Very "Chiamp", the more I read, the more blur i become:(
Fuel on Fat For the Long Run
燃烧体脂肪作为长跑的能量
By Deborah Schulman, Ph.D
译者张开云
It Is More Efficient To Tap Into Your Unlimited Fat Supply
利用你的体脂供应无限能量会更有效率
© 2000 42K(+) Press, Inc.
MIGRATORY BIRDS and whales rely on stored fat to fuel their long, strenuous journeys. Developing your fat engine will increase the amount of energy you can generate, reduce the amount of carbohydrates you use, and stretch out the glycogen supply during long runs. Added together, you have a more stable and enduring energy supply, better endurance, and faster finish times.
候鸟和鲸靠着燃烧体内储存的脂肪完成漫长艰辛的迁陡。长跑时，开发你体内的「燃脂引擎」能提高产生能量的总值，减少碳水化合物的消耗，延长肝醣的供应。总合以上的能源，你将有更稳定且持久的能量供给，更有耐力，更快完跑。
To illustrate, let's consider Shane. Shane is a computer engineer in his late 30s who has stayed active over the years with yard work, occasional football games with his kids, and sporadic attempts to weight train. In short, he was not aerobically fit. Inspired by the fortitude and tenacity of his wife, who just ran her first marathon, he decided to train for a marathon.
就拿贤哥作例子来说明。贤哥是位电脑工程师，30 岁，多年来用整理庭院的劳动保持活力。偶而和孩子玩美式足球，极少尝试激烈运动。总而言之，他并不具备健康的心肺功能。受到他刚 完成第一个马拉松的老婆所展现之毅力和坚持所刺激，贤哥决心进行马拉松训练。
He was determined to be informed and methodical about the process. Many of the books he read recommended training with a heart rate monitor. The books said that most people run marathons at 75 to 80 percent of maximum heart rate, so he decided to do a test. He consulted a chart to find his heart rate at a more manageable effort of 65 percent and set off running.
他决定要暸解整个训练流程并有条不紊地进行。许多书都推荐心跳监控训练法。书上说大多数人跑马拉松时心跳达到最高心跳的75~80%，因此他决定做个验证。他查表后发现心跳保持在最高心跳的65%有较易掌握的效果，就按此要领进行训练。
After only 90 minutes on the road, he felt nauseated and fatigued. His legs felt like bricks, and finally he was forced to stop. In other words, he bonked well short of the distance he would need to cover to finish the marathon.
上路一个半小时后贤哥感觉很虚并且想吐。他因为「铁腿」不得不停下来。换句话说，他「撞墙」得有够早，根本无望撑完马拉松的距离 。
Due to his low level of fitness, most of Shane's energy was coming from the limited carbohydrate stores in his liver and muscles. He simply ran to the end of his carbohydrate supply. Carbohydrates are necessary to maintain exercise at any intensity. An excessively high rate of usage combined with low carbohydrate stores reduced his endurance, even at relatively easy running speeds. Had he eaten GU or drunk Gatorade, he still would not have been able to continue for much longer. A training program that focused on switching to fat for fuel would change that.
由于他如此逊的体能，贤哥所有的能量来自储存在肝脏和肌肉中的醣。他轻易地耗尽体内的醣。碳水化合物也就是醣是维持任何强度运动 的必需能源。过度高比例的消耗再加上低存量降低贤哥的耐力，即使用轻松跑的速度也一样。就算吃 能量包或运动饮料依然无法撑久一点儿。因此训练计画的重点在转换脂肪作为能源来改善这现象。
PUMP UP THE VOLUME 提高训练份量
Arthur Lydiard contended that the most important aspect of conditioning is volume. In the 1960s his training concepts were revolutionary. Even the track athletes whom he coached followed a marathon-based aerobic conditioning program in the initial phases of their training cycles. Considering the phenomenal success of athletes who trained under Lydiard's tutelage, such as Peter Snell, John Davies, and Lorraine Moller, and other athletes who have followed his program principles, his theories were insightful. Subsequent research has shown that they also possess a sound physiological basis.
