## 1 Introduction  
Dysbiosis is defined as an imbalance in the intestinal microbiota composition and has been associated with obesity [1, 2] and other metabolic disorders such as type 2 diabetes or metabolic dysfunction-associated liver disease (MASLD) [3, 4, 5]. Conversely, some genera of bacteria or even specific bacterial strains--mainly lactic acid bacteria (LAB)--have been shown to produce beneficial effects, including weight loss, reduced inflammation, and healthier hormonal profiles. This has led to their consideration as possible probiotics of interest in metabolic diseases [6; 7]. In fact, probiotics--defined by the WHO as \"live organisms which, when administered in adequate amounts, confer a benefit to the host\"--are currently a hot topic in research as gut microbiota modulators for the prevention and/or treatment of metabolic syndrome and obesity. _Lactiplantibacillus plantarum_ is a Gram-positive LAB widely recognized for its health-promoting properties and versatility in industrial applications [8; 9; 10]. Regarding its use within the food industry, _L. plantarum_ is considered a safe probiotic with the ability to prolong food shelf life and improve flavor characteristics, and it shows antimicrobial and antioxidant properties [9]. Notably, _L. plantarum_ has emerged as a promising probiotic candidate for managing obesity and metabolic syndrome, supported by extensive evidence from studies in different rodent models and humans [10]. Thus, various strains of _L. plantarum_ have demonstrated beneficial effects such as the modulation of the gut microbiota, enhancement of gut barrier function, reduction in systemic inflammation, and improvement of metabolic markers, including fat accumulation reduction, the maintenance of glucose homeostasis and lipid metabolism [10; 11; 12; 13; 14; 15; 16; 17; 18]. These effects are attributed to its strong resilience in gastrointestinal conditions, its ability to adhere to the intestinal mucosa, and its role in regulating key metabolic hormones like leptin and adiponectin. Moreover, clinical trials suggest that the health benefits observed in animal models may translate to humans [19; 20]. Thus, evidence suggests that _L. plantarum_ supplementation can lead to a decreased body mass index in adults relative to placebo, and this effect is frequently accompanied by an improvement of obesity-related inflammatory markers [19]. However, differences in the effectiveness of different strains of this probiotic have been reported, which makes it difficult to obtain robust results. Although further clinical studies are needed to clarify strain-specific actions and optimal dosing, _L. plantarum_ stands out as a compelling candidate for adjunctive strategies in metabolic health. Several research groups are actively seeking new strains of _Lactiplantibacillus plantarum_ with potential probiotic effects against physiological and metabolic disturbances related to obesity. Importantly, beneficial properties such as the improvement in carbohydrate and lipid metabolism are often strain-specific. While many bacterial species exhibit general health-promoting effects, the efficacy and mechanisms of action can differ markedly between strains within the same species [21]. This variability affects their survival in gastrointestinal conditions, adhesion to the intestinal mucosa, immune modulation, and metabolic or antimicrobial activities. Therefore, thorough functional characterization--including both in vitro and in vivo assessments--is essential to identify the specific properties and molecular mechanisms of each probiotic strain before its application in human health. In this sense, the use of simple screening models such as _Caenorhabditis elegans_ makes it possible to analyze the effects of new probiotic strains on parameters related to the metabolic syndrome, such as lipogenesis, oxidative stress, aging and life expectancy, and unveil the molecular mechanisms behind these effects [22].