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Maths Problem

2

Comments

  • #32
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    According to here my BMR is : 2388 Calories Per Day.

    *note I chose the 1-3 day exercise option.

    Information Thus Far:
    Target bodyfat Loss: 1 Kg
    Age: 35 years
    Height: 179 cm
    Weight: 74 kg
    Fat Burn Zone: 111-130bpm
    Basal Metabolic Rate: 1,689 - 2388 cal/hr
    Energy per hour (not exercising): 70.375 - 99.5 cal/hr
    Energy per hour (Zone 3): X cal/hr
    Energy per hour from fat (Zone 3): X*(0.75) cal/hr
    Target distance in Zone: Y km

    What is X and Y?


  • #33
    ROK ON
    Closed Accounts Posts: 6,831 ✭✭✭ROK ON


    Pete
    To the extent that this is a mathematical issue that implies that it can be solved by testing and experimentation.

    To the extent that you want answers from the interweb suggest that you lack motivation go experiment and you want to know what others may have done relating to this issue.

    You have some of the data, but have some missing variables.
    Why not get on your bike and measure how long it takes to burn that 1kg of fat.
    When you get the answer be a nice chap and let us know.


  • #34
    NeedMoreGears
    Registered Users, Registered Users 2 Posts: 1,419 ✭✭✭NeedMoreGears


    petethedrummer wrote: »
    Yes but I want to know how far I have to cycle to achieve this.

    At 30kph you'd put about 185W on the pedals. (flat , still air)

    Assuming a typical efficiency for your body of 24% thats 771W fat/carb consumption. At 4182kj/kcal, that equates to 0.84kcal/s or 663kcal/hr.

    The key is the fat/carb ratio. Some suggest that the fat/carb ratio at low effort/rest is about 50/50. At 30kph you're probably working so this might drop to 35/65 . (http://www.active.com/triathlon/Articles/The-Myth-of-the-Fat-burning-Zone.htm). In effect you're burning 232 kcal of fat per hour or 7.74 per km.

    Therefore you need to cycle 995km at 30kph to burn off 1kg of fat ; although you'd have also had to consume about twice that energy in carbs.

    Sounds a bit much to me but even if all the energy came from fat it still comes to 348km at 30kph.


  • #35
    Lumen
    Registered Users, Registered Users 2 Posts: 30,478 ✭✭✭✭Lumen


    niceonetom wrote: »
    The leanest athletes I see tend to be the ones that do lots of very explosive/anaerobic stuff

    I read a few pro cyclist autobiographies, though probably fewer than you.

    They're all totally obsessed with being light and eating almost nothing. I'm not convinced that the Riis fizzy-water-and-sleeping-pill approach has been completely abandoned, even in the Age Of Sky.

    Whereas non-pro cyclists, particularly new ones, seem obsessed with feeding themselves as much as possible. If it's not on-the-bike "nutrition" it's recovery drinks. Even the retrogrouches bang on about bowls of porridge before a "spin". I believe this to be rooted in the fact that fatties are overrepresented in the body of recreational cyclists on account of people taking up cycling to lose weight.

    So, whilst I acknowledge that there are anecdotes about amateurs losing weight and getting slow/sick/overtrained/underecovered, I just don't see why if pros can eat relatively nothing and get faster then amateurs can't do the same. Unless a necessary component is lounging around like a pro for 8 hours a day and avoiding all contact with humanity.


  • #36
    killalanerr
    Registered Users, Registered Users 2 Posts: 1,322 ✭✭✭killalanerr


    Lumen wrote: »
    So, whilst I acknowledge that there are anecdotes about amateurs losing weight and getting slow/sick/overtrained/underecovered, I just don't see why if pros can eat relatively nothing and get faster then amateurs can't do the same. Unless a necessary component is lounging around like a pro for 8 hours a day and avoiding all contact with humanity.

    Ya im with Lumen on this one,i have cut my pre ride meal down to one banana and a cupa tea in an effort to louse some weight and have had no problem geting round a 100k club spin on a few litres of water,the trick is not to eat rings round yourself when you get home,
    I wouldnt try this as a complete newbie but any one with a few winters under their belt might be surprised how little they need to eat


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  • #37
    Ole Rodrigo
    Closed Accounts Posts: 3,013 ✭✭✭Ole Rodrigo


    I make it 350 km at 27 kph.

    Round it off at 400 and do the extra bit in the rain. Be grand.


  • #38
    RayCun
    Registered Users, Registered Users 2 Posts: 15,704 ✭✭✭✭RayCun


    petethedrummer wrote: »
    Information Thus Far:
    Target bodyfat Loss: 1 Kg
    Age: 35 years
    Height: 179 cm
    Weight: 74 kg
    Fat Burn Zone: 111-130bpm
    Basal Metabolic Rate: 1,689 - 2388 cal/hr
    Energy per hour (not exercising): 70.375 - 99.5 cal/hr
    Energy per hour (Zone 3): X cal/hr
    Energy per hour from fat (Zone 3): X*(0.75) cal/hr
    Target distance in Zone: Y km

    The three lines I have crossed out are not 'information', they are ranges so broad as to be meaningless. If you want actual information, try this place
    http://www.ucd.ie/sportandhealth/sss/laboratory/
    or somewhere like it


  • #39
    Lumen
    Registered Users, Registered Users 2 Posts: 30,478 ✭✭✭✭Lumen


    Also consider spending more time cold and naked, particularly at night time.

