How about the speed in moving the weight and... a headwind?

If you are among those of us who have adopted or are adopting a lower carb regimen it does take some time for the body to switch gears and for some it requires some calorie restriction and for others it is just a matter of reducing carbs.

My wife lost a considerable amount of weight by reducing her carbs intake but not reducing her total caloric intake and her energy levels are pretty much through the roof. She has also maintained the weight loss and her physicals show some remarkably good numbers.

I keep my carb intake below 100 grams per day and this keeps me lean and my weight stable... and my endurance and energy on the bike is excellent.

Protein should be matched to maintain your lean muscle weight; excess protein will convert to glucose and bump your blood sugars and this is where a lot of folks have problems, not understanding the process that is gluconeogenesis.

Those would be the portion without (or disregarding) the climb, the 33 calories per mile estimate for example. The energy added by the climb is m*g*h. This sort of thing tends to get over-thought. You can just add energies, as long as you keep them straight.

Here's how I see it. Gravity is a "conservative force" meaning it takes the same energy from point A to point B no matter how you get there. Up and down a hill, or around it, the same energy. But we all know that it's harder going up the hill, and that we burn more energy - just look at a bunch of strava rides rides if you don't believe it. Looking at it logically and extracting the different parts may seem like simplifying, but it's just getting down to what's really happening.

Unless it's really steep you're probably pedaling down anyway, using that estimated 33 cal per mile but just going faster. You're using that "flat ride" estimate going up as well. But you are also lifting that weight a certain distance, in addition to riding around. That part is easy compared to everything else: it's just weight times height times gravity. Just add it in.

Wind resistance, speed, what bike you're own, all of that is where the estimate per mile will break down or at least need to be modified individually. But it doesn't much pertain to lifting the weight up the hill.

A flappy vest isn't going to slow you down much on the way up the mountain. Aerodynamics are an important factor at high speed but not as much at low speeds. And anyway air resistance makes you work more for the same speed, which a power meter will capture.

That may be close to true on pavement. Dirt takes a lot more energy.

I've never been very comfortable with rules of thumb and formulas. I prefer to just measure. Even if my measurement is imperfect (like all measurements are), I feel more confident in a reliable, consistent method of evaluating the work I've done.

That may be true for you because you and Rowan are fairly consistent in riding speed and conditions. However conditions will make a difference, and you'd burn more on rough roads than smooth. You also don't factor headwind, and lets face it, 10 miles into a headwind is burns more than the same 10 miles with a tailwind.

Lastly, the work done (fuel burned) isn't linear with speed. Drag is proportional to the square of wind speed (or ground speed in still air), so riding the same distance at twice the speed would mean you're working against 4 times the drag and would be working 4 times harder.

This square of the speed is why motorists are encouraged to drive slower to save fuel, and likewise cyclists riding slower would also save.

But, as I posted earlier, all this pointalism can hide the big picture. It isn't how many calories you eat or burn TODAY, it's the cumulative effect of your net calories in vs. out over time that counts. All this data may provide some guidance, but it doesn't have to be precise to do so. The acid test is net gain or loss of weight over time, and based on that you can make adjustments to the big picture stuff, then check progress next week to see if you're still on track.

Listen to your advisers here. Pick the smallest calculated burn and go with it. Stop wishing you were burning more. There's no point to it. Go for the results you want, which is going to involve going calorie negative, like it or not. The scale tells the truth. If your calorie numbers are correct, the scale number goes down. If they are not, your scale will tell you.

If you want to get your burn up, work on getting the Strava average watts up. I have a SS with date, distance, and average watts. Obviously with increasing distance, average watts go down, but getting them up over the same distance is a good sign. PRs are a good sign. I like to see at least one PR on every ride if I'm actually training and not just piddling on the bike.

It is and it isn't. On a flat ride at relatively constant speed weight barely matters because you're working against the wind rather than gravity. However, when your climbing you're working against gravity and weight counts. At the same time wind counts less because most people climb at lower speed than they cruise on flat ground.