Arthur Lydiard主张调整状态时最重要的面向是训练份量。他的训练观念在60 年代是革命性的。即使是他带的径赛选手，在训练周期的最初阶段也必须先遵循如马拉松训练式地调整心肺有氧课程。看看在他的调教下 那些成就非凡的运动员就知道他的理论是真知卓见。随后所作的研究也显示他的理论具有完整的生理学基础。
While many of America's marathoners switched focus to quality (and reduced mileage) rather than quantity, coaches from Japan, Italy, Mexico, Germany, and China were incorporating Lydiard's principles into highly successful training programs. Naoko Takahashi reportedly ran up to 80K (50 miles) per day in preparation to become the first woman marathoner in the world to dip under 2:20. Catherine Ndereba ran comparatively modest 100-mile weeks in the buildup to her world record of 2:18:47 at Chicago in 2001. Jerry Lawson, imitating the high-mileage successes of Bill Rodgers, Alberto Salazar, and Frank Shorter, ran up to 250 miles per week en route to his then American record of 2:09.
当许多美国的马拉松选手转变训练重点为重质不重量(并减少里程数)时，日、义、墨、德、中国的教练们引用Arthur Lydiard的原理在他们非常成功的训练计画中。高桥尚子的训练量每日高达80公里并破记录地成为第一个跑进2小时20分的女子马拉松选手。Catherine Ndereba较谨慎地每周跑100英哩，用数周累积里程来创下2001年世界纪录2:18:47在芝加哥。Jerry Lawson仿效Bill Rodgers, Alberto Salazar, and Frank Shorter高里程训练的成功经验，在达成他的美国纪录2:09的过程中，提高周里程数到250英哩。
Metabolically, high-volume training makes sense. There are two main sources of fuel for exercise: carbohydrates and fats. The energy supply from carbohydrate and fat is inversely related. High rates of carbohydrate use reduce combustion of fat. Carbohydrates are used preferentially at very high efforts, such as a 5K race, or at low fitness levels when fat metabolism is underdeveloped.
以新陈代谢的角度来看，大量训练是合理的。有两种主要能源作为运动的能量: 醣和脂肪。这两种能源的供应是逆转换的关系。高比例地消耗醣类会减少脂肪的燃烧。碳水化合物会优先消耗于高速的运动，如5公里短程竞速或脂肪代谢尚未开发之低阶的体适能状态。
Conversely, when you teach your body to rely on fat for fuel, your combustion of carbohydrates goes down, thus "sparing" carbohydrates. This benefits performance in endurance events. You become very fatigued when you run too low on carbohydrates. We store only a very limited amount of carbohydrate (glycogen) in our bodies. Compare this with a relatively unlimited supply of fat. Even an athlete with only 6 percent body fat will have enough fat to fuel exercise lasting for many hours. When you use more fat, you generate more energy and your carbohydrate supply lasts longer.
相对的，当你训练自已的身体以脂肪为能源，体内醣的消耗就降低，甚至变成备用能量。这种好处表现在持久力上。体内醣的储量过低会 使人变得很虚。人体只能储存非常有限量的醣(肝醣)。相较于脂肪则用之不尽。就算只有6%体脂肪的运动选手也有足够的能量支撑数小时的运动。当你利用愈多的体脂肪，不但能产生更多的能量，更能延长醣的消耗。
Follow the principle of specificity. If you want to teach your body to use more fat for fuel, then create training conditions that generate high fat metabolism. Your body will eventually learn to prefer fat.
依据上述的原理，假使你想训练自已的身体利用更多体脂作为能源，只要创造能提高体脂肪新陈代谢的训练条件，身体就会学习利用脂肪 。
Research conducted at the Karolinska Institute in Sweden during the 1980s showed that, within the leg muscles of highly trained endurance men, the activity of enzymes that break down fats was 100 percent higher than in the untrained subjects. As a result, during exercise they had a much higher ability to regenerate the ATP that fuels muscular contraction than those who had a greater reliance on carbohydrates.
在瑞典的Karolinska 中心进行的研究显示，经过耐力训练的男子大腿肌肉中，其酵素分解脂肪的效率高于未经训练者的一倍。因此，这些酵素在运动时比主要 依赖醣代谢的酵素有较高的能力再生肌肉收缩所需的ATP。
These researchers found that the maximal oxygen consumption (or V.O2max) was 50 percent greater in the trained men. Maximal oxygen consumption measures aerobic capacity: the efficiency of the lungs to transfer oxygen to the blood, the capacity of the blood to carry oxygen, the power of the heart and blood vessels to deliver large quantities of blood to the muscles, and the ability of the muscles to use the oxygen. Fats cannot be burned without oxygen. Not only did these men have more enzymes to combust the fat, but they also had more oxygen to feed the fire.
