[Rodent models of diet-induced obesity and sedentary lifestyle]

Obesity and a sedentary lifestyle are serious medical and social problems. Experimental modeling of these pathologies is necessary to understand their mechanisms and develop new treatments. The objective of this study was to summarize in the form of a narrative review information on experimental models of diet-induced obesity, sedentary lifestyle and pathogenetically associated disorders in rodents.

A literature search was conducted across the eLibrary, PubMed, Web of Science, and Scopus databases in recent years. The search strategy utilized the following keywords: obesity, metabolic syndrome, rodents, rats, mice, experimental models, rodent models, diet-induced obesity, high-fat diet, high-fructose diet, high-fat high-fructose diet, high-sucrose diet, sedentary lifestyle, physical inactivity. A total of 70 publications were selected from the last 5 years (2021-2025), excluding articles of fundamental importance.

Among diet-induced obesity modeling approaches, high-fat diet (40-60% of total calorie intake) is the most prevalent, utilized in over 75% of related studies. Alternative approaches include carbohydrate-enriched diets (specifically high-fructose) and various combination. Notably, body mass gain is not observed in all subjects, a challenge compounded by the lack of a unified somatometric standard for rodent obesity. Furthermore, biochemical markers associated with obesity fail to manifest in at least 20% of such experiments. This variability - beyond physiological interspecies differences and genetic predisposition - is primarily attributed to the high heterogeneity of experimental protocols. While such diversity is acceptable in exploratory research, the translational application of alimentary models (e.g., preclinical trials) necessitates rigorous standardization. Consequently, further refinement and validation of these models are required, accounting for dietary composition and auxiliary factors. Reduced physical activity is a critical yet less explored variable, whereas healthy rodents typically exhibit high voluntary activity, covering up to 5-10 km per day on a running wheel. Modeling sedentary behavior - both in isolation and in combination with hypercaloric intake - remains less established than purely diet-induced approaches. Promising and technically accessible methods for simulating a sedentary lifestyle include locking the running wheel and reducing the cage size. Conversely, providing enriched activity environments for control groups is essential to maintain baseline metabolic homeostasis.

Rodent models of obesity - most commonly established through high-fat diets (75% of studies) and/or high-carbohydrate regimens - suffer from significant protocol heterogeneity. To improve the translational validity of these models, further standardization is essential. In particular, sedentary behavior should be addressed as a critical dietary cofactor, as it can be easily integrated into experimental designs.