So, weight will matter to a greater or lesser degree depending on the specifics of speed and terrain.

But, I repeat (I promise for the last time) You're standing too close and focused on the small dots that make up the picture. Stand back and look at the big picture and you'll see that it's not about each ride or each meal. It's about the long term intake and output, and the trend, even if there are reversals along the way.

It's like climbing a long grade to a mountain pass. Though you're climbing and end up higher, it doesn't mean that there won't be downhills along the way.

Just to clarify, I am not wishing I was burning more. What I have tried to convey is that although my activities have remained relatively the same and my calorie intake has dropped significantly, I have not lost weight. This is over a 6-8 week period. That's what I don't understand. In the past if I had done this I would have lost some weight.

The discussion of calories burned via cycling is interesting to me only because every website I've ever visited and every book I've ever read and every trainer I've ever spoken to says that calorie burn is affected by a variety of factors and isn't as simple as X number of calories per mile regardless of all the other factors.

Yes, the websites and the information posted here agree that it isn't as simple as a straight line correlation of calories per mile. But that's still a useful benchmark for comparison for the same person doing similar rides in his area.

It's about as useful as the average time you allow for your commute, which can change due to weather, changes in traffic, time of day, or if there's a collision or road closure, and here in NYC whether the President is in town. But you still use the benchmark, because you can't go through lif with a calculator.

As for weight loss or lack thereof, there are various possibilities.

1- you're kidding yourself about how much you're eating.
2- you're trading fat for muscle (you'll know because you're pulling the belt smaller
3- you're holding more water during recovery
4- over time you're becoming a more efficient engine, so burn less fuel for the same speed and distance.

Though I understand that weight loss is your goal, that's only one indicator of what's going on in your body. A better one is measuring lean vs fat which can be done one of a few ways, or you can either be patient and give the current regimen time to work, or cut back another 5-10% on the input side, and/or increase speed and mileage a bit and give it more time.

BTW- a staggering amount of weight can be "hidden" in your legs. The lean muscle mass is dense, plus depending on how you ride the long bone mass can go up slightly. Combine that with the fact that you don't tend to see leg weight, and it's obvious that cycling can make you heavier than you look.

My advice, don't let the scale discourage you, keep it up and measure by how your clothes fit. If you feel stagnated, consult a nutritionist for help balancing the makeup and timing of your diet for more activity.

First, thank you for putting the time and energy into considering my questions. I appreciate that.

1. I'm doing a daily compilation of what I eat and I know for sure that I'm eating significantly less than I had been.
2. I may be trading fat for muscle. I have assumed that at age 70 that would be unlikely but I don't know. My waist is now about 2" smaller. I can now fit into 34 jeans.
3. Have no idea.
4. At age 70 I'm just happy the engine still starts.

Ah. Probably you're becoming a little more efficient as you lose fat and gain muscle and particularly, muscle tone and a more efficient pedaling ability. It's still CICO but you're having to adjust to more correct calorie measurements.

As I and [MENTION=158672]FBinNY[/MENTION] say, measure more than your waist.

So there it is. You're losing waist, if not weight, and unless the fat that used to be around your middle is now around your neck, you're trading waist fat for leg muscle.

BTW- after a while, your legs will have the muscle they need and plateau there, so your lost waist fat will show up on the scale. Until then let your belt be your guide.

We may need a physics check. I believe it takes more energy to move a given object more quickly. Lance Armstrong had to calculate how much energy it would take to raise his body and bike weight to the to finish line at Alp D'Huez but he also had to include how much more energy it would take to be at that line sooner than Jan Ullrich.

I said this earlier in the thread and sprince kind of freaked out, but this bears repeating. It's not (fully explained by) #2. And I mean no offense to Bruce when I say this. As a rule:

If your efforts at weight loss have stalled, "you've accidentally built several pounds of muscle" is never the reason why.