这群研究者发现耐力训练过的人，他的最大耗氧量(V.O2max)也提高50%。最大耗氧量用来测量换氧能力: 包括肺的工作效率，血液的载氧量，心脏和血管的送血量和肌肉使用氧的能力。脂肪燃烧不能缺氧，这些经过耐力训练的人不仅有较多的 酵素燃烧脂肪，也有较多的氧气供应。
Researchers have since demonstrated that, after a 12-week six-day-per-week program of 45 minutes of running and cycling at a high intensity, fat combustion increased by 41 percent. This was accompanied by reduced reliance on carbohydrates.
研究者曾展示经过12周，每周六天，每天45分钟高强度的跑步和自行车的训练，脂肪的燃烧增加41%，同时也降低对醣的依赖。
MILES MAKE MITOCHONDRIA 里程数制造粒腺体
The enzymes of fat metabolism are located in structures within the muscle cells called mitochondria. Fats are transported into the mitochondria where, in the presence of oxygen, they are broken down to generate energy. More mitochondria means more fat metabolism, more ATP, and more energy.
代谢脂肪的酵素存在于肌肉细胞里称为粒腺体的组织中，脂肪被传送进粒腺体中，只要有氧的存在便作用产生能量。愈多的粒腺体表示愈 多的脂肪的代谢，产生愈多的ATP就有愈多的能量。
High-volume training increases the amount and size of mitochondria. Longer exercise bouts produce the greatest gains in mitochondrial content. A 90-minute run provides a better stimulus than a 60-minute run. It is common for runners to do "two-a-day" workouts to get in the necessary mileage. However, this research indicates that a runner will receive much more benefit from running one 90-minute workout than two 45-minute workouts. There is, however, a point of diminishing returns. A three-hour run is better at nudging the mitochondria content upward than a 90-minute run, but the gains are offset by the necessity of a longer recovery time between workouts.
大量训练会增加粒腺体的数量和尺寸。愈长时间的运动可加速产生新陈代谢中的益处。跑90分钟比跑60分钟产生更好的刺激。为了累积里程数跑者一天练跑两趟是很平常的现象，可是此研究指出跑一趟90分钟的效果好过跑两趟45分钟的训练。但也不是意味着可以无限制的增长时间，必定有个极限。3小时的长跑固然比跑90分钟有利于提升代谢的效果，但成效会被操练之间所需更长的恢复时间所抵消。
During the base phase of building miles, it is the daily consistency of training over a period of weeks and months that will boost fat metabolism.
在累积里程数的最初阶段，要提升脂肪代谢率要每天密集的训练数周或数月。
After the base phase and basic fat metabolism have been established, training time should be shifted into very prolonged runs of three or more hours, depending on your event. Very long runs are important in preparation for the marathon and longer events. After two to three hours of running, the leg muscles run low on glycogen. Hormonal adjustments to the low glycogen levels shift fat metabolism into an even higher gear.
经过最初的阶段后而且基本的脂肪代谢机制己被建立，训练时间即可延长至3小时以上的超长跑，视你准备挑战的距离而定。超长跑在准备马拉松或超马时是非常重要的。经过2、3小时的长跑后，腿部肌肉消耗很少的肝醣，内分泌的机转会降低肝醣并提高脂肪的代谢使身体进入高速省油档。
Miles may make champions, but those miles should be carefully developed, monitored, and arranged to get the maximum effect. In his buildup program, Lydiard recommends alternating longer 90-minute to two-hour runs with 60-minute runs on other days, aiming for a total of 10 to 11 hours of weekly running.
里程可以赢得锦标，但必须小心地累进，被监测和妥善安排方能获得最佳训练成效。在Lydiard的里程累积计画中，他建议用2小时长跑撘配隔天1小时的方式来取代90分钟的长跑，来达成10~11小时的周里程数。
Give yourself plenty of time to build up to these levels. Jon Sinclair, former world-class runner turned coach, cautions that it is not practical or even possible for most people with full-time jobs and families to build up to running 10 hours per week in a mere three months. The amount of mileage you will be able to run depends on your lifestyle, physical capabilities, and prior training history. He advises his less-experienced athletes to build up mileage over a period of many months or even years. His associate, Kent Oglesby, took four years to prepare a 3:15 marathoner for the rigors of running 100 miles per week. The result was a 2:46 marathon, which earned her a spot at the U.S. Olympic Marathon Trials.
