The Fast Way to Long Life: Starve Every Other Day
By Jonathan Leake
Starving yourself every other day can make you live longer, American government scientists say.
They have discovered that a diet based on fasting on alternate days will not only help people to shed pounds but could delay age-related disease, boost brain power and extend lifespan.
 fasting 節食，禁食。
 pound 磅（重量單位），引申為體重。
The experimental diet, pioneered at the National Institutes on Aging (NIA), is based on the fact that animals given the bare minimum of calories required to maintain life can live up to twice as long.
Such diets appear to protect the heart, circulatory system and brain against age-related diseases, including Alzheimer’s. It was previously thought to have little relevance to humans because so few people would have the willpower to keep their calorie intake so low.
 circulatory system 血液循環系統。
However, scientists at the NIA have now found that fasting every second day is almost as effective, while still allowing dieters to eat what they like on days between fasts.
The idea has been tested on animals but the scientists who conducted the research have found similar evidence for humans.
“Dietary energy restriction extends lifespan and protects the brain and cardiovascular system against age-related disease,” said Mark Mattson, head of the laboratory of neurosciences at the NIA and professor of neuroscience at Johns Hopkins University in Baltimore.
 cardiovascular 心血管的。
 neurosciences 神經科學。
“We have found that dietary energy restriction, particularly when administered in intermittent bouts of major caloric restriction, such as alternative day fasting, activates cellular stress response pathways in neurons.”
 intermittent 間歇的。
 pathway 生物名詞，多用為信號通路（signal pathway），是指當細胞內要發生某種反應時，信號從細胞外到細胞內傳遞了一種信息，細胞要根據這種信息來做出反應的現象。
 neuron 神經元。
Such responses help rejuvenate the brain and so boost or protect cognitive powers and intelligence, said Matt-son.
In one set of experiments, Matt-son and his colleagues fed laboratory mice only on alternate days. They allowed other mice to eat daily. Both groups of animals were given unlimited access to food when they were permitted to eat and, over time, averaged the same overall calorie intake.
Mattson found, however, that the animals fed intermittently retained a higher sensitivity to insulin, the hormone which controls sugar levels in the blood after a meal or snack. This meant they needed to secrete less of the insulin, high levels of which have been found to be associated with lower brain power and a higher risk of diabetes.
 insulin 胰島素。
Intermittent feeding also improved the animals’ resistance to a neurotoxin that simulates Alzheimer’s disease. Mattson compared the brains of animals fed a low-calorie diet with those of animals that had eaten well. Calorie-restricted diets appeared to enhance the function of brain synapses – the junctions between brain cells that promote the generation of new cells and make them more resistant to stress.
 resistance 抗性。
 neurotoxin 神經毒素。
 synapse 突觸。
Calorie-restricted diet was also found to improve memory in older people. Cutting energy intake appears to inhibit the genes that promote ageing and switch on genes that slow ageing down.
Mattson practises what he preaches, limiting himself to no more than 2,000–2,200 calories a day.