以下文章来源于肥胖世界ObesityWorld ，作者肥胖世界 肥胖世界ObesityWorld . 《肥胖世界》Obesity World - 同步传真肥胖及代谢国际新学术进展，为医学减重临床、教研人员搭建一座与国际接轨的桥梁，「每医健」旗下内容平台。 你是否有这样的困惑：步入30或40岁后，腹部赘肉变得异常难缠？明明饮食比年轻时更加节制，运动也更为积极，腰围却依然不断扩张…… 别急着自责缺乏毅力！《Science》杂志最新研究揭示了中年发福、腹部脂肪难以消除的真相：我们内脏脂肪中存在一种特殊细胞，它们会随 着衰老过程变得异常活跃，大量促进脂肪生成。所以，中年腹部减肥困难，或许真不完全是你的错！ 中年发福的真相：不只是脂肪细胞变大那么简单 先抛出一个灵魂拷问：你的身材是如何逐渐"圆润"起来的？虽然炸鸡啤酒确实"功不可没"，但从生物学角度看，体重增加主要通过两种机制实 现： 脂肪细胞数量增加 单个脂肪细胞体积膨胀 传统观点认为，成年后脂肪细胞数量基本固定，体重上升主要是因为现有脂肪细胞"长胖"了。然而，这次小鼠实验却揭示了脂肪堆积的新秘 密：主要原因竟是新脂肪细胞大量生成！ 为深入探究，科学家对小鼠的成熟脂肪 ...

Core Viewpoint - The article emphasizes that the decline in physical fitness associated with aging, particularly at the age of 35, is more related to lifestyle choices rather than age itself. Regular physical training can help mitigate or even reverse this decline [1][2][12]. Group 1: Age and Physical Fitness - A report indicates that job applicants aged 35 and above have increased by 14.9% in 2020, highlighting a societal perception of declining physical and mental capabilities in this age group [1]. - The article discusses how physical fitness can be maintained or improved through training, with examples of individuals achieving significant fitness milestones at advanced ages [2][12]. - It notes that the average adult loses 3-8% of muscle mass every decade after 30, and maximum heart rate and oxygen uptake decline by about 1% annually [12]. Group 2: Psychological Impact of Aging - The psychological effects of aging, particularly anxiety related to physical decline, are more pronounced than the actual physiological changes [5][6]. - The article mentions that many individuals in their mid-30s experience increased body awareness and concerns about weight gain, often attributing it to aging rather than lifestyle factors [5][10]. - Chronic pain issues, such as neck pain, are becoming more common among younger adults, indicating a shift in health concerns related to sedentary lifestyles [6][10]. Group 3: Lifestyle Factors and Health - Research indicates that BMI changes in adults are more closely linked to socioeconomic factors and lifestyle choices rather than age-related metabolic decline [8][10]. - The article highlights that unhealthy habits, such as irregular eating and increased alcohol consumption, contribute significantly to weight gain and health issues in the 35+ demographic [10][12]. - It emphasizes that maintaining a regular exercise routine can counteract the negative effects of aging and improve overall health and fitness levels [12][18]. Group 4: Recommendations for Fitness - The World Health Organization recommends a combination of moderate-intensity aerobic exercise and strength training to combat age-related decline [18]. - Regular physical activity is shown to enhance heart function, maintain healthy weight, and improve mental focus [18]. - The article encourages individuals to adopt a proactive approach to fitness, suggesting that age should not be a barrier to maintaining or improving physical health [18].

Core Insights - The article discusses the phenomenon of increased fat accumulation in middle-aged individuals, particularly focusing on the role of adipose progenitor cells (APCs) and their enhanced ability to generate new fat cells as people age [1][3][6] Group 1: Mechanisms of Fat Accumulation - The increase in individual fat tissue occurs through two main processes: hypertrophy (enlargement of fat cells) and adipogenesis (generation of new fat cells) [3] - Contrary to previous beliefs that APCs decrease in proliferation with age, recent studies show that APCs in middle-aged individuals actually become more active, leading to increased fat cell generation [3][5] Group 2: Research Findings - In studies involving male mice aged 12 months (equivalent to approximately 45 years in humans), significant increases in body weight and fat tissue were observed, with visceral fat increasing by 4.6 times and subcutaneous fat by 2.8 times [3] - Over 80% of the fat cells in the visceral fat tissue of these older mice were newly generated, indicating a robust adipogenesis process [3] Group 3: Identification of New Cell Types - Researchers identified a new subgroup of adipose progenitor cells, termed CP-A cells, which emerge around 9 months of age in mice and peak at 12 months [5] - These CP-A cells exhibit strong proliferation and differentiation capabilities, contributing to the active generation of fat cells in middle-aged individuals [5][6] Group 4: Implications for Human Health - Similar CP-A cell populations were found in human adipose tissue, suggesting that humans may experience analogous changes in fat cell dynamics as they age [6] - The study identified the leukemia inhibitory factor receptor (LIFR) as a crucial molecule for fat generation in CP-A cells, indicating potential therapeutic targets for preventing middle-aged obesity [6]