给自己充份的时间达到这样的水准。Jon Sinclair，前世界顶尖跑者现转任教练，指出要大多数的上班族及有家庭的人做到3个月每周累积10 小时的里程数是不实际甚至不可能。每个人能跑的里程数要视生活型态、生理的负荷及先前训练的情况而定。他建议较没经验的跑者多用 几个月或几年来建立个人的里程数。他的副手Kent Oglesby用4年时间累进至每周100英哩的严格训练来准备挑战3:15的马拉松。比赛结果2小时46分使她成为美国奥运选拻赛的焦点。
TRAIN AT THE TOP OF YOUR FAT-BURNING ZONE 在体脂肪代谢的最顶点作训练
My speed in long races had been declining since I had become a masters runner. For a number of years I had been running LSD (long, slow distance) type training. In the process of researching and writing about fat metabolism, I read Lydiard's book Running the
Lydiard Way
. Lydiard's formula advocates not just high-volume training but high volume at speeds near the "maximum steady state."
我长跑的速度自从我成为老练的跑者后就衰退。多年以来我都采LSD(长、慢、距离)式训练法。当研究脂肪的新陈代谢时，我研读Lydiard的著作Running the Lydiard Way，他的法则倡导不仅要高训练量还要够份量的速度训练以接近最高均速的状态。
In other words, most training should be conducted close to the highest speed that you can run without going anaerobic. This is the speed where fat metabolism is at its highest. For experienced runners, the maximum steady state equals an intensity of 70 to 75 percent of maximum heart rate. For those just launching their running careers, it will be closer to 60 to 65 percent of maximum heart rate. Studies have confirmed his theories. Volume and intensity interact to produce even greater gains in mitochondria development. Daily runs of 90 minutes at 70 percent max will boost mitochondria 30 percent higher than equivalent time spent at an easier 50 percent effort.
换句话说，所有的训练都该要求接近不形成氧债的最高速度，这也是脂肪代谢的顶点。对老手而言，最高均速状态相当于70~75%最高心跳的强度，对新手而言，约为60~65%最高心跳。研究已经证实他的理论，训练量和强度交互作用对新陈代谢的发展产生更大的效果。用70%最高心跳的强度每天跑90分钟相较于相同时间只用50%的最高心跳强度可提高30%新陈代谢的效果。
After purchasing a heart rate monitor and calculating my target heart rates, I was surprised to find that my LSD training intensity had been substantially below my target training intensity of 70 percent. Initially I had a hard time running more than 60 minutes at that effort. However, after only six weeks of faster training, I was easily able to maintain that pace for a full two hours. Although LSD training will increase fat metabolism and endurance, it will limit your endurance at marathon paces. Long, slow running will only teach you to run slowly for long periods.
当我买了心跳计并计算我的目标心跳后，我惊讶的发现LSD训练强度事实上低于70%最高心跳的强度。起先我想保持目标强度超过60分钟都令我吃足苦头，然而只经过6周较怏速度的训练，我就能轻松地维持速度超过2小时。虽然LSD式训练法提高脂肪代谢和耐力，但也会限制你的耐力在马拉松的配速。长、慢跑只会教你的身体跑慢和跑久。
On the other hand, you can run too fast on your daily runs. At faster paces, oxygen demand exceeds supply. You are now anaerobic. Fuel reliance switches predominantly to carbohydrates, and the result is the accumulation of lactic acid. Lactic acid inhibits the enzymes that break down fat and therefore reduces fat metabolism. If you go out for a 45-minute run at 10K race pace, you will be burning less fat and generating more waste products than if you ran those 45 minutes at only a 60 percent effort. Daily hard efforts will result in accumulation of waste products and decreased recovery, and lead to declining performances. It's better to run a little too slow than a little too fast.
另一方面，你也可能在每日练跑时跑太怏。在较怏的速度下，氧气供不应求。这时你处于氧债的状态，能量供给会转向醣类，结果也造成 乳酸的累积。乳酸阻止酵素分解脂肪也就降低脂肪的代谢。假使用10K的速度跑45分钟，将会比60% 强度跑相同时间消耗较少脂肪及产生更多的废物。每天苦操将造成体内废物的累积和延缓恢复，也会导致体能状况衰退。稍微慢一些总好 过太怏一些。
RAISE THE LACTATE THRESHOLD 提高乳酸门槛
Let's return to Shane after 24 weeks on his Lydiard-based training program. His fat metabolism is augmented, there is a substantially reduced reliance on glycogen, and his glycogen stores are larger. He again decides to test his ability to run at 65 percent of his maximum. Before the test he makes sure to get plenty of carbohydrates in his diet so that his leg muscles and liver are loaded with glycogen. This time he was able to continue for three hours.
