Obesity is the systemic disease, induced by disturbances of energetic metabolism homeostasis and resulting in the increase of fatty body mass above customary standards. Major disorders connected to obesity are: the increase of insulin, glycocorticoids and leptin concentrations, the decrease of growth hormone secretion in the peripheral blood as well as higher rate of its metabolism in tissues. The body mass reduction and maintenance of the proper body mass for a longer time are essential factors diminishing risk of health complications during the later period of life. On the basis of the above statements, the following questions were put in the present study:
How the reductive diet and systematic physical exercise (of anaerobic type), together with the dietary education, influence on the body mass reduction and lipid parameters in the blood?
Are there differences between concentrations of selected neurohormones, with relation to the character of the therapy and the degree of overweight and obesity?
How the applied reductive diet, physical exercise influence and nutritional education influence on the level of hormones contributing to carbohydrate-lipid metabolism and to the regulation of body mass in boys and girls?
To what degree the dietary education may contribute to changes of dietary habits and to lifestyle improvement of youths with overweight and obesity?
Youths were qualified to participate in the study by a doctor, after exclusion of hormonal disorders, when the simple obesity was diagnosed as the reason of excessive body mass. The degree of overweight and obesity was determined in each case from values of the body mass index (BMI).
Investigations were conducted with the consent of subjects and their parents as well as in agreement with Local Committee of Ethics in Scientific Research of the Karol Marcinkowski University School of Medical Sciences in Poznań.
The study was performed on two following groups of youths:
1) Investigations on subjects qualified to the group I were made in 1999-2002, during 28-days rehabilitation turns. The group consisted of 48 boys (13 with overweight and 35 with obesity), at the mean age of 15.6 ± 1.40 years, and 52 girls (25 with overweight and 27 with obesity), at the mean age of 16.1 ± 1.21 years.
During the rehabilitation period, low-calorie diet at the level of 1300 kcal, with the average 30g cellulose content, was applied together with the increased physical activity.
Three days a week, subjects performed 30-minutes exercise on a cycloergometer, each at an individually matched load, adequate to 70% of 
, at frequency of pedaling 60 per minute. In addition, subjects performed 2-hours walks and 1-hour sport activities (game sports, swimming). Physiological-biochemical tests were made twice, on the second and on the third day after arrival (I term) and on the 26th and 27th day of the rehabilitation period (II term). On the second day, anthropometrical indices were measured (BMI, WHR, height, body mass), and the body contents were determined (fatty mass – FM, fatty-free mass – FFM, total body water – TBW). The body content was determined with the electrical bioimpedance method (Body Impedance Analyser – Akern, BIA-101, Florence, Italy), on the basis of the skin resistance to direct current flow. Results were calculated as the absolute values of mass (kg) and as percentage of the total mass. The maximal oxygen absorption (
) was measured with an indirect method, using the Ästrand-Rhyming normogram [Ästrand, Rhyming 1954]. The normogram of interrelations between the load applied to the cycloergometer and the heart rate, at which subjects achieved functional balance, was used for this purpose. This normogram made possible counting the oxygen consumption in liters per minute.
On the next day (the third day of the rehabilitation turn), two hours after a standard breakfast (consisting of bread with butter and tea without sugar), subjects performed 15-minutes exercise test on the cycloergometer, at intensity adequate to 70% of 
. The blood for analysis was taken in a fasting state, at rest, from the finger pulp and from the basilic vein. The capillary blood was drawn 3 minutes, and the venous blood 5 minutes after completion of the exercise test. In the capillary blood the following parameters were determined:
acid-base balance parameters, with the use of AVL-995 Hb analyzer, produced by Graz Austria (Automatic Blood Gas System),
the lactic acid concentration, with the enzymatic method with the test by Boehringer Mannheim.
In the serum of venous blood, the following lipid-glucose parameters were determined with tests by Cormay:
total cholesterol,
HDL-cholesterol fraction,
triacyloglycerol concentration (TG),
glucose concentration,
and the selected hormones were determined with radioimmunological methods:
insulin, growth hormone and cortisol concentrations, with the use of special sets produced by the Research and Development Radioisotope Centre in Świerk, Poland,
C-peptide concentration, using the Biodata Serono set, Italy,
leptin concentration, using the Linco Research set, USA.
The LDL-cholesterol was calculated from the Friedewald’s formula. Moreover, the cholesterol index of atherogenesis was calculated from the Krawczuk-Rybakowa formula [Krawczuk- -Rybakowa et al., 1997].
During the rehabilitation turn, the lectures on the role and significance of food, nutrition and dietary habits in health promotion and obesity prevention were given.
2) Investigations on subjects qualified to the group II were conducted in 2002, in Poznań and Leszno. Youths belonging to this group did not participate in the rehabilitation turn. They were treated with dietary régime and nutritional education in the form of lectures. This group consisted of 58 persons, 37 girls at the mean age of 15.6 ± 1.4 years and 21 boys at the mean age of 15.5 ± 0.95 years. Among girls, 18 had overweight and 19 were diagnosed as obese. Among boys, overweight was established in 10, while obesity in 11 subjects. All the youths from this group were proposed in the program of body mass reduction to apply diet that delivered daily about 1600 kcal. 20 hours of lectures and consultations were carried out in order to transfer the knowledge about nutritive components of food, ways of proper nutrition, the role of dietary habits in health promotion and obesity prevention, as well as the role of motor activity in health improvement. At the beginning and at the end of the research period (that lasted for 6 months) anthropometrical and biochemical measurements, and the exercise tests were performed in all subjects – in the same way as for the group I.
The analysis of the obtained results led to the following conclusions:
The complex therapy contributed to the more pronounced decrease of the body mass, in comparison to the simple dietary therapy. This points to the significance of the physical activity in the reduction of body mass.
Higher therapeutic effects of low-energy diet associated with physical activity was expressed as greater changes of mean values of the waist/hip index, used as the criterion of the obesity type.
In parallel to the decrease of the WHR index in the group of boys under the complex therapy, improvement of lipid metabolism parameters was observed. One should appreciate this as the factor diminishing risk of atheromatosis in the future.
In the group of girls, mean parameters of lipid metabolism in the blood were lower in comparison to the male group of the same age. Mean values of these parameters were higher in obese than over weighted girls in both groups investigated.
In obese youths of both sexes, mean values of the parameters investigated were higher than in the groups with overweight.
Cholesterol index of atherogenesis was higher in youths with larger body mass, and its more pronounced decrease was determined in groups that underwent the complex body mass reduction therapy.
The effects of the body mass reduction, both in over weighted and obese subjects, were: the decrease of concentrations of leptin, C-peptide and cortisol, as well as the increase of GH concentration. No significant differences of hormone concentrations were noticed between groups under various types of therapy.
Besides the higher body mass reduction, the complex therapy induced the increase of the physical capacity and exercise tolerance.