Why?People say it a lot, maybe you're hitting a plateau because you're building muscle, at exactly the same rate as you expect to burn fat. It's a very common myth.

A DEXA scan will reveal all, and is relatively cheap. There's a place nearby that does 3 of them over an 18 month period for $300. I've been making a concerted effort to gain weight (build muscle) for months and I'm considering this.

Yes, I see now. Ignore enough variables and everything becomes simple.

Physics check:

Two general components of that, in addition to m*g*h. One is accelerating the mass. The easiest way to visualize that is the difference in kinetic energy (1/2m v squared, for the two v's). That's how much it took to accelerate to the higher speed. The second part is that the drag is greater at higher speeds - approximately proportional to speed for rolling and drive train losses and the like, but more importantly proportional to the square of the speed for aero drag. Energy (that portion of it) is that drag force times the distance.

But the extra energy he needed to raise his mass up the hill was just m*g*h. It doesn't matter, for that energy, how fast you do it. The confusion here is that Armstrong is more concerned about power than energy, and power is how much energy is used in a given time. So twice as fast uphill takes twice the power, for just lifting the weight. And approaching eight times the power to overcome drag force from the air. If he's going fast enough, and I assume that Armstrong and Ullrich probably were.

But back to OP, the whole reason I brought this up is asking about hills and calorie burn. Bottom line, just add it in for the climbs, the formula I gave earlier, and that produces the (extra for the hill) calories burned. As opposed to flatter rides.

Well, I'm glad you found your mirror. :thumb:

For an interesting look at the factors involved in energy consumption, speed, weight, headwind, grade, etc. this bicycle calculator is pretty interesting:

Bike Calculator

For a given rider and bike going 20 miles with no elevation, what is your guess as which requires more calories: pedaling 20 mph; pedaling 12 mph; pedaling 12 mph against an 8 mph headwind; or, pedaling 15 mph against an 8 mph headwind?

Answer:

1. 12 mph requires the fewest calories... ~359

2. 12 mph against an 8 mph headwind requires about double the calories as 12 mph with no wind, over the same 100 minutes... ~739

3. pedaling 12 mph against an 8 mph is about the same number of calories as pedaling 20 mph with no wind but takes 40 minutes longer.

4. And what about 15 mph with an 8 mph headwind? The ride is 20 minutes quicker than 8 mph with a headwind and 20 minutes slower that 20 mph without a headwind and requires about 200 more calories than either. ~ 931

And, for BONUS points, how does pedaling at 8 mph on a windless day but up a 5% grade compare with the above?


Same 20 miles but 150 minutes. ~1677 calories.


But-- what 20 mile ride requires the most power?


That would be... 20 mph with no head wind (215 watts); going 15 mph against a 8 mph headwind comes in second (203 watts); and, going only 8 mph but up a 5% grade comes in at 3rd (195 watts). 12 mph against a headwind requires more power (129 watts) than 12 mph with no wind (63 watts).


So, what activity uses the most energy per unit of time?


Going up a 5% grade at 8 mph consumes 1677 calories in 150 minutes. However, pedaling 20 mph with no headwind for the same 150 minutes would consume 1,847.5 calories.

Yes and No.

In air (or any fluid) speed is energy expensive because resistance increases proportional to the square of speed. So you get 4 times the resistance riding at twice the speed. Which is why they promote driving 55 vs 65 to save gas.

OTOH - the work done climbing is purely a function of weight and height gained. Speed isn't a factor in work, so fast or slow,the energy used is the same. OTOH - doing the same work in less time requires more POWER, which is something different. Faster riders of the same weight are more powerful, but the energy they consume doing the same task is the same.

Quickie glossary.

Force is what's needed to move a load against resistance (or accelerate it if no resistance).
Work is the product of Force X the distance moved. Energy used is the work done x the efficiency rating.
Power is the work done per time unit, so those who can work faster are more powerful.