回头再看贤哥经过24周Lydiard式的训练成果。他的脂肪代谢提高，也降低消耗肝醣，并且身体中肝醣的储量也增加。他决定再次用65%的强度进行测试。测试前他刻意在饮食中摄取大量的碳水化合物以确保他的肌肉和肝脏中储存足够的肝醣。这次他持续跑了3小时。
His skeletal, connective, and muscle tissues; his metabolism; and his cardiovascular, nervous, and endocrine systems are now prepared for some faster training. His next step is to focus on increasing his endurance running speed and reducing his lactate production.
他的骨胳、结缔和肌肉组织，他的新陈代谢，他的心脏及血管系统，神经和内分泌系统都己准备好迎接更快的速度训练。下一步训练的重 点就是提升耐力跑的速度及减少乳酸的产生。
Endurance races are aerobic races. Marathons tend to be run at just below the level where you start to accumulate lactic acid, which is known as the anaerobic threshold (AT). How many times have you started a race too fast and gone anaerobic, only to suffer later and run slower than you planned or even had to drop out?
耐力跑是有氧运动，马拉松倾向保持跑在开始累积乳酸的运动程度之下，亦即所谓的氧债门槛(AT)。还记得自己曾经多少次因起步太快形成氧债运动后，不得不忍受肌肉酸痛举步维艰地苦撑「慢跑」，甚至中途放弃。
With a higher AT, you will be able to sustain faster marathon and ultramarathon paces. Elite world-class marathoners often have such a highly developed fat-burning engine that they can run marathons at 85 percent or higher of their maximum. For the rest of us, 75 to 80 percent is a realistic goal.
若有较高的氧债门槛，你能维持较快的马拉松和超马的配速。顶尖的世界级马拉松选手通常具备高效能的脂肪代谢能力，使他们能用85%甚至更高的最高心跳来跑马拉松。其余如我辈之跑者，75~80%才是我们追求的目标。
Anaerobic threshold training augments the basic fat metabolism you have spent so much time developing. The result is faster running speeds over the long haul. A measured dose of faster, anaerobic training will teach your muscles and blood to metabolize and buffer lactic acid. The goal is to generate a manageable quantity of lactic acid that your muscles can dispose of easily and permit a sufficiently long training session and quick recovery. Venturing too far into the anaerobic zone will generate too much lactic acid, reduce the amount of work you can do within your training session, and risk lasting fatigue and overreaching. Marathoners don't derive much benefit from 400-meter repeats.
氧债门槛的训练能加强你费时很久建立的脂肪代谢的能力。训练成果是更快的速度完成长远的路程。一种经计算过份量和频次的氧债速度 训练能使你的肌肉和血液代谢和缓解乳酸。训练目的要产生你的肌肉可以轻易处理之适量的乳酸，并容许足够时间的长期训练及快速恢复 。投入太多氧债区的运动会产生太多乳酸，降低在此期间的训练量，并导致疲劳持续和训练过量的风险。马拉松跑者不会从 4百米反复跑中得到助益。
Faster, sustained running at 80 to 85 percent and mile repeats are good methods to increase lactate tolerance. Oglesby recommends tempo runs of 10 to 12 miles at 15 to 30 seconds per mile faster than goal marathon race pace. An added benefit of these tempo runs is that the marathon pace feels easier and more manageable.
较快速的持久跑在80~85%强度并以1英哩作反复跑是很好的方法来提高乳酸耐受力。Oglesby建议用比跑马拉松的目标速度每英哩快15~30秒的配速做10~12英哩的间歇跑。如此训练的附加价值会令你跑马时更轻松自在。
A recent study examined the effect of high-intensity interval sessions on fat and carbohydrate metabolism and lactate concentrations in cyclists who had been training two to three hours per day for years. They replaced some of their endurance miles with two weekly sessions of 6-9 x 5-minute intervals with 1 minute of recovery between. After six weeks, the percentage of energy coming from fat during a one-hour trial had increased from 6 percent to 13 percent. How well this applies to a race lasting more than two hours is unclear.
