Is there a way to calculate weight loss rate by riding 5 days a week on rollers, an hour a day, at 300watts average?

http://bikecalculator.com/ suggests 4300kcal or 0.13kg per hour but I suspect it’s a lot more complicated than that.

If you can put out 300W for an hour, 5 days a week then the weight loss should be handling itself! Stop eating so much 😉

If you put the figures for food/ exercise and your weight into myfitnesspal it would do the maths for you!

You have to divide by 4 (as the body is only 25% efficient, very roughly) so around 1080kCal per hour. Are you sure about the 300W for an hour – that’s pretty good going!

I work on the principal that for every hour cycling I loose nothing !! But for every piece of cake I put 0.5kg on. I know I’m right 🙁

more for curiosity than anything. I can squeeze in an hour before breakfast and just wondered what would happen.
300w might be optimistic at the moment over an hour with warm up and cool down, but I was at 340w this time last year 🙁

if the body’s only 25% efficient, you’d have to multiply by 4 wouldn’t you? (hang on – I think that’s probably what you did anyway)

(and you may lose a bit more due to a bit extra thermogenesis, I think)

You are confusing “calories” and “Calories” the latter are 1000 time bigger than the former which is what the calculator is showing, the label is “KJ/ calories”, note the lowercase ‘c’. There’s 4.18KJ per Calorie so you need to divide the figure shown by 4.18 to get the number of Kc/Calories.

Fat is around 9 cal a gram. Your body will also be using up glucose and glycogen first. Glucose is 4 cal gram, not sure about glycogen.

Also, in the food world a calorie is in fact a kilocalorie. Not sure why!

Ah, sorry, didn’t see that last post…

So weight used up would be somewhere between a kilo and 500g per day. If you didn’t then eat something to replenish yourself. Which you would!! 🙂

Some interesting stuff here

Also, in the food world a calorie is in fact a kilocalorie. Not sure why!

https://en.wikipedia.org/wiki/Calorie

OK.

300 Watts = 300 Joules per second
3600 seconds/hour
300 * 3600 = 1080000 Joules = 1080 KJ
4.18 KJoules per kilocalorie or Calorie
1080/4.18 = 258 Calories

That’s the actual work done but since the body is only around 25% efficient you don’t need to do the last division so stick with 1080KJ or 1080 Calories.

riding 5 days a week on rollers, an hour a day, at 300watts average?

= hungry + tired
= eating more + resting more
= slight weight gain

300W into the pedals (assuming 100% efficiency) means burning 258 Calories or 258 kCal (same thing – as long as you watch the capitalisation).

As I said above though, the body is only roughly 25% efficient so you burn 1000 Calories an hour (roughly) to produce 300W for an hour. The rest goes into friction and heat.

Are you measuring power with a power meter or virtual power?

I’m using stages. Thanks for the input all, I suspect I’m gonna be making some dietary changes as well but I was interested to know if I could do it solely on rollers. The last few years I’ve been doing 20 hours of decent training a week and not really worrying about the food, but this year I’m down to the work commute and a couple of good rides at the weekend, no objectives other than to keep the kilos off.