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Calories Burned

NavrigNavrig Posts: 1,352
edited September 2013 in Training, fitness and health
I am trying to get leaner for next year's trip to the alps - this year's trip taught me a lot about fitness (lack of it), climbing and the benefits of being a bit lighter.

I am not looking a signifcant weight loss, basically 84kg down to about 74kg, 70kg if I can manage.

My plan was to keep an accurate diary of what I eat, focus on healthy eating and increase my training levels. I use an app which will shows a net calorie gain/loss for the day, week and month.

So far I am doing OK on all 3 accounts but I have some doubts on the accuracy of the app/website calculations of RDI and calories burned. Their database of foodstuffs seems reasonably accurate when compared to labels.

So I am looking for advice or guidance.

I am 50, 84kg, active with an increasing level of exercise. What would be a typical RDI as far as colries are concerned?

On Saturday our regular training ride was 47 miles over 3 hours 15 mins inlcuding a long puncture stop. Say 3 hours so about 15mph. Again typically, what would the calories burned be?

Posts

  • phreakphreak Posts: 2,350
    A power meter is the best way of doing it. Without it, it's very difficult to know for sure.

    Here's a calculation for figuring it all out
    To work out energy expenditure in joules, you multiply average power (/1000) by time in seconds. Thus, the work done in 1-hr at 190 W avg is 684 kj (0.19 x 3600). To convert this to kcal you divide by 4.18, i.e., 164 kcal.

    However, the human body when cycling is only around 25% efficient (normal range ~ 20 - 26%), thus, this needs to be calculated, to work out the human energy consumption, i.e., 164 / 0.25 = 656 kcal.

    I know it's disputed, but a rule of thumb for an endurance ride is 600 calories an hour, which using the above would work out at 166 watts for an hour, which I suspect is quite doable for most people.

    If you're looking to lose weight it probably doesn't do any harm to underestimate a little with these things.

    For what it's worth, I use a BMR of 1800, and add onto that any exercise I do each day. Subtract what I eat and try and ensure the numbers are the right side each day. Dare say it's not perfect, but I'm 56kg at the moment so it seems to be working.
  • NavrigNavrig Posts: 1,352
    phreak wrote:
    A power meter is the best way of doing it. Without it, it's very difficult to know for sure.

    Here's a calculation for figuring it all out
    To work out energy expenditure in joules, you multiply average power (/1000) by time in seconds. Thus, the work done in 1-hr at 190 W avg is 684 kj (0.19 x 3600). To convert this to kcal you divide by 4.18, i.e., 164 kcal.

    However, the human body when cycling is only around 25% efficient (normal range ~ 20 - 26%), thus, this needs to be calculated, to work out the human energy consumption, i.e., 164 / 0.25 = 656 kcal.

    I know it's disputed, but a rule of thumb for an endurance ride is 600 calories an hour, which using the above would work out at 166 watts for an hour, which I suspect is quite doable for most people.

    If you're looking to lose weight it probably doesn't do any harm to underestimate a little with these things.

    For what it's worth, I use a BMR of 1800, and add onto that any exercise I do each day. Subtract what I eat and try and ensure the numbers are the right side each day. Dare say it's not perfect, but I'm 56kg at the moment so it seems to be working.

    Thanks for this.

    I appreciate that most of this is guestimating.

    So 3 hours at 656 calories per hour equates to 1968 calories. The app indicates I burned 2828 calories in 3 hours 15 so adjusting to 3 hours that would be 2610 calories. That's a big difference and makes the app almost useless as a tool to be relied upon.

    I'll have to look at alternative methods.
  • phreakphreak Posts: 2,350
    The app is guessing just as much as we are really. It doesn't know how hilly the route was or whether you had a strong headwind.
  • NavrigNavrig Posts: 1,352
    phreak wrote:
    The app is guessing just as much as we are really. It doesn't know how hilly the route was or whether you had a strong headwind.

    That is true, nor if I have an ultra-lite super smooth bike or a rusty sit up and beg HOWEVER if both methods assume a flat course, typical bike and no headwind (why assume anything else) then the numbers should be a bit closer.

    That said this website gives 2592 calories. http://www.sparkpeople.com/resource/calories_burned.asp


    It seems the app's RDI calcs are also a bit wayward. It has set mine at 2700 calories whilst a more respected website calculates it as 2150 calories. http://caloriecount.about.com/tools/calories-goal
  • dw300dw300 Posts: 1,642
    15,000g in 300days (keeping the numbers round) = 50g/day. You're probably gona want to have 450kcals/day or 3,150kcals/week of a deficit that you want. If you get 2000kcals of that from exercise then you only need a weekly deficit of 1,150kcals, or 165kcal/day from eating.

    This seems very easy, you should be able to do it with your current exercise level and simply not snacking. But for every week you break even, you have to double your loss another week, or more if you gain weight. So just do it steadily, and monitor your progress so that you don't end up requiring some huge daily deficit near the end that will actually affect your training.