最近的研究证明经年累月每天训练2~3小时的自行车手接受高强度间歇训练后在脂肪和醣的代谢与乳酸浓缩的成效。他们每两周一次以6-9趟5分钟间歇训练，间隔1分钟休息来取代耐力训练。经过6周后，当1小时竞速时，脂肪供给能量的比例从6%提高到13%。至于对超过2小时比赛的改善就不明显。
Because of the results from studies on interval training such as these, many runners have opted out of the extended base-building phase citing "quality over quantity" as the rationale. I would like to emphasize that high-intensity training builds on the increased strength, resilience, and fat metabolism developed during those long, high-quality aerobic miles. Jumping into AT training before your body is sufficiently prepared will not produce the desired results: fast marathons.
因为这些研究的结果，许多跑者就断章取义地截取延伸训练的部份视之为「重质不重量」的理论。我必须强调这种高强度的训练必要的前 提，是由长期高素质有氧训练累积的里程数所产生的肌力、弹性和脂肪代谢的能力为基础。在体能状况未完备之前投入 AT训练，无法产生你期待的结果:更快的马拉松成绩。
SHOULD YOU EAT AND RUN? 该不该进食后跑步?
It is best to start an exercise session with stable, fasting blood glucose levels and higher blood fat levels. Glucose is a powerful regulator of fat metabolism. The higher the glucose content of the blood, the lower the fat metabolism. High blood glucose levels are generated from dietary carbohydrates.
开始运动前的最佳状态是稳定的低血糖和高血脂。血液中葡萄糖的高低对脂肪的代谢有很强的调整作用。高血糖会抑制脂肪的代谢，而高 血糖则来自饮食中的醣类摄取。
This effect is associated with insulin. High blood glucose stimulates the hormone insulin to be released from the pancreas. Insulin is a storage and growth hormone. Its main job is to reduce blood glucose but it also acts to store fat and protein. In the process, insulin directly blocks removal of fat from fat deposits. These deposits are an important source of fat for exercising muscle. Insulin also reduces fat burning within the muscle. Therefore, increased insulin is considered to be antagonistic to fat combustion during exercise.
这种机转与胰岛素有关。高血糖刺激胰脏分泌胰岛素，胰岛素是储存和生长的荷尔蒙，主要功能在降低血糖也会促使脂肪和蛋白质被储存 。在作用过程中，胰岛素阻绝体脂肪的移转，这些体脂肪是运动肌肉中脂肪的主要来源。胰岛素也会减少肌肉中的脂肪燃烧。所以运动中 增加胰岛素被视为在抑制脂肪燃烧。
In an interesting piece of research, investigators at the University of Limburg in the Netherlands and at the University of Texas collaborated to determine whether high blood glucose and high insulin levels reduce the amount of fat burned during moderate-level exercise. A group of endurance-trained men cycled for 40 minutes at an aerobic 50 percent of maximum after an overnight fast. On another day, they ingested a drink containing 100 grams of glucose at 60 minutes before and then again at 10 minutes prior to the exercise test. This is a carbohydrate equivalent of drinking one and one-half liters of Gatorade an hour before a race and again 10 minutes before the start. While this may not mimic real-life situations, what the researchers found was telling. Fat metabolism was substantially reduced for the full 40 minutes of the exercise after the carbohydrate load.
研究中有趣的部份是，荷兰Limburg 大学和德州大学的研究者们共同研究测量于稳定程度的运动中，高血糖和高胰岛素是否减少脂肪的燃烧量。一群受过耐力训练的男性受测 者在经过整夜禁食后用50%最高心跳的有氧强度骑40分钟自行车。改天同一组人在运动测试前60分钟摄取含100克葡萄糖的饮料，10分钟前再喝一次，这样的醣类摄取量相当于在比赛前60和10分钟前各喝1.5公升的开特力运动饮料。这也许并非仿效真实情境，此研究说明在摄取醣类后的整整40分钟运动中脂肪的代谢实质地减少。
While most people would not eat that much carbohydrate before a run, it is common for people to eat a sports bar, bagel, or banana in the hour prior to training. Try to avoid eating for at least two hours before a run.
当然多数人不会跑步前吃那么多的碳水化合物，可是在一小时前吃点止饥的食物或香蕉却很平常。请设法避免在跑前2小时内进食。
It takes as little as 20 grams of ingested carbohydrate to raise insulin and reduce fat as fuel. If you have nutrition awareness or read the nutrition labels on foods, you will know that a couple of slices of bread, a banana, a sports bar, or a soda each delivers more than 20 grams of carbohydrate.