More speed uses more energy-- e.g., above:

Going up a 5% grade at 8 mph consumes 1677 calories in 150 minutes. However, pedaling 20 mph with no headwind for the same 150 minutes would consume 1,847.5 calories.

Try this: You decide to do 200 watts on two rides of ten miles. One ride it flat, the other is 5% up for five miles and 5% down for five miles

Plug the numbers into the calculator, keeping the power at 200 watts.

The flat ride burned 348 calories.

The hill ride burned 375 calories climbing, and then 106 calories descending, for 481 total.

But that's kind of a cheat since that the hill ride took longer. Make the time the same and the calories will turn out the same. Yet the calories per mile will be 48 for the hill ride, and 35 for the flat ride!

I'm going to stop geeking out here before someone complains, but playing with the power calculator is always fun.

...a constant 200 watts is the key -- the 200 watts per minute (12,000 Joules -- about 2.857 food calories) in your examples will be the same by definition. Over a given amount of time the energy used will be the same. And, the rider in the examples above cannot do 20 mph on flat ground without expending more energy -- i.e., >200 watts (~215 watts). More speed takes more power... and, will use up more calories.

I wouldn't say we're consistent with riding conditions ... when we head out for a ride, it's anybody's guess what will happen out there.

Strong headwinds are almost always a given, of course ... but there are usually tailwinds too. It's not at all unusual to have winds gusting up around 50 or 60 km/h here and because of the terrain and the fact that we're on an island so we're surrounded by a large body of water, the wind could come from 15 different directions throughout a ride. I only give wind direction on the weather sites a passing glance now because that's just a rough guideline.

These days we could get pouring rain, hail, a touch of snow, sunshine, temps as low as about 0C or as high as about 16C ... all on one ride! All of that all on one ride doesn't usually happen, but there is often quite a variety and we go prepared for anything.

Then there is the terrain. Tasmania is hilly.

And the roads ... sometimes we're on smooth pavement, often we're on quite rough pavement. They don't maintain the roads particularly well here ... doesn't seem to be a priority. We've done many rides where we've felt pretty beat up by the end just simply because the roads have been that rough. And several of our routes are a combination of pavement and gravel. One of the ways they keep the traffic volume down on country roads (and probably keep the maintenance costs down) is to leave several km somewhere in the middle as gravel.

The 100K we do as part of the Audax Tasmania calendar at the beginning of the season (early November), for example, starts with a lovely quiet scenic loop on a rather rough road, with two patches of gravel that total about 7 km. Then there's another lovely quiet scenic loop with a gravel stretch about 3 km long, up a fairly steep hill.



And of course we plan our weekends to do different routes and go different places, so we encounter all sorts of stuff. :)

Just a brief update. On my last ride, a week ago, we did a lot of climbing and I was pathetic. Very close to bonking and generally no energy. The day after, i could barely stay awake. I was exhausted constantly. After some discussion with knowledgeable friends and some contemplation I concluded that it was probable that I had cut carbs too severely. The result was a meltdown in energy and I still wasn't losing any weight. So, I began putting things like bread and potatoes back into my diet. Two things happened. I quickly began to feel better and then I began to lose weight. The weather here has been so hot/humid that we haven't ridden but I continue to feel great and I'm losing weight. I'm now down to 186 lbs.

As it is said, "Fat burns in a carbohydrate fire." Way to go!

Why you shouldn't exercise to lose weight, explained with 60+ studies - Vox......here's something to confuse you even more:

Haven't read the article yet but I was thinking about this today. If you rely on activity to lose weight thane you gain it back with less activity. But, if you lose weight via choice of food and amount, activity becomes something that you fuel with your food choices. It doesn't have a transitory influence on weight but is critical for the proper function of your body.

FWIW....down to 185 this morning. This with no exercise for about 8 days.