Welcome to the quick and dirty tips to slim down and shape up. My name is Brock Armstrong,

and I'm the Get Fit Guy. Breaking the two-hour marathon has been a hot topic in the running community

for quite a while now, but with the recent highly publicized Nike attempt, it's become even

more intensely debated than ever. The authors of

how biomechanical improvements in running economy could break the two-hour marathon barrier

looked at how, among other things, shaving 100 grams off the weight of a runner's shoe

could contribute to a sub-two-hour marathon.

That idea got a lot of runners thinking.

If 100 grams is important enough that Nike developed new shoes for the job,

how much could losing a few pounds off my actual body weight help me break my own speed records?

When considering this, the first question to ask is,

can you lose weight without sacrificing performance? The balance between weight loss and maintaining

performance comes with a mixed message. Yes, you can lose weight while training for a race. No,

it's not an easy thing to do. But we are talking

about people who run 42.2 kilometers or 26.2 miles for fun, so let's not sell them short. What does

the science say? A new study called the effect of acute body mass reduction on metabolism and endurance

running performance took a fresh look at this idea.

During the past 40 years, the majority of studies have been centered mainly on the effect

of adding external load to the energy cost of walking and running.

But in this study, they took 11 trained club

runners, eight male and three female, and had them participate in a series of four maximal trials

that were four to six days apart. During the first trial, the subjects completed an exhaustive

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