Does body fat play into running?

Yes body fat does play a role. Think about it. Someone with a body fat of 30% vs 6%. Who do you think will win a race. 6% is probably the lowest you'd wanna go. Anything lower is risking unhealthy habits.

Fat is an efficient source of energy -- that's why the body stores it for later.

However, too much fat requires more work (i.e. more energy) to move more mass the same distance.

Hard to say what the average is for a good runner.

Men can become leaner than women (sorry ladies).

Yes body fat does play a role. Think about it. Someone with a body fat of 30% vs 6%. Who do you think will win a race. 6% is probably the lowest you'd wanna go. Anything lower is risking unhealthy habits.

I know a 40 year old man who weighs 184 lbs. at an accurately measured 3.4% body fat, and he is in perfect health. He won the genetic lottery. The average man is literally incapable of going that low even with a starvation diet.

4-8% body fat is the range suggested by Coe / Martin for male competitive runners. 8% is fairly lean; 4% is very lean.

I think, for women, they say 8-13% is good.

I've experienced about a minute per pound of excess body fat in the marathon. I would say it's about 8 seconds per pound in the 10K. These are just general guidelines. Try putting on just a 10 pound weighted vest and running in that for a few miles.

DangerZone wrote:

I was curious as to whether body fat has any role in running. It seems like runners are incredibly lean.

In a sea of stupid things uttered on this message board these to sentences stand out as some of the most stupid. Congrats- that's a difficult task.

ANY role??!! Seriously? You don't know just by looking at runners, or thinking about the activity that body fat would have ANY role at all? I guess you base this question on the fact that there are some Oly marathon champs that look like sumo wrestlers and some gold medalist that are Kenyan thin? Yeah there is just a HUGE diversity in the body type of WC runners.

I guess whoever said "there is not such thing as a stupid question" hadn't met you.

These answers were exactly what I was looking for:

Safe range 4% - 8%

1 minute per pound in the marathon

10 seconds per pound in the 10k

I am 5.7% body fat at the moment and I was not sure how I compared to WC runners. My guess is that Olympic athletes are closer to the 4% mark for body fat. Does that sound right?

Also, I was wondering, are any of those home body fat scales accurate?

marijuologist wrote:

Yes body fat does play a role. Think about it. Someone with a body fat of 30% vs 6%. Who do you think will win a race. 6% is probably the lowest you'd wanna go. Anything lower is risking unhealthy habits.

I know a 40 year old man who weighs 184 lbs. at an accurately measured 3.4% body fat, and he is in perfect health. He won the genetic lottery. The average man is literally incapable of going that low even with a starvation diet.

Is that guy really ripped or something?

I don't think you can put "accurately measured" and "3.4%" in the same sentence.

If it was done using a 7 site skin fold by someone who knows what they are doing then you can believe it. Any other way, save for underwater weighing or bod pod, and I'd be suspect.

Alan

Lower body fat means more lean muscle to generate power/force. However, because muscle weighs more than fat, you're not going to see a muscled-up weight lifter out-running someone who's lighter and has less weight to carry. Comparing a lean woman to a lean man, the lean man will likely have more lean muscle to generate more power/force to go faster (along with other gender differences favoring men: http://home.hia.no/~stephens/gender.htm).

DangerZone wrote:

These answers were exactly what I was looking for:

Safe range 4% - 8%

1 minute per pound in the marathon

10 seconds per pound in the 10k

I am 5.7% body fat at the moment and I was not sure how I compared to WC runners. My guess is that Olympic athletes are closer to the 4% mark for body fat. Does that sound right?

Also, I was wondering, are any of those home body fat scales accurate?

I agree with the time improvements, but only if you have made similar improvements in training times.

But the low bodyfat measurements that are often quoted are highly suspect. People who say they have 3% are probably 6%

So I doubt your 5.7% very much, if you were really that lean, you would have less bodyfat than many of the top distance runners.

Not necessarily. I\'ve been off running for a few months and during that time actually decided to change some stuff about my diet so whilst not \"healthy\" it\'s certainly a lot better than it was (e.g. not eating at KFC/burger king/mcdonalds) anymore. Result is that I\'ve lost over half a stone in weight. Just started running again last week and it\'s like I didn\'t stop running at all-or maybe even faster! Absolutely flying.

Obviously in the extremes it\'s not going to make a huge deal but losing excess body fat helps hugely when done correctly.

Not sure what your point is there Bryn?

I guess the only way to really know is to get a hydrostatic test.

All my personal bests were run when I was at my leanest. Not eating disorder lean, but below an average person's body fat percentage. I had to to be very conscious about trying to trim the extra fat. The optimal percentages are surely below what is an average ideal body fat percentage.

Fat doesnt fly. Most would improve if they lost weight, and everything else stayed the same. It's a cruel fact of distance running.

I have learned to run fast with more weight, but it is definitely harder(I am older too which slows you down as well).

ive heard people talk about percentage body fat in relation to Vo2 max. The lower your body fat the the better your Vo2 max can be (was explained to me by a coach). something in relation to using too much oxygen to move a heavier body.

The issues with very low body fat affect training more than one off performance - very low body fat over a period of training can compromise the immune system (leading to loss of training time) and lead to significantly more serious joint damage that might otherwise occur due to taining mileage.

On a related not, does body fat affect your ability to pitch a baseball? Doesn't seem like it.

You don't need a coach to explain it. V02 max is a per kilogram measure. Think of something you buy per pound at the store, such as meat. If it's $4.99 per pound, and you buy a larger package, it costs more, as the price is multiplied per pound. Since Vo2 max is divided by kilograms, if you lose a kilogram of weight (or fat as your wish) then your Vo2 max is higher. It's a measure of the volume of oxygen you utilize per kilogram of your weight. Keep the same athletic fitness level, lungs, oxygen carrying, distribution and utilization and lose some weight and the Vo2 max figure goes up, because you are dividing by a smaller number of kilograms to get your Vo2 max.