锻炼身体前,该吃些什么?

kingburg

By STEFAN ASCHAN
Sept. 12, 2007

\"What should I eat?\"

It's a common question that nearly everyone deals with on a day-to-day basis. For those adhering to a workout program, however, this simple question gains added importance

Believe it or not, it's a source of stress for many who hope to maximize their workout gains. While some of us choose to gobble down a carefully chosen assortment of foods right before stepping onto a treadmill, the rest of us do the opposite — we don't eat anything before exercising.

So who is right and who is wrong?

Some of this confusion can be cleared up by first understanding how our body uses food for fuel. At the heart of the matter is a molecule called adenosine triphosphate (ATP), which serves as a direct source of energy for doing cellular work in any kind of living cell.

Here's the catch: The energy from food needs to be processed in order for it to reach this usable form. This occurs slowly, mainly because of the necessary chemical reactions that need to occur in order to convert the molecules in food into ATP molecules.

So what is best to eat right before a workout? The answer to this question: nothing.

Why, you ask? Because anything you shovel down before a workout will be too late to have an impact on the levels of stored ATP needed for your working muscles.

Thus, the question we should really be asking ourselves is, \"What should I be eating hours before my workout in order to supply my body with the best energy to do its job?\"

No Substitute for Preparation
Preparation is the real answer. It is best to eat foods that give you the energy required for your workout.

This is not just muscle-building protein, mind you. It also means carbohydrates and foods that contain fats, minerals and vitamins. And yes, you should eat meals that have all of these nutrients together.

All right, I hear you thinking: Carbohydrates? Yes, you need carbs; carbohydrates are the body's primarily energy source. When you don't provide your body with good carbohydrates, you don't give your body its necessary fuel and you won't perform at your optimum.

But keep in mind that these carbs should be the unprocessed kinds that still have all the nutrients inside. Processed carbohydrates, such as white rice, white flour and your run-of-the-mill pasta, are usually stripped of their most beneficial nutrients.

When you eat processed foods (in other words, processed carbohydrates), your body does not receive the minerals and vitamins required to metabolize and properly use food for fuel. Minerals and vitamins are among the key factors in our bodies' necessary chemical reactions. If we don't have them, nothing works. Providing ourselves with foods that give us required nutrients is necessary to receive the energy throughout your workout, as well as throughout your day.

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Timing Is Everything
Again, a reminder: No matter how healthy the food, you'd do well not to eat right before the workout — unless, of course, you savor the experience of throwing up while exercising.

When you exercise, your blood will flood into your working muscles, leaving less energy for digestion. Thus, when you eat before a workout, your body has no other choice then to deal with the digestive demand, and it has to put its energy into digesting the food. That is the issue we have here.

So how long should we refrain from eating before working out? Granted, much depends on the individual and what kind of food they eat. But in my experience, clients did best when they ate a small meal two to three hours before working out.

But even two to three hours can be too short if you eat fried, fatty foods; they might greet you during your workout program in the form of burping, heartburn and diarrhea.

Yes, food choice is very important, too. The best advice is to try to eat light and healthy, such as a plate of greens or fruits. And if you are simply starving before a workout, fruits are the best way to go; they generally stay no longer then 30 minutes in the digestive tract.

If you're thinking of a larger, balanced meal, allow five to six hours before working out. This will give your body enough time to convert the food molecules into ready-to-use molecules for the energy you'll require.

The intensity of a workout is another factor to consider. Light foods for intense workouts.

And then there is the time of day during which you choose to work out. Are you an early riser? When you work out in the morning (yes, some of us do get up and start moving at 6 a.m.), it is best to just drink water to hydrate your body after a long night's sleep. Don't forget, you most likely ate dinner 8 hours before you woke up, so you should have enough energy to get you going.

Keeping Yourself Hydrated
Just as important as proper energy from the foods you eat is proper hydration from the water and drinks you consume before and during your workout.

Sports drinks? Ah, OK, I have not forgotten about them. Sports drinks can be great during the workout to replace your electrolytes while working out. Electrolytes such as potassium, magnesium, calcium and sodium allow your body to fend off fatigue and function properly during exercise.

But one thing we all have to keep in mind is to watch out for the sugar content in sports drinks, often in the form of high fructose corn syrup. Processed sugars like corn syrup can spike your energy levels, only to set them up for a fall after about 20 to 30 minutes. This is something you will probably want to avoid during exercise, as it's best to keep your blood sugar levels even throughout a workout.

In short, the calories we get from food and drinks are workout fuel; you shouldn't be afraid of them. Just keep in mind that food should be eaten hours before you tie up those cross trainers, and be mindful of sugary beverages.

Perhaps the best advice is to be sure to pay attention to when and how much you eat before your workouts, particularly when it comes to how these habits affect your ability to exercise. This is the best way for individuals to determine what feels right for them.

Nevertheless, keep in mind that your body needs proper fuel to function at its peak level.


