In the early 20th Century, Arctic explorer Vilhjalmur Stefansson spent a collective five years eating just meat. This meant that his diet consisted of around 80% fat and 20% protein.

　　20世纪早期，北极探险家斯德凡森在五年的时间里只吃肉类，这意味着他的饮食是由近80%的脂肪和20%的蛋白质组成的。

　　Stefansson wanted to disprove those who argued that humans cannot survive if they only eat meat. But unfortunately for him, he very quickly became ill when he was eating lean meats without any fat. He developed "protein poisoning”, nicknamed “rabbit starvation”. His symptoms disappeared after he lowered his protein intake and he raised his fat intake.

　　斯德凡森想要反驳那些主张人类只吃肉活不下去的人。但不幸地是，当他只吃没有脂肪的瘦肉时，他很快就生病了。他发明了“蛋白质中毒说”，别名为“吃兔饥饿”。在他降低蛋白质摄入量，增加脂肪射入后，中毒症状消失了。

　　His early experiments are some of the few recorded cases of high protein intake having extreme adverse effects – but despite soaring sales of protein supplements, many of us are still unsure how much protein we need, how best to consume it, and if too much, or too little, is dangerous.

　　斯德凡森德早期实验，是高蛋白质摄入造成极端不良反应的少数有记录案例之一。但是，尽管蛋白质补充料销量激增，我们很多人仍不确定我们需要多少蛋白质，食用蛋白质的最佳量，摄入太多或者太少都是危险的。

　　Obesity rates doubling over the past two decades, we’re becoming increasingly conscious of what we’re eating. In recent years many of us have swapped white bread for brown and wholemeal bread and full-fat milk for skimmed. Taking centre stage in our health kick is protein, from protein balls, bars to enhanced protein versions of staple products, dominating supermarket shelves.

　　在过去的二十多年里，肥胖率成倍增长，我们越来越意识到我们在吃些什么。近些年来，我们许多人用黑面包或者全麦面包取代白面包，用脱脂奶取代全脂奶。我们健康问题的焦点成为蛋白质，从蛋白球，蛋白棒，到蛋白增强版主食，蛋白质占据了超市货架。

　　But some experts now argue that foods with inflated protein (and prices) are a waste of money.

　　但是，一些专家如今论证出，高蛋白食品是浪费钱。

　　Protein is essential for the body to grow and repair. Protein-rich food such as dairy, meat, eggs, fish and beans are broken down into amino acids in the stomach and absorbed in the small intestine, then the liver sorts out which amino acids the body needs. The rest is flushed out in our urine.

　　对于身体生长和修复来说，蛋白质是必须的。诸如奶制品，肉类，鸡蛋，鱼和豆子的高蛋白食品在胃里被分解为氨基酸，之后被小肠吸收，随后肝脏可以甄选出身体需要的氨基酸。剩余的随着尿液排出体外。

　　Adults who aren’t especially active are advised to eat roughly 0.75g of protein per day for each kilogram they weigh. On average, this is 55g for men and 45g for women – or two palm-sized portions of meat, fish, tofu, or nuts.

　　不经常运动的成年人每日蛋白质建议摄入量为体重每千克0.75克。男性平均摄入量为55克，女性为45克，也就是两手掌的肉类，鱼，豆腐，或者坚果。

　　Not getting enough protein can lead to hair loss, skin breakouts and weight loss. But these side effects are very rare, and largely only occur in those with eating disorders.

　　蛋白质摄入不足会导致脱发，裂皮和体重降低。但是这些副作用很罕见，大多只发生在那些有饮食功能失调的人身上。

　　Despite that, most of us have long associated protein with building muscle. This is accurate. Strength-based exercise causes a breakdown of protein in the muscle. For muscles to grow stronger, the proteins need to rebuild. A type of amino acid called leucine plays a particularly big part in triggering protein synthesis.

　　尽管如此，大部分人一直将蛋白质和增肌联系在一起。这是准确的。力量训练会造成肌肉蛋白质破裂。为了让肌肉长的更健壮，需要重塑肌肉。一种名为白胺酸的氨基酸在促进蛋白质合成上扮演着重要的角色。

　　Some experts even argue that not consuming protein post-workout could cause the breakdown of muscle to be higher than the synthesis. Supplement brands advise drinking protein shakes after a workout to help the growth and repair of muscle tissue.

　　一些专家甚至争论，锻炼后不摄入蛋白质会引发更多的肌肉破裂，而不是蛋白质合成。补充料品牌建议在锻炼之后引用蛋白质奶昔，帮助肌肉组织生长和修复。

　　Indeed, research on the muscle-building power of protein supplements is varied. A 2014 analysis of 36 papers found that protein supplements have no impact on lean mass and muscle strength with the first few weeks of training on individuals.

　　实际上，蛋白质补充料增肌能量研究结果不一。2014的一项针对36份论文的研究发现，蛋白质补充料对训练几周的个体来说，不会影响他们的瘦肌和肌肉力量。

　　Over time and if the training becomes harder, supplements can promote muscle growth. However, the paper also concludes that these changes have not been proven over the long term.

　　随着时间延长，训练强度加大，补充料可以促进肌肉增长。然而，论文也得出结论，这些变化无法被证明长期有效。

　　The risk of consuming too much protein is small, but the bigger risk might just be falling for overpriced products offering us more protein than we need. Some products labelled as high protein aren’t, and they’re quite expensive. Anyway, consuming more protein than need is wasteful in terms of money.

　　过量摄入蛋白质的风险很小，但是更大的风险可能是那些为我们提供过多蛋白质的高价产品。一些产品标有高蛋白含量，但其实并没有，它们非常昂贵。不论怎么说，过量摄入蛋白质是浪费钱。