    Do you know how to use Excel, or any other spreadsheet?

    Take all the guesswork out and just record data for date and daily weight. Then make a graph for each 30days and plot a trendline which will smooth data and account for measuring errors. You should easily be able to see whether you are on course for your required loss for that month doing no more than record your weight. Then all you have to do it try a bit harder with exercise or diet for a few days to get back on track.

    Most peoples problem is not giving themselves a realistic time to do this, they think everything will happen best case scenario. But this way you shouldnt deviate too much from what you need to do and you'll catch it quick if you start to drift the wrong direction.

    Good luck, and remember you'll really enjoy your holiday if you achieve this, so go for it.
    All the above is just advice .. you can do whatever the f*ck you wana do!
    Bike Radar Strava Club
    The Northern Ireland Thread
  • bahzobbahzob Posts: 2,195
    I'm 5'8", a bit older than you, used to weigh 90kg, now weigh 70kg and am planning to lose a few more kg for next year.

    The most effective way to lose weight I have found is do as you are doing, measure cals in vs cals out and aim for a consistent deficit and lose weight gradually over time. Re calories for cycling I have a powermeter which helps a lot and would agree with the results above of around 600 cals per hour for solo rides, it will be less if you are in a group.

    My main advice would be differentiate losing weight from training and give one or other a clear priority according to time relative to any performance targets you may have. So if aiming to lose weight focus on maintaining you calorie deficit, eat normal meals and don't use any special sports products (including during/after rides). It's very easy to fall into the trap of thinking that a bit of extra exercise makes it OK to have a bit more food and end up undoing all the hard work you have done.
    Martin S. Newbury RC
  • XherdanXherdan Posts: 48
    You don't actually need to know precisely how many calories you burn. If you weigh yourself, record your calorie intake for a week and what your calorie calculator for your riding says you burned and then weigh yourself again at the end of the week then you can use these to get a rough idea of how inaccurate your calculator is. Once you know these things you know that if you ensure the same calorie intake and same calculator for calories expended on the bike then you know you will achieve the same amount off weight loss as you did in the week you recorded everything. Additionally you can use one of those weight loss calculators to work out in reverse a more accurate figure for what you expended cycling + other activities in the week.

    For example according to the default data on this site for a 25 y/o male at 5ft10 and 160lb 500 calories a day less=1lb weight loss per week (http://www.calculator.net/calorie-calculator.html). If you are eating 500calories over what is required to maintain your weight and still lose 1lb a week then you know you are expending 1000cal in order to achieve a value of 500 calories below the level required to maintain your weight.
  • NavrigNavrig Posts: 1,352
    Thanks for all the sound advice.

    Keeping a diary will help with discipline and, hopefully, make me feel guilty when the discipline slips.

    So far the hardest thing to cope with are business lunches where you are presented with trays of sandwiches of unknow content and trays of pastries.
  • bahzobbahzob Posts: 2,195
    Navrig wrote:

    So far the hardest thing to cope with are business lunches where you are presented with trays of sandwiches of unknow content and trays of pastries.

    Yes I can certainly sympathise there. Never really managed to sort it either. Trying to eat nothing just didn't work. Luckily business lunches are a thing of the past now, but if I was still faced with the temptation I might try eating something small and rich in protein like a boiled egg at the start to try and take the edge off appetite.

    Good luck, you will really see the benefit once you get to the Alps.
    Martin S. Newbury RC
  • okgookgo Posts: 4,368
    Business lunches are the bain of my life too. Especially as I usually have a few drinks with them! But can't change everything just for a hobby.
    Blog on my first and now second season of proper riding/racing - www.firstseasonracing.com
  • Navrig wrote:
    I am trying to get leaner for next year's trip to the alps - this year's trip taught me a lot about fitness (lack of it), climbing and the benefits of being a bit lighter.

    I am not looking a signifcant weight loss, basically 84kg down to about 74kg, 70kg if I can manage.

    My plan was to keep an accurate diary of what I eat, focus on healthy eating and increase my training levels. I use an app which will shows a net calorie gain/loss for the day, week and month.

    So far I am doing OK on all 3 accounts but I have some doubts on the accuracy of the app/website calculations of RDI and calories burned. Their database of foodstuffs seems reasonably accurate when compared to labels.

    So I am looking for advice or guidance.

    I am 50, 84kg, active with an increasing level of exercise. What would be a typical RDI as far as colries are concerned?

    On Saturday our regular training ride was 47 miles over 3 hours 15 mins inlcuding a long puncture stop. Say 3 hours so about 15mph. Again typically, what would the calories burned be?

    There's no need to count calories or obsess about RDI's etc. Intermittent fasting is the easy way to control or lose weight. Most days I incorporate a 16 hour fast and my weight has been stable (75kgs with a decent amount of muscle mass) for the last 10 years (coming up on 40 now) If you want to shed weight then throw in a couple of fasted training rides of an hour or so each week and the weight will come off. Eat sensibly and time your intake to when you most need it, i.e after a hard training session.
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