sport" group were also informed about a "healthy" and active lifestyle and were encouraged to reduce the fat content of the freely selectable meals. The reference persons for the "diet and sport" group were a sports instructor and the accompanying investigator. In this group too, in addition to the weekly sports lessons, a total of 5 clinical visits were carried out at six-week intervals over a period of 24 weeks.

Anthropometric and performance-physiological status

At the beginning of the study and after 24 weeks of intervention, the participants' body composition and physical performance were examined. In conclusion to the whole body volume, the body fat percentage was determined and the body fat mass and the fat-free body mass were calculated in analogy to the hydrostatic body density measurement using BodPod® technology [17]. The BodPod® technology enables the exact determination of body volume in a closed system using pressure sensors via the proportion of the individually displaced air volume. In addition, the participants' abdominal and hip circumferences were measured for indirect assessment of abdominal, visceral and subcutaneous fat distribution [25]. Physical performance was documented for all participants at the beginning and after the intervention phase by means of standardized bicycle ergometry [4] (semi-sitting, three-minute exercise levels of 25 watts each, starting at 50 watts) in a defined exercise protocol. The activity and nutritional behavior of the participants was documented in a protocol. Participant satisfaction and acceptance of the program were also evaluated using a questionnaire.

Metabolic status and risk factor profile

Using standardized and previously described clinical-chemical analysis methods [10], all participants were tested at the beginning and after the intervention phase in a fasting state (between 8 and 9 a.m., after 12 hours of abstinence from food, as cubital venous blood sampling) laboratory parameters for the assessment of metabolic regulation (blood glucose, plasma insulin, serum leptin) as well as atherogenic (total, HDL, LDL cholesterol, triglycerides) and inflammatory risk (plasma fibrinogen, serum hsCRP, serum interleukin 6) were determined.

Statistical analysis

Statistical analysis was performed using SPSS 11.0.1. The Wilcoxon test for paired samples was used for intra-individual comparisons between the status before intervention and the status after 24 weeks within the groups. Analyses of variance were performed to test the hypothesis of whether the differences (before/after intervention) differed between the groups. Non-normally distributed variables (CRP, insulin, IL-6) were previously normalized by logarithmic transformation.

Results

Adherence and acceptance of the program

Of the 90 people participating in the study, 83 were successful over 24 weeks with the programs assigned to them and the associated six-month examination. The majority of participants (83%) were very satisfied or satisfied with the program, and all participants (100%) stated that they would recommend the program or the therapy modules used to others or would use them again. In the two diet-supported groups, 80% of the participants described the nutritional supplement used as a noticeable therapeutic aid for them, 15% of the participants were only partially convinced and 5% were not convinced of the benefits of the nutritional supplement. In the exercise-supported diet group, the participants felt that the training program was the most important therapeutic component.

Weight loss and anthropometric variables

All therapy groups showed a significant reduction in body weight and BMI at the end of the 24-week intervention (Tab. 2a). In a group comparison, the diet-supported groups performed significantly better (Tab. 2b). The agreement made with the participants at the start of the intervention was achieved by 12 of the 28 participants in the GU group (43%), by 20 of the 28 participants in the D group (71%) and by 16 of the 27 participants in the (D+S) group (59%). Based on the guidelines of the German Obesity Society (DAG) [12], 71 % of the participants in the GU group, 89 % in the D group and 93 % in the (D+S) group achieved the goal of a 5 % weight reduction. For all groups, the observed weight reduction could be explained by the simultaneous decrease in fat mass (Tab. 2b). In the correlation analysis, a high biological dependency between weight loss (x) and the corresponding reduction in fat-free body mass was not observed in any group. For the diet-supported groups, however, the greater the weight reduction, the greater the reduction in percentage fat and absolute fat mass (Table 2b). The correlation analysis shows a high biological dependency between weight loss (x) and the corresponding reduction in fat mass (y) in all groups (r2 GU group = 0.85; r2 D group = 0.74; r2 D+S group = 0.75). A reduction in lean body mass was not observed in any group. For the diet-supported groups, however, the greater the weight reduction, the greater the reduction in percentage fat and absolute fat mass (Table 2b). Interestingly, this also appears to be significantly reflected in a reduction in hip circumference in the group comparison.

