Weight reduction is attainable

Six months results of a clinically controlled, randomized intervention study with overweight adults

Aloys Berg, Ingrid Frey, Peter Deibert, Ulrike Landmann, Daniel König, Arno Schmidt-Trucksäß, Gerta Rücker, Helga Kreiter, Andreas Berg and Hans-Hermann Dickhuth, University of Freiburg, Dept. Rehabilitation, Prevention and Sports Medicine, Center for Internal Medicine, Germany

Methods

Proband
202 potential participants were screened out of 522 interested, overweight candidates. The screening process took criteria for inclusion and exclusion of participants according to the test plan into consideration (clinical examination, stress-EKG, lab status).

Afterwards 30 participants each were randomly assigned into three intervention groups. (illustration 1):

• Group 1: diet induced weight reduction (D-Group)
• Group 2: diet and exercise induced weight reduction (D+E-Group)
• Group 3: health education induced weight reduction (HE-Group)

Four of the assigned participants were already excused at the start of the study because they were not satisfied with their group assignment. Three more participants quit the study for personal reasons. The personal and anthropometric data of the participants are shown in illustration 1. In the comparison of the statistical data of personal characteristics no differences for the individual probands of the intervention groups were noted. At the conclusion, after 24 weeks, the semi-annual study could be carried out with 83 participants. Each participant took part in the study on their own free will and furnished a written consent notice. They did not receive any compensation or financial gratuity (success- or participation fee). The study was carried out in the presence of the "Unbedenklichkeitsvotum" (with permission) of the ethics committee of the medical faculty of the University clinic of Freiburg.

Health Instruction, Diet and Sport Program
Each participant was thoroughly informed of the basic progress, the contents and goals of the intervention, as well as the importance of weight reduction. As ultimate criteria, a reduction of individual BMI values of 2.5 units was agreed upon. This was supposed to be reached with the specifically modified daily energy balance.

In addition all participants were informed about a healthy and active life style and were advised to reduce the fat percentage of the meals they chose on their own. The contact of reference was the physician working with the study. Five clinical visits, three group sessions and 2 individual sessions of 20 minutes each were done in six-week time intervals.

The participants of the group "Diet" had to reduce their BMI values with a calorie-reduced diet. According to an individual, body weight specific scheme, two of three scheduled meals during the first six weeks, were replaced with a protein-rich dietary supplement based on soy-yogurt-honey (Almased; 100g contain 54,1 g protein, with 45,0 g soy protein and 8.3 g milk protein, 31,5 carbohydrates and 0,6 g fat with a burn factor of 96 kcal. Just like in the "health education group" the participants of the "diet group" had to do five clinical visits in intervals of six weeks over a time period of 24 weeks. The participants of the group "diet and exercise" were instructed to take part in a regular, endurance oriented and guided sports program of 2 x 60 minutes per week. After an introductory period of six weeks, the goal was to reach a weekly energy consumption of approximately 2,500 kcal/week, equivalent to 30 METh/week, in the second part of the intervention (7th - 24th week). The participants of the group "diet and exercise" were also informed about a "healthy" and active life style and were encouraged to reduce the fat percentage of the meals they chose on their own. The reference contacts were a PE instructor and the physician working with the study. This group also had 5 clinical visits within the time frame of 24 weeks in six-week intervals, in addition to their weekly sports session.

Anthropometric and performance physiological status
In the beginning of the study and after the 24-week intervention, the body composition and physical performance level of the participants was examined. In conclusion of the volume of the entire body, in analogy for hydrostatic body density measurement, the fat percentage of the body was determined with the BodPod technology (17) and the fat mass of the body as well as the fat-free body mass were calculated.
The BodPod technology enables the exact determination of the body volume in an enclosed system with pressure sensors via the percentage of the individually expressed air volume. In addition the indirect evaluation of the abdominal and visceral, as well as subcutaneous fat distribution of stomach and hip circumference was measured in each participant (25). The physical performance level in each participant at the beginning and after the intervention phase were documented in a defined performance protocol with standardized bicycle ergometry (4) (half seated, three-minute rating levels at 25 watts, starting with 50 watts). The activity and nutritional conduct of the individual participants was documented via protocol. Satisfaction and acceptance of the program were evaluated via questionnaire.