只要摄取少少地20 克的醣类就能提高胰岛素和减少脂肪提供能量。若你有营养概念或看看食物上的营养成份标示，你会了解两片土司，一根香蕉，运动能量 棒或汽水，任何一样都供应超过20克的醣类。
Fasting increases blood fat levels. Running after your overnight fast will increase fat burning. A cup of coffee beforehand may boost it even higher. Once exercise has started, eating carbohydrates does not generate a substantive insulin response. If you are starting a long run lasting two hours or more on an empty stomach, you may want to eat a sports gel or bar after 20 to 30 minutes throughout the run. Otherwise you will be faced with the nausea and fatigue of low blood sugar and have a poor training session. If you tend toward hypoglycemia when you get up in the morning, you may want to eat something in the minutes immediately before you head out the door. It takes 30 minutes for insulin levels to peak.
禁食提高血脂浓度，早晨空腹跑步会增加脂肪燃烧。事前一杯咖啡效果更好。 一旦开始运动后进食就不会引起胰岛素的反应。假如你空着肚子进行2小时以上的长跑，你最好在20~30 分钟后补充能量包或能量棒来撑完全程，否则你将面临因低血糖而反胃或虚脱，并且训练无效。如果你有起床时低血糖的倾向，必须马上 吃点东西才能出门，记得胰岛素的浓度要30分钟达到顶点。
However, before a long race or run you will have more endurance and perform better if you eat a meal containing carbohydrate two to three hours before. Early in the morning, your liver glycogen stores, which supply blood glucose, have been depleted by the overnight fast. The brain and nervous system rely on blood glucose for energy. If you start a marathon without replenishing these stores, you will bonk. The two-hour time interval is sufficient to reduce blood glucose levels back to normal and restore fat metabolism.
无论如何，在长距离比赛或训练前2~3小时摄取高醣的饮食必能提高耐力和体能状态。在清晨时，肝脏中的肝醣存量(供给血液中葡萄糖的来源)被终夜禁食所耗尽，大脑和神经系统仰赖血糖作为能量。假如没有补充存量去跑马拉松，你会撞墙。2小时进食间隔己足够让血糖浓度降低至正常标准和恢复脂肪的新陈代谢。
WHICH DIET IS BETTER: HIGH FAT OR HIGH CARBOHYDRATE? 吃什么才补:高脂或高醣?
There has been considerable research in the past decade on the effect of diet composition on endurance. Prior to now, endurance athletes usually followed a high-carbohydrate diet with the rationale that enhanced glycogen stores are known to fuel superior training and marathon race performances.
过去十年己有很多研究探讨饮食控制在提升耐力方面的效果。截至今日耐力型的选手通常遵循增加肝醣的存量可以提升训练和比赛时体能 的理论而采用高醣饮食。
Most sports nutritionists recommend a diet that supplies 6 to 8 grams of carbohydrates per kilogram of body weight. These levels of dietary carbohydrate can easily reach 400 to 600 grams per day. This adds up to 1,600 to 2,400 calories of carbohydrate per day. This type of diet doesn't leave room for adequate amounts of fat or protein.
大多数的运动营养师推荐的餐饮每公斤的体重应摄取6~8克的碳水化合物。如此含醣比例的饮食可轻易达到每日400~600克的醣摄取量，并提供每日1600~2400卡得自醣类的热量。这种饮食调配没有足够的空间容纳适量且必须的脂肪和蛋白质。
The downside of a high-carbohydrate diet, especially a diet loaded with sugar, is reduced fat metabolism and fatigue. This is largely due to chronically stimulated insulin levels. The effects of insulin can last up to eight hours, especially after a big dose of carbohydrates, such as you might get from a big plate of spaghetti and rolls followed by a bowl of sorbet.
高醣饮食的负面影响是减少脂肪的代谢和造成疲劳，特别是吃太多甜食。主因是长期地刺激胰岛素的浓度。胰岛素的效应会延长至8小时，尤其在吃下大量醣类后，好比吃了一大盘的义大利面后再吃一碗果冻。
Initially, studies found that high-fat diets, where fats supply 60 percent or more of the calories, showed promise as a means to better endurance. Fat burning is increased on high-fat diets, even at rest. Exercise tests showed higher endurance in subjects who had been eating high-fat diets in comparison with high-carbohydrate diets.
