**3.1 Personalization of health-promoting fitness programs for young women based on PPARG gene polymorphism**

To personalize health-promoting fitness programs for young women, a study was conducted that included an assessment of women's physical fitness before and after the implementation of two 4-month health-promoting fitness programs (aerobic and resistance workouts). The personalized approach presupposed genotyping women according to Pro/Ala polymorphism of the PPARG gene. At the beginning of the pedagogical experiment, we formed two groups of women, the experimental group 1 (EG1) (resistance training, n = 24) and the experimental group 2 (EG2) (aerobic training, n = 20).

The results of the study showed the dependence of young women's physical fitness on their genotype for the above-mentioned polymorphism as a result of undergoing fitness programs by them. Resistance workouts caused significant changes in body composition, with a slight decrease in body weight and girth for women with Pro/Ala and Ala/Ala genotypes, while among women with Pro/Pro genotype, there was a significant decrease in body weight and girth. The level of physical fitness in women with Pro/Pro genotype increased by 11.1%, and in women with Pro/Ala and Ala/Ala genotype by 10.5% (p < 0.05) under the influence of the strength fitness program.

The patterns of the changes in the parameters of physical condition differed between the women with Pro/Pro genotype and Pro/Ala and Ala/Ala genotypes, who participated in aerobic training. Aerobic training resulted in significant changes in the bodyweight of young women in both subgroups.

Identification of genetic markers allows applying a differentiated approach in the development of fitness programs, which stipulates choosing the structure of the program, the ratio of aerobic and resistance activities, exercise intensity, and pulse regimes depending on the polymorphism of the *PPARG* gene [52].

### **3.2 Microbiome and obesity**

The global obesity epidemic has stimulated a great interest in studying the effects of microbial metabolome on the metabolic profile and maintenance of the energy homeostasis of an individual. The study by Turnbaugh et al. was one of the first that showed the relationship between the gut microbiota and increased body weight [53]. These and other similar findings formed a basis for the development of ideas about the mechanisms of microbiome influence on metabolic pathways.

The introduction of new technologies based on the achievements of genomics, transcriptomics, proteomics, metabolomics, and bioinformatics, in the last decade, has revolutionized and expanded the understanding of the structure and function of the human microbiome, as well as of its key role in regulating metabolic processes in the macroorganism, absorption of nutrients, endogenous synthesis of essential enzymes, vitamins, and biologically active compounds [54].

### **3.3 Functional significance of microbial enterotypes**

The microbiome consists of about 100 trillion microorganisms that exist in a symbiotic relationship with human hosts [55] and can be classified into four enterotypes: Bacteroides, Prevotella, Ruminococcus, and Firmicutes, which have different dominant classifications, pathways, functions, and correlations between coexisting genera. The Bacteroides enterotype metabolizes carbohydrates and proteins with enzymes involved in glycolysis and pentose phosphate pathways. Prevotella and Ruminococcus contribute to the transport and absorption of monosaccharides by enriching the membrane and binding gut mucin to hydrolyze it. Enterotypes use different strategies to obtain energy from substrates present in the gut ecosystem. The specific composition of enterotypes responds to special mechanisms of metabolism of carbohydrates, amino acids, and fatty acids, which determine the frequency of obesity and obesityrelated metabolic diseases [56].

16S rRNA microbiome sequencing identified the relationship between microbial diversity and different physiopathological conditions and allowed to observe the behavior of different types and genera of bacteria in combination with different phenotypes, different types of diets, and, in particular, obesity [57]. It is assumed that the microbiome can regulate the extraction of energy substrates from food and energy balance of the body, thus promoting the development of obesity or protecting against it. This hypothesis was confirmed in a study by Gordon, which reported an increase in fat content in the body of gnotobiotic (germfree) rats after fecal transplantation from obese rats [58]. Some studies have shown an increase in the percentage of Firmicutes and a decrease in the percentage of Bacteroidetes in obese humans compared to humans and underweight rats [59], while the others did not find significant changes in microbial composition between the two groups, and some even reported the opposite results. The relationship between the gut microbiome and metabolic disorders was first proven in the laboratory of Jeffrey I. Gordon at the Washington University School of Medicine in St. Louis. The authors demonstrated that leptin-resistant mice, characterized by increased appetite and obesity, have a deficiency of Bacteroidetes and an increased relative proportion of Firmicutes compared with control animals [60].
