Body Weight effect on Race Time

Great idea if you truly care more about race performance than gym performance. 25lbs of pure fat would probably get you down to 19 minutes or so. Not sure about some muscle loss as well but I'd imagine it would at least get you down under 20, especially if it's those lower body muscles life calves that you let atrophy.

With that college PR you'll certainly be able to break 20 once you start getting consistent training under your belt. Dieting clean is big, but honestly if you just start to increase your mileage (especially long run) in a responsible manner, I bet you'll shed a bit of weight and your times will go down. Good luck to you!

Common rule of thumb is 2 seconds per pound per mile. But I'm sure at some point you find some diminishing returns.

You may or may not have been over weight in college. While in college, you were trading on your 200m/400m/800m/1500m speed. Many will say body fat measured at grocery stores is not accurate. It's close enough. Concentrate getting under 10% body fat. It will take discipline. What you put in your mouth will be more important than exercise.

HazBeen,

With your impressive background and 14:39/5K you have good potential to quickly improve to under 17/5K. 41 y.o. is a very nice age!

When I returned back to running at the age of 60 I ran 5K at 22:45 weighing 73 kg (160 lbs), while my "combat" weight at 20+ was 123-125 (I am 5'6 1/2"). Exactly a year later I dropped 8 kg (became 143 lbs) and made it under 20 (19:56). One more year later the weight reduced to 61.5 kg (135 lbs) resulting in 5K/18:53.

Best of luck to you!

Update, as I am trying to keep myself motivated. Weight is down to 185-190 depending on what time of day and how much of my kids candy I eat.

I did a five-mile race a month ago as a tempo run and managed 7:02 pace without working too hard.

And then my legs got angry. Knee pain on left side and plantar fasciitis on right. Blah. I've had to cross-train for a couple weeks while I work on the plantar fasciitis. It seems to be getting better, and I am hoping to do a 5k on July 4th and see if I am down around 20 minutes.

Still shooting to get down to around 175lbs. by end of year. We'll see...

Focus on the running and figure out how to safely ramp up your mileage without getting hurt. Be somewhat mindful of what you eat, but don't focus on weight. Weight will come off over time.

Other way around at 41. Make losing weight gradually a priority, while very slowly building up to regular running.

Starting at 39, it took me a few years to drop from 195 to ~165. At 44, it took me something like 4-6 months of embarrassingly slow, gradual work to build back to serious running (and also drop to 150 pounds) while avoiding the debilitating knee injuries that had derailed earlier comeback attempts. After that, it got to be a lot more fun.

I think there was an old study that showed that participants got 2.4s per km slower for each additional kg that they were carrying. I think the added weight was in the form of weighted vests, so there may be a little discrepancy when translating to the real world, as the weight is distributed different among individuals. But this study show similar results to another method which is dividing your current VDOT score by the percentage of body weight that you plan to lose.

But you have to keep in mind that it only works if you actually have excess body fat to lose, and even still, when you lose weight,you don't lose only fat and studies shows that around 25% of the weight that you lose come from muscle mass loss.

So, my humble advice would be to focus on body fat percentage intead of weight and doing weight training alongside your running to prevent excessive muscle loss, and of course, consuming enough proteins.

On the matter of protein consumption, recent studies shows that east african distance runners consume about 75% of their calories in the form of carbs, 12-13% fats, and 12-13% proteins, and that they actually lose some weight, that is, they go into caloric deficits as goal competitions aproaches.

12% reduction in weight with all else equal you'd prob have run about 7-8% faster

21:00 turns into 19:30ish