Introduction

The need to repeatedly emphasize the importance of obesity and its direct link to lifestyle arises from the fact that, despite all efforts, the proportion of overweight people in our population continues to increas despite all efforts [1, 2]. Obesity is more than just a cosmetic problem, as it is epidemiologically proven that overweight people are a risk group for atherosclerotic and metabolic diseases that require therapy [3, 4].

In turn, Germany is being overrun by a wave of weight reduction programs. Around 200 such programs are currently programs are currently offered by various institutions. Only a few programs offer reliable success, and only a few have been evaluated and meet the criteria of continuous quality management. Despite all this, there is no doubt that only a lasting change in dietary and activity behavior towards an energetically balanced lifestyle and a simultaneous improvement in dietary quality can lead to lasting success [5].

Against this background, the Department of Rehabilitative and Preventive Sports Medicine at the University Hospital of Freiburg has already in October 2003 [6] reported on the first successes of a controlled and randomized study on the reduction of increased body weight in adults. After the publication of the half-year results in the past, the one-year results should now show that the feasibility of weight and fat mass reduction according to the calorie balance approach is possible with reasonable effort for the participants, is not possible. The scientific and practical results obtained in this way should also serve as a basis for the creation of a standardized training program for the treatment of obesity and its associated risk factors [7].

Methodology

The individual parts of the methodology have already been described in detail in the previous publication [6].

Participant

After information sessions on the topic of obesity, the study participants were selected according to defined for inclusion and exclusion (age: 35-65 years; BMI: 27-35 kg/m2 ; 
Symptom-free exercise capacity >75 watts; stable weight behavior in the past 3 months; expressed interest in the intervention program with randomization; no medicated lipid metabolic-disorder) 
In the study, 202 potential participants were pre-screened (clinical status, stress ECG, laboratory status) and 30 participants were randomly assigned to one of the three intervention groups: Group 1: diet-induced weight loss (D group), Group 2: weight loss induced by diet and supervised exercise (D+S group), Group 3: health education induced weight loss (GU group).

7 participants dropped out in the first 24 weeks of the intervention; there were no further dropouts in the second half of the intervention, so that the scheduled one-year examination could be conducted for 83 participants at the end of 48 weeks. The personal and anthropometric data of the people included in the study are shown in Table 1; there were no differences for the respective participants in the intervention groups formed in this way. The project started and ended in December for all groups. All participants took part in the study voluntarily and with written informed consent; the participants did not receive a success or participation fee. The study was conducted with consent.

The study was conducted with the approval of the Ethics Committee of the Medical Faculty of the Freiburg University Hospital.

Intervention Program

All participants were informed in detail about the basic procedure, the contents and objectives of the intervention and the importance of weight reduction; a target reduction in the individual BMI value of 2.5 units was agreed with all participants as the target criterion for the planned intervention. This was to be achieved by changing the energy balance. The instruments used for this purpose are described in detail in the first publication [6]. The aim of the intervention in all groups was to teach and implement healthy eating and exercise habits on a self-responsible basis. In the "diet" and "diet and exercise" groups, a commercially available food supplement based on soy, yogurt and honey (Almased®) with a low-glycaemic index (GI = 27, tested according to WHO/FAO 1998 [Berg A., personal communication 2004]) and low glycemic load (GL = 3.2 in relation to a standard portion of 40 g). This use was justified on the one hand, with the protection against a possible protein deficit and for the preservation of the muscle mass with calorie restriction, and on the other hand however also as motivation assistance and introduction to the change in diet. 

The amount of food supplement consumed over the period of the overall intervention is documented in Figure 1 depending on the respective intervention phases. The review of compliance for the respective consumption quantities showed that 80% of the body weight-related daily recommendation was achieved in the first twelve weeks. The "diet and exercise" group additionally received an duration-oriented, guided exercise program of 2 x 60 minutes per week with the aim of achieving a weekly energy turnover of approx. 2,500 kcal/week, corresponding to 30 METh/week, as a leisure activity in the 7th-24th week. In the second half of the intervention, the participants were required to maintain the learned or recommended activity status on their own initiative.

Anthropometric-performance-physiological status and behavior

Metabolic status and risk factor profile

Statistical analyses

Results

Adherence and acceptance of the program

Following the previously published six-month results [6], there were no further dropouts; of the 90 people included in the study, 83 participants could be conclusively examined. 83 % of participants were very satisfied or satisfied with the program; all participants stated that they would recommend the program to others. 80 % of the participants in the diet-supported groups described the nutritional supplement used as a therapy aid that was noticeable to them. In the first six weeks of the intervention, the diet suppurted groups consumed an average of 516 g of the recommended food supplement was consumed per participant per week in the diet-supported groups, and 250 g of the food supplement was consumed in the 7th to 12th week (Fig. 1).

Activity behavior

Over the course of the year, a significant change in activity behavior was achieved by the behavior-oriented program in groups (p<0.05). In the activity logs collected at the same time of year (beginning of December), an mean increase in leisure-time activity of 5.7 METh/week was secured. In practice, this corresponds roughly to one hour of physical load in the 125-watt intensity range and a regular increase in energy consumption of approx. 430 kcal/week. According to the learned behavior in the group-specific program, this increased activity in the (D+S) group was mainly due to sports activities, in the other groups it was due to increased everyday activities.

