Where Fat Goes When You Lose Weight 减肥后脂肪去哪儿了

健康专家和研究肥胖问题的学 者也搞不清楚。 11 如果我们跟踪记录下所有 摄 入 的 食 物 量， 而 不 仅 仅 纠 结于那些难以捉摸的千焦或热 卡，那么体重增减的原因就远 没有那么神秘了。 12 政 府 最 新 公 布 的 数 据 表 明，美国人每天消耗的食物和 饮料为 3.55 千克（125 盎司）。 其 中，430 克（ 约 15 盎 司 ） 为固体宏量营养素，17 克（0.6 盎 司 ） 是 纤 维， 其 余 3.11 千 克（110 盎司）是水。 13 没 有 提 到 的 是， 我 们 还 吸入了超过 660 克（23 盎司） 的氧气，这个数字对你的腰围 同样重要。 14 如果摄入体内的食物和水 为 3.55 千克（125 盎司），再加 上 660 克（23 盎司）氧气，那 么需要排出体外的物质应该是 4.2 千克（148 盎司），否则体 重就增加了。如果想减肥，那 必须排掉 4.1 千克以上的东西。 15 大多数美国人每天摄入的 碳 水 化 合 物、 脂 肪、 蛋 白 质 和酒精为 430 克（15.2 盎司）， 刚 好 产 生 770 克（27.1 盎 司 ） 二氧化碳及 290 克（10.2 盎司） 水（约一杯），还有约 31 克（1.1 盎司）以尿液形式排掉的尿素 及其他固体物质。
The enlightening facts about fat metabolism 5 The correct answer is that fat is con-
全世界的人都热衷于风行 一 时 的 节 食 法 和 减 肥， 但没有多少人知道每公斤脂肪 到底是如何从身上减掉的。 2 令人惊讶的是，连参与我 们调研的 150 名医生、营养师 和私人教练对健康的认知也存 在误区。最常见的误解便是， 脂肪都转化成了能量。这一看 法的问题在于，它违反了所有 化学反应都须遵循的物质守恒 定律。 3 有些受访者认为，脂肪转 化成了肌肉，这是不可能的。 还有些人认为，脂肪通过结肠 排出了中， 98% 的人解释不清脂肪是怎么 减掉的。 4 如果不是转化成了能量或 肌肉，也没有排出体外，那脂 肪去哪儿了？
1 fad 一时的风尚；短暂的狂热。 2 亦作 the law of conservation of mass（质量守恒定律）。
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verted to carbon dioxide and water. You exhale the carbon dioxide and the water mixes into your circulation until it’s lost as urine or sweat. 6 If you lose 10 pounds of fat, precisely 8.4 pounds comes out through your lungs and the remaining 1.6 pounds turns into water. In other words, nearly all the weight we lose is exhaled. 7 This surprises just about everyone, but actually, almost everything we eat comes back out via the lungs. Every carbohydrate you digest and nearly all the fats are converted to carbon dioxide and water. The same goes for alcohol. 8 Protein shares the same fate, except for the small part that turns into urea and other solids, which you excrete as urine. 9 The only thing in food that makes it to your colon undigested and intact is dietary fibre (think corn). Everything else you swallow is absorbed into your bloodstream and organs and, after that, it’s not going anywhere until you’ve vaporised it.
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Where Fat Goes When You Lose Weight
减肥后脂肪去哪儿了
文 / 鲁宾·米尔曼 安德鲁·布朗 译 / 左自强 审订 / 沛轩
By Ruben Meerman & Andrew Brown
The world is obsessed with fad1 diets and weight loss, yet few of us know how a kilogram of fat actually vanishes off the scales. 2 Even the 150 doctors, dietitians and personal trainers we surveyed shared this surprising gap in their health literacy. The most common misconception by far, was that fat is converted to energy. The problem with this theory is that it violates the law of conservation of matter2, which all chemical reactions obey. 3 Some respondents thought fat turns into muscle, which is impossible, and others assumed it escapes via the colon. Only three of our respondents gave the right answer, which means 98% of the health professionals in our survey could not explain how weight loss works. 4 So if not energy, muscles or the loo, where does fat go?
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about 31 grams (1.1 ounces) of urea and other solids excreted as urine. 16 An average 75kg (165 pounds) person’s resting metabolic rate (the rate at which the body uses energy when the person isn’t moving) produces about 590 grams (21 ounces) of carbon dioxide per day. No pill or potion you can buy will increase that figure, despite the bold claims you might have heard. 17 The good news is that you exhale 200 grams (7 ounces) of carbon dioxide while you’re fast asleep every night, so you’ve already breathed out a quarter of your daily target before you even step out of bed.
Kilograms in versus kilograms out 10 We all learn that “energy in equals energy out” in high school. But energy is a notoriously confusing concept, even among health professionals and scientists who study obesity. 11 The reason we gain or lose weight is much less mysterious if we keep track
“脂肪代谢”给出了答案 5 正确的答案是，脂肪转化 成了二氧化碳和水。二氧化碳 呼出体外，水则混入人体循环 系统，最终以尿液或汗水的形 式排出。 6 如果减掉的脂肪为 10 磅， 准确地说，8.4 磅是通过肺部 排掉的，剩下的 1.6 磅变成了 水。换句话说，我们减掉的体 重几乎都是通过呼吸排掉的。 7 这大概会让所有人都大为 惊讶，但事实上，我们吃的几 乎所有东西最终都是通过肺部 排出的。人体消化的各种碳水 化合物和几乎所有的脂肪都转 化成了二氧化碳和水。酒精也 是如此。 8 蛋白质也基本一样，只有 一小部分会转化成尿素和其他 固体物质，以尿液的形式排出 体外。 9 食物中唯一可以不经消 化、原样进入结肠的东西就是 膳食纤维（比如玉米）。吃下 的其他东西都会被吸收进血液 和器官，之后，哪儿也不会去， 直到被蒸发掉。
进出平衡 10 我们都在高中学过“能量 守恒”的知识。但能量是一个 极其令人困惑的概念，连一些
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of all the kilograms, too, not just those enigmatic kilojoules or calories. 12 According to the latest government figures, Americans consume 3.55 kg (125 ounces) of food and beverages every day. Of that, 430 grams (about 15 ounces) is solid macronutrients, 17 grams (0.6 ounces) is fibre and the remaining 3.11 kg (110 ounces) is water. 13 What’s not reported is that we inhale more than 660 grams (23 ounces) worth of oxygen, too, and this figure is equally important for your waistline. 14 If you put 3.55 kg (125 ounces) of food and water into your body, plus 660 grams of oxygen (23 ounces), then 4.2 kg (148 ounces) of stuff needs to come back out, or you’ll gain weight. If you’re hoping to shed some weight, more than 4.1kg will have to go. 15 The 430 grams (15.2 ounces) of carbohydrates, fats, protein and alcohol most Americans eat every day will produce exactly 770 grams (27.1 ounces) of carbon dioxide plus 290 grams (10.2 ounces) of water (about one cup) and