研究初期发现脂肪供给热量超过60% 以上的高脂饮食确实是增加耐力的辨法。高脂饮食促进脂肪燃烧，即使在休息状态亦然。运动测试显示高脂饮食比高醣饮食有较好的耐力 表现。
At issue, however, was the intensity of exercise used for the tests. High-fat diets improved endurance at relatively low-intensity levels. When the intensity was increased to mirror race situations, the advantage disappeared. The higher- intensity exercise required more carbohydrate, and the subjects simply lacked adequate glycogen to continue for extended periods. The lesson is that you can reduce your reliance on carbohydrate, but you can't eliminate it.
值得争议的是测试的运动强度。高脂饮食仅能提高耐力在低强度的运动中，当运动强度提高到真实比赛的状态时，上述的优势便丧失了。 高强度的运动需要更多的醣类，跑者很容易缺少适量的肝醣持续比赛。由此例我们学到，可以减低对醣类的依赖但不能省略。
We now know that both high-carbohydrate and high-fat diets cause fatigue and poor performances. The best diet is probably somewhere in between: one that supplies enough fat to stimulate fat metabolism and maintain production of testosterone and estrogen and also supplies enough carbohydrate to keep the brain and nervous system happy and the glycogen stores filled. Many sports scientists are recommending a basic diet that supplies 50 percent carbohydrate, 30 percent fat, and 20 percent protein, with additional carbohydrates after hard or long-duration training.
现在我们了解高醣和高脂饮食都会造成体能下降，那最佳的营养调配应该是介于之间: 有足够的脂肪刺激体脂肪的代谢和维持制造睪固酮和动情素，也供给足够的碳水化合物使大脑和神经系统保持愉悦及肝醣的储存。许多运 动科学家建议基本的饮食供应50%醣类30%脂肪20%蛋白质，在艰苦的耐力训练后另外增加醣的比例。
MORE QUESTIONS 更多的问题
There are still many unanswered questions regarding nutrition and endurance sports performance. Before a marathon or longer race, will fat loading in combination with glycogen loading boost performance? After hard or long training, should you also concentrate on replenishment of fat stores in the muscles? What type of fat, saturated or unsaturated, is burned for fuel? Will eating fat during races that last four hours or more benefit performance outcomes?
还有很多关于营养和耐力运动的问题无法解答。在马拉松或长程比赛前，同时累积脂肪和肝醣会不会有更好的体能?经过重度操练后该不该刻意恢复肌肉中的脂肪存量?那种脂肪(饱和或不饱和)被燃烧来供给能量?在比赛中摄取脂肪能不能维持4小时或更久的体能表现?
What profile of fats in the basic diet is best for an athlete? The skeletal muscle membrane is made of fat. The composition of this membrane directly reflects the profile of fats in the diet. A diet high in saturated fats will generate a more solid, less fluid membrane. A membrane that incorporates more unsaturated fats is more fluid, allowing a more efficient flux of oxygen, water, fat, and glucose. New theories hold that these membranes are more leaky and require more energy to maintain. Conceivably then, a diet too high in either saturated or unsaturated fats could be detrimental to endurance performance.
在一般饮食中何种形式的脂肪最有利于运动员? 骨胳肌薄膜是由脂肪形成的，其组合的状态直接反映出饮食中摄取脂肪的种类。饱和脂肪多的饮食会产生固态多于液态的薄膜。薄膜包含 较多的不饱和脂肪时流动性好，容许更有效率地氧气、水、脂肪和葡萄糖的转换。新的理论支持这些薄膜应该更具渗透性并需要更多能量 来维护。可以想象的是过度偏重摄取饱和或不饱和脂肪的饮食必将损害持久力。
While there are new training methods being developed to enhance marathon performance, you will find substantial success with theories that are now 40 years old. In contrast, the field of sports nutrition research is currently experiencing great strides. In the early 1990s, the accepted dogma of a high-carbohydrate diet came under fire and was dismantled. Until we have more definitive information, it is wise to follow a moderate, low-sugar, common-sense diet with high nutritional quality.
当有许多加强马拉松实力的新训练方法产生，你会发现这套40年前的理论许多实质的成就。相对的，运动营养学的研究目前也有大幅的进展。90年代初期所信奉高醣饮食的教条被打破，直至更多的证据确认，采用适量、低糖、正常饮食来提供高素质的营养补给才是明智的选择。
With a training and nutrition regimen that coerces you to tap into your fat supplies, you can teach your body to use more fat during your migration through the marathon, and beyond.
利用训练和营养调整的方法强制自已开发体脂肪的供应，让身体运用更多的脂肪来完成甚至超越马拉松吧!
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