Metabolic status and risk factor profile
The laboratory parameters for the determination of metabolism regulation (blood glucose, plasma insulin, serum leptin), as well as for the atherogenic (complete cholesterol, HDL, LDL, triglyceride) and inflammatory risks (plasma fibrinogen serum-hs-CRP, serum- interleukin 6), were determined in all participants in the beginning and after the intervention phase in a fasting and resting state (in the morning between 8:00 and 9:00 AM, following 12 hours nutritional abstinence, as cubital venous blood sample) via standardized and previously described clinical and chemical analytical procedures (10).

Statistical Evaluation
The statistical evaluation was created via SPSS 11.0.1. For the inter-individual comparisons between the status before the intervention and the status after 24 weeks within the groups, the Wilcoxon test for associated samples was used.
To test the hypothesis whether die differences (before and after the intervention) between the groups were distinct, a variance analysis was conducted. Variables that weren't distributed regularly (CRP, Insulin, IL-6) were standardized in a logarithmic transformation.

Results

Adherence and acceptance of the program
Of the 90 study participants 83 were successful with their assigned programs and the connected half-year examination over the course of 24 weeks. The majority of the participants (83%) were satisfied to very satisfied with the program. All participants (100%) stated that they would recommend the program, i.e. the therapy basics and use them over again. In both diet-supported groups 80% of the participants considered the nutrition supplement a noticeable therapy aid. 15% were only partially convinced of the diet supplement, 5% not at all. The exercise-supported diet group considered the exercise program the most important therapy part.

Weight loss and anthropometic variables
Each therapy group showed a significant reduction in body weight and BMI values (table 2a) after the 24 week intervention. When comparing groups, the diet-supported groups had much better results (table 2b). The therapy goal that was agreed upon at the beginning of the intervention was met in the HE group by 12 of 28 participants (43%), in the diet group by 20 of 28 participants (71%) and in the D + E group by 16 of 27 participants (59%). Evaluated according to the principles of the German Adipositas Society (DAG (12), 71% of the health education group participants, 89% of the diet group participants and 93% of the diet and exercise group participants reached the goal of a 5% weight reduction.
In all groups, the weight reduction could be attributed to a simultaneous decline in fat mass (table 2b). In the correlation analysis a significant biological dependency between weight reduction (x) and corresponding reduction of fat mass (y) is shown. (r2 HE group = .85, r2 D group = .74, r2 D + E group = .75) The diet-supported group experienced more decrease in fat percentage and total fat mass with higher weight reduction. (table 2b) It is interesting to note that in the group comparison a significant reduction in hip circumference was visible.

Heart-circulation-fitness
With the intervention, the ergometrically tested, maximum physical performance was only significantly improved in the diet-group (p=0.023) - a five percent increase from 155 watts to 163 watts. In the group comparison this does not show as a significant change. All groups showed positive changes, as expected, in frequency regulation, blood pressure regulation and lactate regulation, once they reached the desired weight reduction. The heart frequency, in calm and stressed status, slowed 8-10 beats/minute (p = <0.001), the systolic blood pressure was lowered with an average of 10 mmHg (p = <0,01) and for the H + E Group the lactate value under stress (75 watt level) was reduced by 0,24 mmol/l (p = <<0,01).

Metabolic regulation
All groups showed a highly significant lowering of their serum leptin level after the intervention phase (table 3a); in respect to the individual median weight reduction as Aleptin/AKG, the leptin reduction with 1.7 mg/ml/kg was especially strong in the D-group. (table 3b). At the conclusion of the interventions a significant lowering in the fasting level of the blood glucose and the plasma insulin was noted. (table 3a,b) A decisive factor for the reduction, however, was the individual initial value at the beginning of the study. In each group the (x+s)-values for fasting glucose and plasma insulin were at an impressive clinical-chemical normal range after the intervention.

Risk factor profile
In all groups we found a significant lowering of the total cholesterol and LDL cholesterol (table 3a) after the intervention phase; however with the low fat and weight reducing intervention a lowering of the HDL cholesterol in a range of 5-7 mg/dl was also observed. Parallel to the atherogenic lipid profile, changes were also noted in the pro-inflammatory profile. In relation to the previously slightly elevated initial values, the diet-supported groups showed significant improvements in the values for hs-CRP and IL-6. In the group comparison the changes caused by the intervention were not significantly different in the individual groups.

