I have the same experience going on 2 years ago. Went from 245 down to 218-220. I gained at least two gears higher on the hills and am faster on the flats also. Now if I could only get down past 200lbs, then the difference will be profound. Here's to hoping... As Mr Lemond said, "It doesn't get easier, you just get faster."

Congratulations with the weight loss and fitness.

The problem is you need the exercise to prevent muscle loss.
But, if you compare your fitness levels before and after dieting + exercise, more than one thing has changed.

I'm also down about 15-20 pounds this summer, with a goal of an additional 5 to 10 pounds. Then hopefully controlling the eventual bounce-back to perhaps 5 pounds or so.

However, I consider fitness changes with just spending more time on the road.

I do notice quicker recovery after climbing certain hills, but I attribute that to training.
I also hit my personal all-time high for flat all-out speed (short, as well as a 10 mile ride). But, I hadn't made those exact efforts earlier either.

If you run a Powertap. 200W at the rear wheel for rider A is about the same as 200W at the rear wheel for rider B.

Getting that power to the rear wheel may vary considerably from rider to rider. For one rider, it may be an all-out sprint, for the next, absolutely coasting.

Overall efficiency???? One rider might be pushed over the anaerobic threshold at 200W, and can't maintain it, while the other rider is well in the aerobic exercise zone, and can maintain it for hours. Changes in Oxygen absorption and uptake?

I think what he meant was more like losing weight would make it easier and less taxing to produce 200 watts. Like at 220 lbs it might take 250 kCal to make 200w but at 200 lbs it would only take 230 kCal to make 200w. Maybe that's not what he meant, but that's how I took it because how else would you measure the efficiency of producing 200w? (If it's going to improve with weight loss, that improvement has to mean something, it has to at least theoretically be measurable.)

Great thread and good post.

Oh oh. I have an important question that will destroy some people's dreams. Does the graph and discussion above also extend to bike weight not just rider weight?

If so, what does the graph look like for dropping 1kg (2.2 pounds) of your bike?

My understanding is that it will only minimally (barely) improve speed on the flats but will help when climbing.

Do you go fishing, if so, you've opened a can of worms and should hang out for some free bait.

First of all, as I mentioned earlier, this is simply a rough approximation of net effect of weight change. So bike or body, it's all the same thing.

OTOH there's plenty of opinions, and some science, on the differences between weight changes on the body, bike or wheels. Lot's of debate on the subject, comparable to a chain lube debate, and few meaningful answers. There is a general consensus, that weight reduction at the rim counts double (supported by good science) for purposes of acceleration, but not for climbing or constant speed riding. There's also some (not as much) consensus that weight on the bike counts a bit more than on the body, reflecting the fact that riders move the bike around under them (I buy into this, but consider it to be subtle).

Also, think about what happens when climbing steep grades at low speed and cadence. The bike undergoes decent size speed changes with each pedal stroke, so the effects of weight are slightly greater than at constant speed. Then there's "feel". Lighter bikes feel lighter and snappier, that may produce a placebo effect that helps riders ride as if it actually made a difference. IMO- for whatever reason, losing 5#s off a bike feels like a bigger difference than losing 5#s off your body.

Throw all of this into the hopper, and draw your own conclusions, and maybe tweak the overall graph a bit, but it's just another set of small variables so don't assign it more value than it deserves.

The rule of thumb here, and in similar discussions, is that the science can get you to the right city, and even (maybe) to the right ball park, but if you think it can get you any closer than that you're kidding yourself.

No problem here. I thought I was exercising.

My rides are custom for my soma-type and personality. Every one of those 3 rides are intense. The weekend ride will max at 70 miles with hills. I am not a distance rider any more than I was a distance runner in track.

Very well said. If one jumps from one study to another and never finding what works they very well could be wasting efforts attaining personal goals.

Exactly, I agree.

Certainly there is something to this, but it can be difficult to separate all the many variables. For example, me + road bike + all the cr@p I carry when I ride is probably 220-225 lbs., whereas me + mountain bike + all the cr@p that I carry is probably 250 lbs. So yes, it is harder to climb with the mountain bike, but part of that comes from riding on dirt, part from the big fat knobbies that I have on that bike, and so on.

As an aside, a friend told me about this quasi-experiment (but I never saw it in print anywhere) where weight (maybe lead in the seat tube) was added to a bike without the knowledge of the rider, and the rider was asked to indicate at what point the extra weight was noticeable. Supposedly professionals could identify changes on the order of a few ounces, whereas freds like myself could only identify changes on the order of a few pounds. So if that is true, there is also a great deal of subjectivity when it comes to perceived effort (at least for freds like me).

I lost 50 lbs in the last 6 months. I was diagnosed with diabetes and went on a low carb, high fat diet. I'm 6'4" and went from 235 to 185 and I noticed a huge difference with climbing and overall speed plus endurance is better. I'm still not very fast, but now I can't imagine riding 50 lbs heavier. Now if I can just get a lighter bike...but that's another thread.

Which is exactly why I speak about finding the city and only maybe the ballpark. There are also differences that are simply about what you're used to and what feels different. Folks like to debate the details, but I don't like to fret about any small stuff who's variance is less than the margin of error in the big stuff. It's a bike, you turn the pedals and it goes. After that it's pretty much nonsense for all but the most serious riders.