近来，网上流行这么一句话：人这一生，大约就是吃九吨左右食物，谁先吃完谁先走…。接着专家又出来辟谣了，说人这一生不止吃九吨。

中国传统谚语称“吃饭七分饱，健康活到老”，让我们来看看最新的科学研究是怎么解释其中的机理的：

营养素获取与线粒体、细胞凋亡和肥胖的关系

Nutrient availability links mitochondria, apoptosis, and obesity

A review paper in Aging journal explored the link between nutrients, mitochondria and apoptosis with known and potential implications for age-related decline and metabolic syndromes. Mitochondria are the dominant source of the cellular energy requirements through oxidative phosphorylation, but they are also central players in apoptosis. Nutrient availability may have been the main evolutionary driving force behind these opposite mitochondrial functions: production of energy to sustain life and release of apoptotic proteins to trigger cell death.

详见：http://www.impactaging.com/papers/v4/n11/full/100505.html