中年发福，代谢不背锅

Core Viewpoint - The article discusses the phenomenon of middle-aged weight gain, highlighting that it is a common issue influenced by lifestyle choices rather than metabolic changes as people age [4][18][30]. Group 1: Prevalence of Middle-Aged Weight Gain - Middle-aged weight gain is a widespread phenomenon, with studies indicating significant increases in Body Mass Index (BMI) from the age of 30 onwards [5][6][8]. - Research shows that the average BMI for men and women increases notably after the age of 30, with men reaching their peak BMI between 30 and 49 years [9][21]. - A study of 7,283 residents in Jiangsu found that waist circumference increases significantly during middle age, with men averaging 84.9 cm and women 77.5 cm by their 30s [12][13]. Group 2: Factors Contributing to Weight Gain - The article argues that middle-aged weight gain is not primarily due to metabolic slowdown but rather lifestyle factors such as diet, alcohol consumption, and physical inactivity [18][30][41]. - Increased alcohol consumption is noted, with men aged 40-65 drinking an average of over 160 times a year, contributing to weight gain [37][39]. - Sedentary lifestyles are highlighted, with research indicating that an increase of 1.5 hours of sitting time can lead to significant increases in BMI and waist circumference [41]. Group 3: Psychological and Social Influences - Stress and emotional factors are discussed as contributors to weight gain, with increased cortisol levels linked to abdominal fat accumulation [44]. - The article mentions that many middle-aged individuals resort to emotional eating as a coping mechanism for stress, leading to further weight gain [44][45]. - The pressures of work and family life are cited as reasons for unhealthy eating habits and lack of exercise among middle-aged individuals [44][46].