对大多数人来说，在一生中维持接近饥饿饮食的意志是渴望而不可及的。但通常上，短期内对卡路里摄入量的限制（比如“5:2”的轻断食法，一周内的5天正常进食，其余两天限制卡路里摄取量)将对人体的新陈代谢有很大的益处，它有助于控制肥胖和糖尿病。

Animal studies show a reliable extension in lifespan during intermittent fasting. Other studies have shown genetically altering the body’s ability to respond to insulin, which is released when we eat a meal, doubles lifespan in worms. A similar experiment in mice revealed a less dramatic, but a still significant, increase in lifespan of 18%.

通过对动物的研究显示，间歇性禁食有助于延长寿命。其他研究证明，从基因上改变身体对胰岛素的反应能力（当我们吃饭时会释放胰岛素），能使蠕虫的寿命延长一倍。虽然对小白鼠的类似实验没有得出如此戏剧性的结果，但该发现仍然意义重大。节食大约可以延长18%的寿命。

Early on, the effectiveness of restricting calories led scientists to hunt for genes that mediated these effects. In the late 1990s and early 2000s, scientists became interested in sirtuins – a class of enzymes that turn on defence mechanisms during starvation.

早些时候，限制卡路里摄入的显著效果使得科学家开始寻找调节这些效果的基因。在二十世纪九十年代末和二十世纪初期，科学家对去乙酰化酶颇感兴趣 ——这是一类在饥饿期间开启防御机制的酶。

Resveratrol is a compound found in red wine and considered a candidate for anti-ageing. from shutterstock.com

白藜芦醇是一种在红葡萄酒中发现的化合物，被认为是抗衰老的候选物。图片选自shutterstock.com

Drugs such as the now infamous compound resveratrol, present in red wine, can activate one member of the sirtuins, called SIRT1, to extend lifespan in mice and slow markers of ageing. The SIRT1 enzyme requires a fuel for its activity, called NAD+, the levels of which decline with old age.

某些药物，譬如现在声明狼藉的、存在于红葡萄酒中的化合物白藜芦醇，可以激活去乙酰化酶中的一个元素，j2直播，称为SIRT1，它可以延长老鼠的寿命并减缓衰老(生物)标记。 SIRT1酶需要一种被称为NAD +的活性燃料，其水平随着年龄的增长而下降。

Given the importance of NAD+ to SIRT1, the idea of raising NAD+ levels has attracted attention. But NAD+ is used by other cell processes that could be involved in ageing. For example, Dr. Jun Li recently showed NAD+ levels are essential to turning on DNA repair machinery, which wanes as we age. These findings could also be used to reduce DNA damage caused by radiation exposure – such as in childhood cancer survivors – and cosmic radiation encountered by astronauts in outer space.

鉴于NAD + SIRT1的重要性，提高NAD +水平的观念引起了人们的关注。 但NAD +被其他可能参与老化的细胞过程所使用。 例如，Li Jun博士最近表明，NAD +水平对于开发DNA修复机制至关重要，一般来说，随着年龄的增长，DNA修复机制逐渐消失。 这些发现也可用于减少暴露于辐射下所引起的DNA损伤，如儿童癌症幸存者以及宇宙航天员在外太空遇到的宇宙辐射等。

The long-term effects of restricting calories on ageing in humans have yet to be fully characterised, and such a study in humans would be difficult to perform.

限制卡路里对人类衰老的长期影响尚未得到充分表征，而对人类的这种研究将难以执行。

Protein restriction 限制蛋白质的摄入量

It may be that the anti-ageing effect of calorie restriction isn’t in overall calorie intake, but rather the intake of the protein component of diets. Researchers have measured health and lifespan in an array of diets with different ratios of protein to carbohydrate to fats. They discovered protein restriction, rather than overall calorie restriction, is more important to lifespan.

有一种可能是，限制卡路里的抗衰老效果不全是由通过限制卡路里总摄入量而实现的，它与饮食中的蛋白质成分提取量也有关。 研究人员测量了不同比例的蛋白质对碳水化合物，对脂肪的饮食序列，在健康和寿命之间的关系。 他们发现，限制蛋白质摄入量，而不是对总体热量进行限制，对于寿命来说更为重要。

Translated to human diets, this would be the exact opposite of the “paleo” diet, a high protein diet which emphasises meat and unprocessed vegetables over grains. The concept behind this diet is to mimic that of early paleolithic humans living a hunter-gatherer existence. It is worth noting, however, that paleolithic humans are thought to have had a lifespan of only 33 years.