Obesity and overweight have increased at an alarming rate in the world during the last three decades. Obesity is a crucial factor in the development of metabolic abnormalities, including glucose intolerance, insulin resistance, metabolic syndrome, low-grade inflammation and oxidative stress. A similar scinario occurs during the aging process where alterations of the energetic metabolism homeostasis and a chronic systematic low-grade inflammation have been observed. Oxidative stress and poor physical performance can increase the risk of metabolic disease. Despite the diverse studies on the pathophysiological effects of obesity, its impact related to gender and through life, particularly during aging, hasn't received a reasonable attention. The purpose of this review is to outline the pathophysiological mechanisms and metabolic alterations associated with obesity, with an emphasis on the monosodium glutamate (MSG)-induced obese model. MSG-induced obesity associated inflammation and declined adiponectin were more obvious in male mice, while glucose tolerance, insulin sensitivity and the redox balance were altered with increased age of both male and female mice. These findings indicate that the metabolic alterations in MSG-induced obesity are associated with the gender as well as aging. Therefore, the MSG obesity model is of a resonable value to underlie the relationship between gender, aging and metabolic alterations in obesity. In addition, we reviewed the medicinal plants and their active constituents which have been used to treat MSG-induced obesity. Given the significat value of this model, studies are needed to scrutinize the benificial effects and underlying mechanisms of medicinal plants with proven anti-obesity activity.

Obesity, from children to the elderly, has increased in the world at an alarming rate over the past three decades, implying long-term detrimental consequences for individual’s health. Obesity and aging are known to be risk factors for metabolic disorder development, insulin resistance and inflammation, but their relationship is not fully understood. Prevention and appropriate therapies for metabolic disorders and physical disabilities in older adults have become a major public health challenge. Hence, the aim of this study was to evaluate inflammation markers, biochemical parameters and glucose homeostasis during the obese-aging process, to understand the relationship between obesity and health span during the lifetime. In order to do this, the monosodium glutamate (MSG) obesity mice model was used, and data were evaluated at 4, 8, 12, 16 and 20 months in both female and male mice. Our results showed that obesity was a major factor contributing to premature alterations in MSG-treated mice metabolism; however, at older ages, obesity effects were attenuated and MSG-mice became more similar to normal mice. At a younger age (four months old), the Lee index, triglycerides, total cholesterol, TNF-α and transaminases levels increased; while adiponectin decreased and glucose tolerance and insulin sensitivity levels were remarkably altered. However, from 16 months old-on, the Lee index and TNF-α levels diminished significantly, while adiponectin increased, and glucose and insulin homeostasis was recovered. In summary, MSG-treated obese mice showed metabolic changes and differential susceptibility by gender throughout life and during the aging process. Understanding metabolic differences between genders during the lifespan will allow the discovery of specific preventive treatment strategies for chronic diseases and functional decline.