Discussion
The introduced, controlled and randomized study was conducted to develop a successful treatment for overweight adults with the background of a feasible and close-to-real-life intervention model. The results show that this is effectively possible with different onsets, for instance with the principle of a calculated calorie balance through reduction of body fat mass. In addition, scientific and practical experiences in the therapy of overweight adults and in the therapy of adiposity and its associated risk factors were gathered.

In the sense of an agreed upon therapy goal (lowering of BMI value by 2.5 units), satisfying successes were achieved with a change in nutrition, personal conduct and physical activity {6,8,18,21,25,27]. The findings in the body composition for all three groups show that the fat percentage in the body mass can be reduced within a range of expectable effort, without infringing upon the fat free mass. If - as shown in the diet-supported group - calories and protein intake is restricted to values of less than 1000 kcal per day, with the offer of a low-fat and protein-rich diet, a loss of weight in a range of 0,5 kg/week can be attained without physiological negative imbalance of nitrogen and the often observed, unwanted loss of muscle mass. Intervention programs with an energy deficit of approximately 700 kcal/day seem to be possible in a long-term medical way, with observation of body composition. By adding a protein source, beneficial to the nitrogen balance [20,29], it seems that under the examined conditions, the maintenance of fat free body mass and the muscle mass, important for the base- and energy consumption, is possible even without additional directed or supervised physical activity.

If, in addition to body mass, the results of stomach and hip circumference are used to judge body composition and the alteration of body fat distribution, the attained reduction in abdominal-visceral fat mass can be calculated in reference to comparable MRT data in overweight subjects [25]. With a median reduction of 6.1 cm stomach circumference in the HE-group, 9,1 cm in the D-group and 8,3 cm in the D + E -group, the assumption of a median stomach fat reduction of 1,8 kg, or 2,7 kg and 2,5 kg can be made.
Regardless of the individual intervention onset, this shows a significant improvement of the metabolic fitness. In addition the risk for coronary heart disease and type 2 diabetes is lowered. This is even true with continued overweight after the intervention in a BMI level of 27,7 to 29,9 kg/m2. Compared to the subcutaneous fat, with already existing insulin resistance, the abdominal-visceral fat is better mobilized and easier accessible for the lipolysis [23,25]. This makes it even more interesting that in the group with diet-supported intervention, compared to the other groups, statistically a much higher reduction of hip fat was observed. Whether this is to be viewed as a specific effect of the dietary supplement remains to be discussed.

With the improvement of body composition and the reduction of body fat mass, a change in metabolism status and regression in system proven factors of the metabolic syndrome in the examined persons is to be expected [10]. This is confirmed with a significant reduction of the serum leptin level for one and the variables of the carbohydrate metabolism (fasting glucose, plasma insulin). Interestingly, the D-Group showed a stronger reduction in the leptin level than was to be expected for the corresponding reduction of fat mass. In addition, after the completed intervention the groups with previously moderately elevated initial values, blood glucose and plasma insulin levels sank significantly, so that in all groups the (x + s) values were measured in a clinical-chemical normal range. This shows that especially those persons, who in addition to overweight showed signs of the metabolic syndrome, profited from the performed intervention even if they only reached average weight reduction.
The changes in body composition caused by overweight, and the unfavorable developing relation between body compartments fat mass and muscle mass, show significant disadvantages for the functional capacity of the biological systems.

In addition they change the physiological balance between pro- and anti-atherogenic, as well as inflammation-furthering and inflammation-hindering factors [22,26,30]. Muscle mass and energy consumption, regulated through physical activity, intervene in this process with metabolism anabole and anti-catabole factors [3,5]. Disorders in the bio-energetic system, as well as in the age and inactivity related sarkopeny are strengthened alternately and can be seen as the aetiological basis for a multitude of chronic degenerative illnesses. Sensible intervention programs for the reduction of overweight should therefore alter the relation of fat mass and muscle mass in a proven positive way and minimize atherogenic as well as inflammatory risk factors. For the noted intervention onsets of health education, diet and exercise, this obviously is the case. Atherogenic factors like the LDL cholesterol, as well as inflammatory factors like CRP and IL-6 were significantly influenced in initially unfavorable group median values. Especially in the diet group the atherogenic LDL cholesterol percentage and its inflammatory side effects were altered positively. As already mentioned for the symptom of insulin resistance and metabolic fitness, this effect is also assumed to have the greatest benefit to the group of overweight persons, who showed the highest initial values of atherogenic and inflammatory risk factors before the intervention [30].