来自丁香园的译文：http://www.dxy.cn/bbs/post/view? ... amp;tpg=1&age=0

“我该吃点啥呢？” 这是个在日常生活中几乎人人都会面对的共性问题。然而，对于那些长期坚持锻炼的人来说，这一简单的问题就显得更加重要。不管你信不信，对于那些想加强健身效果的人们来讲，这是他们压力的一个根源。
我们中的一些人会在上跑步机运动之前去狼吞虎咽一些精心选择的配餐，而其余的一些人则做法相反----在运动前什么也不吃。那么，谁对，谁错呢？首先要明白我们的机体是怎样利用食物来提供能量的，这样这个困惑就可消除一些了。问题的核心是一种被称为三磷酸腺苷（ATP）的分子，它可以为任何类型活体细胞的细胞生命活动直接供能。于是我们知道：食物中的能量需要经过处理以使其成为这种可以利用的形式。这个过程是缓慢的，主要是因为把食物中的分子转化为ATP分子需要进行一些必要的化学反应。那么，在运动之前最好吃什么呢？答案是：什么都不吃。你会问，为什么？因为在运动之前摄入的食物根本来不及对肌肉运动所需的储备ATP的水平有所影响。因此，我们真正应该问自己的问题是，“在锻炼的数小时前我应该吃些什么才能使机体能够精力充沛地应对呢？
非特制食品莫属
特制食品是最佳的答案。最好吃一些能够提供给你锻炼所需能量的食物。提醒你一下，这不仅仅是指肌肉构建蛋白。还包括碳水化合物和含有脂肪，矿物质及维他命的食物。当然，你应该吃同时含有所有这些营养成分的膳食。好吧，我知道你在想：包括碳水化合物？是的，你需要碳水化合物；碳水化合物是机体主要的能量来源。当你没有为机体提供充足的碳水化合物，你也就没有为机体提供必要的能量，因此你也就不会呈现出自己的最佳状态。但需要牢记的是，这些碳水化合物应该是仍然含有全部营养成分的未加工的形式。加工过的碳水化合物，例如精白米，白面和普通的生面团，通常都除去了最有益的营养成分。当你吃加工的食物（换言之，就是加工的碳水化合物），你的机体没有获得新陈代谢所需的矿物质和维他命，无法合理地利用食物供能。矿物质和维他命属于机体必需的化学反应的关键因子。如果我们没有它们，什么都干不了。供给自己能够提供必需营养的食物，对于获得锻炼全过程所需能量，甚至一天所需的能量是很有必要的。
再次提醒：无论食物多么有益健康，你最好不要恰在锻炼之前吃---当然，除非你想要体验一下锻炼时呕吐的经历。
当你锻炼的时候，你的血液将会流入正运动的肌肉中，而留较少的能量用来消化。因此，当你锻炼前吃饭的话，你的机体不得不应付消化需求，把它的能量用来消化食物。那就是我们的提出的问题之所在。那么，在锻炼之前我们应该禁食多久呢？我们得承认，这更多的取决于个人以及吃的食物的种类。但就我个人的经验而言，在锻炼前的2-3小时少量进餐的效果是最佳的。但如果你吃是油炸的，含脂肪的食品的话，即使提前2-3小时也是不够的；这些油炸食物可能导致你在锻炼的过程中出现嗳气，烧心和腹泻。
当然，食物的选择也非常重要。最好的建议就是试图去吃易消化（清淡）和健康的食物，例如一盘蔬菜或水果。如果你在锻炼前正在节食的话，那么吃一些水果是最佳办法；它们通常在消化道停留的时间不会超过30分钟。如果你在考虑一顿丰盛的均衡膳食，那么应该在锻炼前5-6小时享用。这将为你的机体将食物分子转化为供给机体所需能量的随时可利用的分子提供足够的时间。
锻炼的强度是需要考虑的另一因素。吃易消化（清淡）的食物来应对高强度的锻炼。还要考虑的就是一天中你选择去锻炼的时间。你是一个早起的人吗？当你在早上锻炼的时候（当然，一些人在早6点起床活动），最好只是喝一些水来以使自己在长夜睡眠之后补充水分。不要忘记，你最可能是在睡醒之前8小时吃晚饭，因此你应该有足够的能量来支配。
保持机体水分充足通过饮水来提供水分以补充锻炼之前和锻炼之中消耗的水分，这一点与摄入食物提供的适当的能量同等重要。运动型饮料？哦，是这样，我还没有忘记它们。运动型饮料能够在锻炼过程中，当电解质代尽的时候予以补充。电解质，例如钾，镁，钙，钠能够抗疲劳，在锻炼中起到适当的功能。但我们不得不牢记一件事：小心运动型饮料的含糖量，经常是以高果糖玉米糖浆的形式存在。象玉米糖浆这种加工过的糖，能够在摄入大约20到30分钟后下调你的能量水平。这是你在锻炼过程中需要避免的事情，最好在整个锻炼期间保持住你的血糖水平。简言之，我们从饮食中获得的能量是锻炼所需能量；你不应该畏惧它们。只要记得，食物需要在你健身前的数小时摄入，并且要留意含糖饮料。
可能最佳的建议是：务必留意在锻炼前应该何时吃以及吃多少，特别是当考虑到这些习惯是如何影响你的锻炼能力的时候。这是每个人用来确定什么习惯适合他们的最佳的方法。然而，需要牢记：身体需要适宜的能量来维持最佳的生理功能。