Cardiovascular fitness

The intervention significantly (p = 0.023) improved the ergometrically tested maximum physical performance by 5 % from 155 watts to 163 watts only in the D group. However, this change is not significant in the group comparison. As expected, all groups showed favorable changes in frequency, blood pressure and lactate regulation with the weight loss achieved. For example, the heart rate at rest and during exercise decreased in all groups by 8-10 beats/min (p <0.001), systolic blood pressure by an average of 10 mmHg (p <0.01) and, for the (D+S) group, the lactate value during exercise (75 watt level) also decreased by 0.24 mmol/l (p <0.01).

Metabolic regulation

A highly significant reduction in serum leptin levels was found in all groups after the intervention phase (Tab. 3a); in relation to the respective mean weight loss as ∆Leptin/∆KG, the leptin reduction of 1.7 ng/ml/kg was particularly pronounced in the D group (Tab. 3b). Once the intervention was completed, there were also significant reductions in fasting blood glucose and plasma insulin levels (Tab. 3a,b). However, the decisive factor for the reduction was the respective initial value at the start of the study. In all groups, the (x+s) values for fasting glucose and plasma insulin were also impressively within the clinical-chemical normal range after the intervention.

Risk factor profile

A highly significant reduction in total and LDL cholesterol was found in all groups after the intervention phase (Tab. 3a); however, a reduction in HDL cholesterol in the range of 5-7 mg/dl was also observed with the low-fat and weight-reducing intervention. Parallel to the atherogenic lipid profile, changes in the proinflammatory profile were also observed. Here there were significant improvements in the values for hs-CRP and IL-6 in the diet-supported groups, depending on previously moderately elevated baseline values. However, when comparing the groups, the changes caused by the intervention did not prove to be significantly different in the various groups (Tab. 3b).

Discussion

The controlled and randomized study presented here was conducted with the aim of developing feasible and practical intervention models for the successful treatment of obesity in adults. The results show that this is effectively possible with different approaches, for example according to the principle of calculated calorie balance, by reducing body fat mass. Scientific and practical experience was also gained in the care of overweight adults and in the treatment of obesity and its associated risk factors. 

In terms of an agreed treatment goal (reduction of the BMI value by 2.5 units), good results were achieved with regard to the reduction and stabilization of body weight with a change in diet, personality behavior and physical activity [6, 8, 18, 21, 25, 27]. The findings on body composition for all three groups show that the proportion of fat in the body mass can be reduced with reasonable effort without affecting the fat-free mass. If - as shown for the diet-supported groups - the restriction of calorie and protein intake to values of less than 1000 kcal per day is avoided by offering a low-fat and high-protein diet, an unphysiological, negative nitrogen balance and the undesirable loss of muscle mass that is usually observed can be avoided even with a weight loss in the range of 0.5 kg/week [2, 9, 13]. Intervention programs with an energy deficit of around 700 kcal/day also appear to be medically justifiable in the long term when observing the body composition. Thus, under the conditions investigated here, the maintenance of lean body mass and muscle mass, which is important for basal and energy metabolism, appears to be possible without guided or supervised additional physical activity if a protein source favorable for the nitrogen balance is supplied [20, 29].

If, in addition to body density, the results for abdominal and hip circumference are also used to assess body composition and changes in body fat distribution, the reductions in abdominal-visceral fat mass achieved here can also be calculated based on comparative MRI data in overweight people [25]. With an average reduction in abdominal circumference of 6.1 cm in the GU group, 9.1 cm in the D group and 8.3 cm in the (D+S) group, an average reduction in abdominal fat mass of 1.8 kg, 2.7 kg and 2.5 kg respectively can be assumed. Regardless of the respective intervention approach, this means a considerable improvement in metabolic fitness. In addition, the risk of coronary heart disease and type 2 diabetes is reduced. This also applies if the patient is still overweight in the BMI range of 27.7 to 29.9 kg/m2 after the intervention. Compared to subcutaneous fat, abdominal-visceral fat is easier to mobilize and accessible for lipolysis even in the presence of pre-existing insulin resistance [23, 25]. It is therefore all the more interesting that in the groups with diet-supported intervention, a statistically confirmed increased reduction in hip fat can be observed in the group comparison. Whether this can be assessed as a specific effect of the dietary supplement used remains to be discussed [1].