Significant, in the sense of prevention, positive changes in the heart circulatory fitness, can be documented in the realm of the performed intervention and the attained weight improvement due to functional adaption. However, improvements of the maximum, ultimate performance ability in watts, were only significant in the D-group. In a qualifying sense it has to be mentioned that neither the health education nor the instructions for life style, or the exercise program were geared towards improvement of maximum performance capacity. Foremost the focus for all participants was an increase of leisure activity and the directly related energy consumption of the physical activity. In a positive sense for the participants it has to be considered that good fitness or genetically determined high aerobic performance ability (VO2max) is not automatically correlated with elevated energy expenditure.

A deciding factor for energy expenditure is not the aerobic capacity per se, but the regular use of the aerobic energy provision during the time frame of physical activity [15, 28].

No further differences are noted in the results of both diet-supported groups, regardless of the opportunity of a guided training program for the (D + S) group. Looking at the energy balance, a goal oriented weight reduction equivalent to limitation of nutritional calories as well as activity induced, elevated expenditure of calories, is attainable [25]. The (D + S) group showed a calculable advantage in the energy balance of approximately 1000 kcal/week. This assumes a higher weight reduction of approximately 2-kg for the examination time frame in comparison to the D-group. This advantage, however, is not confirmed with the results on hand. Since the (D + S) group was not focused on a defined, iso-caloric nutrition, like the D-group, this can be attributed to a higher calorie intake and/or a lesser use of the calorie reduced nutritional supplement in the (D + S) group. In addition, it could be the additional, independently chosen leisure activity in the sense of the aspired life style change for the D-group. A conclusive answer of this question will only be

possible after the evaluation of the compliance protocols of all participants. An acute weight reduction by adding more activity can be attained only, as mentioned, with quantitative control of energy intake and a proven negative energy balance [25]. This does not seem possible in a true-to-life intervention onset. Corresponding to this, dietetic calorie reduction is usually preferred, and an increase in physical activity is more of a support measure for the adaptation and to improve the cardio-circulatory, metabolic and psycho-vegetative factors [11].

To battle overweight with increased physical activity, seems promising on a long-term basis, i.e. in the prevention and after successful weight reduction, not so much in the short-term intervention [19,31]. Even if not compensated with lower calorie nutrition, already little, additional daily expenditure on a regular basis, i.e. 2 km walking per day correspond to an energy expenditure of approximately 140 kcal [4], which accumulates to a notable energy amount of 51000 kcal per year, which is equivalent to a fat mass of 5,7 kg or a fat tissue of 8 kg. This makes it clear why even a limited positive fat and energy balance can lead to significant disorders in weight regulation in the long run. In addition, the statement of retrospective analysis in the adiposity intervention is confirmed, that parallel to permanent caloric limitation, regular increased physical activity can influence the long-term therapy success [7,11,14,16,21].

The presented results allow the statement that body weight can be significantly lowered with a pedagogically oriented health education, and the body fat mass can be lowered in a range of 0,25 kg/week over a time frame of 6 months. With diet supporting measures, improvements in body weight and in the body fat mass in a range of 0,4 kg/week on average, are attainable in the same time frame without undesirable side effects in the percentage of fat-free body mass. This success cannot be improved with a supporting exercise program in the performed design. In any case, weight reduction leads to an improvement in body composition and to a reduction of abdominal and visceral body fat mass. Accordingly the weight reduction is accompanied by a positive change in metabolic fitness and in pro-atherogenic and pro-inflammatory risk factors. With this it seems that defined persons at risk, as a sub-group, benefit especially from the weight reducing measures in regards to a reduced illness risk. With the background that the documented results, as well as the assessment of the program by the participants are perceived positively, the here introduced from of intervention seem sensible and recommendable from a medical stand point. A conclusive evaluation of the introduced intervention onsets and the desired therapy goals, after the evaluation of the one-year data, is planned

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Correspondence address:
Prof. Dr. med. Aloys Berg
Universitätsklinikum Freiburg-
Zentrum für Innere Medizin
Abt. Für Rehabilitative and Präventive
Sportmedizin
Hugstetter Str. 55
79183 Freiburg
E-Mail: berg@msnl.ukl.uni-freiburg.de

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