Obesity: an evolutionary context.
Obesity: an evolutionary context.
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DOI：
10.1093/lifemeta/loac002
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
Elmquist, Joel K
中科院分区：
文献类型：
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作者：
Speakman, John R;Elmquist, Joel K
身体完全缺乏脂肪的人（脂肪营养不良/脂肪萎缩）和严重肥胖的人都表现出严重的代谢和其他健康问题。因此，将身体脂肪水平调节在这些限制之间似乎是适应性的。可以考虑两种不同的模型。更传统的是设定点 (SP)，其中水平围绕固定水平进行调节。另外，双重干预点（DIP）是一个可以容忍相当大的变化的系统，但在突破临界高或低水平时被激活。 DIP 系统似乎比 SP 更适合我们的经验，并且模型表明它更有可能已经进化。 DIP 系统的演变可能是由于两种截然不同的选择压力。在低端，我们可能被选择避免低水平的脂肪作为对抗饥饿的缓冲，避免疾病引起的厌食症，并支持繁殖。在高端，我们可能会因为被捕食的风险增加而被选择避免过度储存。这种控制上限似乎已经失效，因为我们中的一些人储存了大量的脂肪，对健康产生了严重的负面影响。为什么进化没有保护我们免受这个问题的困扰？一种可能性是，在我们的进化史中，我们大幅降低了被捕食的风险后，由于随机突变，保护系统慢慢崩溃了。偶然地，它在某些人身上比其他人更容易崩溃，面对现代食品过剩，这些人现在无法有效地控制体重。为了了解肥胖的进化背景，重要的是要将储存一些脂肪的适应性原因（即较低的干预点）与储存大量脂肪的非适应性原因（破碎的上部干预点）分开。 DIP 模型有几个后果，展示了我们如何理解肥胖问题以及当我们尝试治疗它时会发生什么。
People completely lacking body fat (lipodystrophy/lipoatrophy) and those with severe obesity both show profound metabolic and other health issues. Regulating levels of body fat somewhere between these limits would, therefore, appear to be adaptive. Two different models might be contemplated. More traditional is a set point (SP) where the levels are regulated around a fixed level. Alternatively, dual-intervention point (DIP) is a system that tolerates fairly wide variation but is activated when critically high or low levels are breached. The DIP system seems to fit our experience much better than an SP, and models suggest that it is more likely to have evolved. A DIP system may have evolved because of two contrasting selection pressures. At the lower end, we may have been selected to avoid low levels of fat as a buffer against starvation, to avoid disease-induced anorexia, and to support reproduction. At the upper end, we may have been selected to avoid excess storage because of the elevated risks of predation. This upper limit of control seems to have malfunctioned because some of us deposit large fat stores, with important negative health effects. Why has evolution not protected us against this problem? One possibility is that the protective system slowly fell apart due to random mutations after we dramatically reduced the risk of being predated during our evolutionary history. By chance, it fell apart more in some people than others, and these people are now unable to effectively manage their weight in the face of the modern food glut. To understand the evolutionary context of obesity, it is important to separate the adaptive reason for storing some fat (i.e. the lower intervention point), from the nonadaptive reason for storing lots of fat (a broken upper intervention point). The DIP model has several consequences, showing how we understand the obesity problem and what happens when we attempt to treat it.