With the improvement in body composition and the reduction in body fat mass, a change in metabolic status and a regression in the systemically detectable factors of metabolic syndrome can be expected in the people studied here [10]. This is confirmed on the one hand by the significant reduction in serum leptin levels and on the other hand by the variables of carbohydrate metabolism (fasting glucose, plasma insulin). Interestingly, a greater drop in leptin levels was observed for the D group than would be expected for the corresponding reduction in fat mass. In addition, the blood glucose and plasma insulin levels in the groups with previously moderately elevated baseline values decrease significantly after the intervention is completed, so that the (x+s) values can be measured in the clinical-chemical normal range for all groups. This shows that, in particular, those people who show signs of metabolic syndrome in addition to being overweight benefit from the intervention, even with only average weight reduction [3].

The change in body composition associated with obesity and the unfavorable relationship between the body compartments fat mass and muscle mass have significant disadvantages for the Functional capacity of the biological Systems. In addition, they are changing the physiological equilibrium of pro- and anti-atherogenic as well as pro-inflammatory and anti-inflammatory factors [22, 26, 30]. This process involves muscle mass and physical growth. activity regulating energy turnover via metabolic anabolic and anti-catabolic factors [3, 5]. Disorders in the bioenergetic system as well as age- and inactivity-related sarcopenia intensify on the other hand, and can be used as a etiological basis for a variety of chronic degenerative diseases. Sensible Intervention Programs for Reduction obesity should therefore be Demonstrably beneficial changes in the ratio of fat mass and muscle mass and thus minimize atherogenic as well as inflammatory risk factors. This is demonstrably true for the intervention approaches shown here, such as health education, diet and exercise. Both atherogenic factors such as LDL cholesterol and inflammatory factors such as CRP and IL-6 are used in the case of unfavorable input group averages. In particular, in the diet group, the atherogenic LDL cholesterol content and its inflammatory concomitant reaction. As already mentioned above, for the symptom of insulin resistance and metabolic fitness, is also affected by this effect. it can be assumed that the The group of overweight people who already have elevated baseline levels of atherogenic and inflammatory risk factors before the intervention are particularly beneficial [30].

Significant, positive changes in cardiovascular fitness in terms of prevention can be achieved within the framework of the intervention carried out, and the weight improvement that has taken place as expected, in the sense of a functional adaptation [4]. On the other hand, improvements in the maximum, absolute Wattage only for the D group significant. Restrictive it should be noted that neither health education nor the Lifestyle instruction or the sports programme was aimed at improving maximum performance. For all participants, the focus was on increasing leisure activity and associated energy turnover through physical exertion. In a positive sense for the participants, should be taken into account that good fitness or genetically determined high aerobic performance (VO2max) is not automatically correlated with increased energy expenditure. Decisive for energy turnover is not aerobic capacity per se, but the regular use of the aerobic energy supply during the period of physical exertion [15, 28].

Furthermore, the results of the two diet-supported groups despite the offer a guided training program not for the (D+S) Group. Oriented on the energy balance, a targeted Weight reduction equivalent to both through the saving of food calories as well as through the activity-induced additional expenditure of calories [25]. For the (D+S) Group, the energy balance a mathematical advantage of approximately 1 000 kcal/week. This resulted in an increased weight reduction of approx. 2 kg in the Comparison of the investigation period to the D group. This benefit from the present However, results have not been confirmed. There in the (D+S) Group, however, not attention has been paid to a defined isocaloric diet compared to the DGgroup, this can be due to increased calorie intake and/ or lower use of the low-calorie supplements in the (D+S) Group be. On the other hand, to an additional, independently carried out leisure activity in the sense of the intended Lifestyle change for the D group. A Final Answer This question will only be possible after evaluation of the existing compliance protocols of all participants be. Acute weight loss As described, additional activity can only be achieved with quantitative control of the energy supplied and a demonstrably negative energy balance. [25]. This appears but not feasible in a practical intervention approach. Accordingly, dietary calorie reduction is usually preferred, and the increase in physical activity is more likely to be seen as an accompanying measure to retune and improve cardiocirculatory, metabolic and psych vegetative factors [11].