Cardiovascular Fitness

Over the course of the year, the ergometrically tested maximum physical performance remained unchanged. Body weight-related physical performance increased significantly (p <0.05) in all groups by an average of 10% (GU: +7.5%; D: +9.8%; D+S: +11.2%). All groups also showed a favorable change in circulatory and exercise regulation with the weight loss achieved. The heart rate at rest decreased by an average of 7 beats/min (p <0.01) and under stress (75 watt level) by 5 beats/min (p <0.05). Systolic blood pressure only improved in the diet-supported groups by an average of 10 mmHg (p <0.01) at rest and during exercise; for the sports-supported (D+S) group, diastolic blood pressure also decreased by an average of 8 mmHg at rest and under exercise (p <0.001) and lactate levels decreased by 0.36 mmol/l (p <0.001) under exercise (75-watt level).

Weight loss and anthropometric variables

A significant (p < 0.001) reduction in body weight and BMI was shown for all treatment groups after the 48-week overall intervention (Table 2). As in the six-month study, the diet-supported groups performed better in the group comparison by approx. 2 kg weight difference and 0.5 BMI units. The agreement reached with the participants at the start of the intervention (weight reduction of 2.5 BMI units) was only achieved in the GU group only in exceptional cases. Assessed on the basis of the guidelines of the German Obesity Society (DAG) [12], 40% of the participants in the GU group, 60% in the D group and 62% in the (D+S) group achieved the goal of a weight reduction of at least 5% of the initial weight at the 1-year examination according to intention-to-treat criteria. For all groups, more than 80 % of the observed weight reduction can be explained by the decrease in fat mass. The reduction in lean body mass was not significant in all groups and accounted for less than 20% of the weight reduction. As in the six-month study, there was a significantly greater reduction in hip circumference was found in the group comparison for the diet-supported groups (p = 0.038).

Metabolic regulation

In all groups, there was a significant reduction in serum leptin levels (Table 3) and fasting glucose levels after the overall intervention. With initially elevated values, the (D+S) group also experienced a significant decrease in plasma insulin. In contrast to the baseline examination, the (x+s) values in fasting blood glucose and plasma insulin were within the clinical-chemical normal range for all groups at the end of the year.

Risk Factor profile

After the intervention phase, there was a highly significant reduction in total and LDL cholesterol in all groups (Table 3). LDL cholesterol levels were on average 14% lower than at baseline. Impressive was the significant increase in HDL cholesterol in the range of 12 % or 4-9 mg/dl on average. In contrast to the atherogenic lipid profile, the changes in the inflammatory profile were not uniform and were only significantly improved only in one case. In the group comparison, however, no significant differences within the individual groups.

Discussion

Against the background of the demand to develop feasible and practical intervention models for the successful treatment of overweight in adults [12, 13], the annual results presented here show that the effective reduction of an increased body weight, defined as a weight reduction of at least 5% of the initial weight, is possible for the majority of participants (up to 62% depending on group allocation) after 12 months. Moreover, this result can be achieved via the desired reduction in body fat mass without detriment to fat-free mass [14]. The set goal of demonstrating the feasibility of weight and fat mass reduction as a success of a therapeutic lifestyle intervention based on the principle of reduced caloric balance [9] was thus achieved. The scientific and practical experience gained in this study in the care and therapy of overweight adults has already been implemented in a standardized training concept, which has been offered nationwide since the beginning of 2005 under the name M.O.B.I.L.I.S. and the costs of which can also be reimbursed as a supplementary therapeutic service in accordance with § 43.2 SGBV [7].

Summary

Weight reduction through lifestyle intervention
One-year results of a clinically controlled, randomized study with overweight adults

Aloys Berg, Ingrid Frey, Ulrike Landmann, Peter Deibert, Daniel König, Andreas Berg, Hans-Hermann Dickhuth, Freiburg

Against the background of developing and evaluating practical intervention models for the successful treatment of overweight in adults, the annual results of a clinically controlled intervention study at the University Hospital of Freiburg, which have already been published, show that the effective reduction of increased body weight is possible for the majority of participants (up to 62% depending on group allocation) even after 12 months. The weight loss achieved can be achieved via the desired reduction in body fat mass without any disadvantages for fat-free mass. Thus, on the one hand, the feasibility of weight and fat mass reduction as a success of a therapeutic lifestyle intervention based on the principle of reduced calorie balance was demonstarted and, on the other hand, the favorable influence of weight reduction on concomitant atherogenic risk factors was once again proven. Thus, reductions in LDL cholesterol of 14% on average and increases in HDL cholesterol of 12% on average were observed over the course of the year. The theoretical and practical experience gained in this study in the care and therapy of overweight adults has already been implemented in a standardized training concept, which has been offered nationwide under the name M.O.B.I.L.I.S. since the beginning of 2005.

Ernährungs-Umschau 52 (2005), pp. 310-314