正文
5-2 diet
”
, requires people to eat either very small amounts, or nothing at all, on two days a week, but imposes no restrictions on the other five.
减肥方法层出不穷。时下最流行的当属
"
间歇性禁食
"——
顾名思义，就是将进食时间限定在特定时段。其中
"5-2
轻断食法
"
颇受欢迎，要求每周两天仅少量进食或完全禁食，其余五天则无需限制。
Intermittent fasting is popular. And as a weight-loss strategy, it has several things going for it. One is that it is uncomplicated. There is no need to weigh the ingredients of every meal, as some diets demand, nor to change what you eat
drastically
. Limiting the restrictions to a couple of days a week, or several hours a day (most of which are spent asleep) also requires less
willpower
, which might make it easier to stick with.
这种饮食方式大行其道。作为减重策略，它具备多项优势。其一，操作简单。无需像某些饮食法那样精确称量每餐食材，也无需彻底改变饮食结构。每周仅需坚持数天，或每天限制数小时（大部分时间在睡眠中度过），意志力的消耗相对较少，因此更易长期坚持。
Working out whether that actually translates into greater weight loss than other diets is difficult. Most studies find limited data and mixed results. The general consensus, says Nichola Ludlam-Raine, a dietitian and spokeswoman for the British Dietetic Association, is that intermittent fasting seems to work roughly as well for weight loss as traditional calorie-counting does.
但要验证其减重效果是否优于其他饮食法却非易事。多数研究数据有限且结果不一。英国饮食协会发言人、营养学家尼古拉
·
拉德拉姆
-
雷恩指出，学界普遍认为间歇性禁食与传统热量控制法在减重效果上大致相当。
Other health benefits might also beckon. Forcing lab animals to fast (albeit not intermittently) can increase their lifespans by up to 40%. It also appears to
mitigate
the physical decline that comes with old age, boost various markers of metabolic health and even reduce susceptibility to cancer.
该饮食法可能还具备其他健康裨益。实验室动物强制禁食（尽管不是间歇性禁食）可延长寿命达
40%
，同时能延缓机体衰老、改善代谢指标，甚至降低患癌风险。
Exactly how it does all that is not entirely clear. One important factor seems to be autophagy, the process by which cells break down and recycle parts of themselves. Cells become much keener on autophagy when nutrients are scarce.
具体作用机制尚未完全阐明。一个重要因素可能是细胞自噬机制
——
即细胞分解并回收自身部分结构的过程。当营养匮乏时，细胞自噬活动显著增强。
At the same time, autophagy seems to have a preference for attacking damaged and degraded parts of cells—
and the accumulation of such cellular detritus is one of several mechanisms thought to underlie the
decrepitude
that comes with ageing.
同时，这种机制优先清除细胞内的受损老化部分，而此类细胞碎片的堆积正是导致衰老的重要因素。