To combat obesity with increased physical activity, seems to be particularly promising in the long term, i.e. in prevention and after successful weight loss, less so in the short-term Intervention [19, 31]. If not calorically compensated by food, However, they also lead to small, additional daily sales with regular use, e.g. 2 km walking distance per day corresponding to an energy content of approx. 140 kcal [4] cumulatively a considerable amount of energy, here of 51 000 kcal per year corresponding to a fat mass of 5.7 kg or a fatty tissue equivalent of approx. 8 kg. This makes it easy to understand why a low positive fat and energy balance can lead to a significant disruption of weight regulation in the long term. Similarly, the statement of retrospective analyses in of the obesity intervention, that, in addition to the permanent calorie restriction, regular physical activity increases the long-term Therapy success [7, 11, 14, 16, 21].

The present results allow it to be said that with a pedagogically oriented health education significantly increases body weight and body fat mass in the range from approx. 0.25 kg/week to a period of 6 months. On the other hand, During this period, improvements in body weight and body fat mass in the range of approx. 0.4 kg/week on average can be achieved with diet-supported measures without undesirable side effects on the proportion of lean body mass. This success can be achieved through the offer of a supervised sports program in the design carried out here will not be measurably improved. In any case, weight reduction leads to an improvement in body composition and a Reduction of abdominal and visceral body fat mass. Accordingly, the weight reduction positive changes in the metabolic fitness as well as in proatherogenic and pro-inflammatory risk factors. Thereby seem to be defined at-risk persons as a subgroup of weight-loss measures with regard to benefit from a possible reduced risk of disease. In view of the fact that the available results as well as the assessment of the programme by the participants are positive, the form of the Intervention from a medical point of view sensible and recommended. One final evaluation of the presented intervention approaches and the therapy goals to be achieved in this way after the evaluation of the one-year data is foreseen.

Summary Weight loss is achievable - Half-Year Results of a Clinically Controlled, Randomized Intervention Study in Obese Adults

A. Berg, I. Frey, P. Deibert, U. Landmann, D. König, A. Schmidt-Trucksäß, G. Rücker, H. Kreiter, A. Berg, H.-H. Dickhuth, Freiburg

In a controlled, randomized trial, the effectiveness of various intervention approaches to reduce increased body weight was evaluated compared with each other. 30 people in each of three intervention groups (approach diet vs. diet + exercise vs. health education) were evaluated via a a total period of 12 months; for the dietary intervention, a Dietary supplement based on soy-yoghurt-honey (Almased®). The Half-year results on body composition (analysis of body fat percentage and lean body mass using BodPod® technology), physical performance as well as metabolic status and risk factor profile (blood glucose, plasma insulin, serum leptin; total, HDL, LDL cholesterol, triglycerides; plasma fibrinogen, serum hs-CRP, serum interleukin 6) show significant improvements in body composition and health status for all groups. Thus, weight loss is supported by positive Changes in metabolic fitness as well as in pro-atherogenic and pro-inflammatory risk factors were accompanied. In the diet-guided Significantly higher weight loss (on average of -8.9 kg) was achieved by groups than by teaching health and lifestyle content (on average of -6.2 kg). The sports offer, on the other hand, is not accompanied by additional success in weight loss. Among the offer of low-fat, but a high-protein diet can also help with weight reductions in the range of 0.5 kg/week no loss of muscle mass can be observed as an undesirable side effect. Intervention programmes with an energy deficit in order to Accordingly, 700 kcal/day appear under observation of the body composition also medically justifiable in the long term.

Ernährungs-Umschau 50 (2003), pp. 386–393