    22C->16C would raise your BMR by 5.6%.

    http://www.nature.com/ejcn/journal/v56/n4/full/1601308a.html

    Maths!! Academic references!


  • #40
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    RayCun wrote: »
    The three lines I have crossed out are not 'information', they are ranges so broad as to be meaningless. If you want actual information, try this place
    http://www.ucd.ie/sportandhealth/sss/laboratory/
    or somewhere like it
    Thanks Ray but I can't pick through that. weight loss is supposed to be simple. reading through all that is not simple.


  • #41
    DaithiMC
    Registered Users, Registered Users 2 Posts: 349 ✭✭DaithiMC


    petethedrummer wrote: »
    According to here my BMR is : 2388 Calories Per Day.

    *note I chose the 1-3 day exercise option.

    Information Thus Far:
    Target bodyfat Loss: 1 Kg
    Age: 35 years
    Height: 179 cm
    Weight: 74 kg
    Fat Burn Zone: 111-130bpm
    Basal Metabolic Rate: 1,689 - 2388 cal/hr
    Energy per hour (not exercising): 70.375 - 99.5 cal/hr
    Energy per hour (Zone 3): X cal/hr
    Energy per hour from fat (Zone 3): X*(0.75) cal/hr
    Target distance in Zone: Y km

    What is X and Y?

    Ok, so if you do a workout on the bike and use, say, Strava, it will give you an estimated caloric value for the entire ride. If your spin is two hours divide that by two to get X. You will also have the total distance travelled so if your spin was uniform in intensity (assume you spend calories at a linear rate over the total distance) you can graph a number of points and extract your Y target value.


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  • #42
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    I made a mistake earlier, I should have picked the sedentary option. 2084 is the new upper BMR value.

    Information Thus Far:
    Target bodyfat Loss: 1 Kg
    Age: 35 years
    Height: 179 cm
    Weight: 74 kg
    Fat Burn Zone: 111-130bpm
    Basal Metabolic Rate: 1,689 - 2084 cal/hr
    Energy per hour (not exercising): 70.375 - 86.83 cal/hr
    Energy per hour (Zone 3): X cal/hr
    Energy per hour from fat (Zone 3): X*(0.75) cal/hr
    Target distance in Zone: Y km

    What is X and Y?


  • #43
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    DaithiMC wrote: »
    Ok, so if you do a workout on the bike and use, say, Strava, it will give you an estimated caloric value for the entire ride. If your spin is two hours divide that by two to get X. You will also have the total distance travelled so if your spin was uniform in intensity (assume you spend calories at a linear rate over the total distance)
    Do I have to buy a smart phone or a fancy bike computer to do this? Do they give out their formulas for calculating the spent calories?

    DaithiMC wrote: »
    you can graph a number of points and extract your Y target value.
    We may need to graph a few things here but I'm hoping to keep this as simple as possible.


  • #44
    DaithiMC
    Registered Users, Registered Users 2 Posts: 349 ✭✭DaithiMC


    petethedrummer wrote: »
    I made a mistake earlier, I should have picked the sedentary option. 2084 is the new upper BMR value.

    Information Thus Far:
    Target bodyfat Loss: 1 Kg
    Age: 35 years
    Height: 179 cm
    Weight: 74 kg
    Fat Burn Zone: 111-130bpm
    Basal Metabolic Rate: 1,689 - 2084 cal/hr
    Energy per hour (not exercising): 70.375 - 86.83 cal/hr
    Energy per hour (Zone 3): X cal/hr
    Energy per hour from fat (Zone 3): X*(0.75) cal/hr
    Target distance in Zone: Y km

    What is X and Y?

    By the way, if weight loss is the absolute goal here many physical trainers will tell you it is something like 80% food, 20% exercise that will produce best results. So starving yourself in a systematic way will yield faster and more significant results than exercise and caloric intake at or above your BMR.


  • #45
    DaithiMC
    Registered Users, Registered Users 2 Posts: 349 ✭✭DaithiMC


    petethedrummer wrote: »
    Do I have to buy a smart phone or a fancy bike computer to do this? Do they give out their formulas for calculating the spent calories?


    We may need to graph a few things here but I'm hoping to keep this as simple as possible.

    You will have to do some experimental work to get some of the variables for you're calculations. If you have s gym membership you could do it on a bike there, they give all the numbers but again would be estimates.

    Otherwise, yes a smartphone, but not necessarily a fancy bike computer would be needed. At the very least it would be good to have a speedo to keep your rate consistent


  • #46
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    NeedMoreGears wrote: »
    Assuming a typical efficiency for your body of 24% thats 771W fat/carb consumption. At 4182kj/kcal, that equates to 0.84kcal/s or 663kcal/hr.
    how did you go from 4182kj/kcal to 0.84kcal/s
    NeedMoreGears wrote: »
    The key is the fat/carb ratio. Some suggest that the fat/carb ratio at low effort/rest is about 50/50. At 30kph you're probably working so this might drop to 35/65 . (http://www.active.com/triathlon/Articles/The-Myth-of-the-Fat-burning-Zone.htm). In effect you're burning 232 kcal of fat per hour or 7.74 per km.

    I want this as efficient as possible so I will be going slow. So 50/50 sounds reasonable.
    NeedMoreGears wrote: »
    Therefore you need to cycle 995km at 30kph to burn off 1kg of fat ; although you'd have also had to consume about twice that energy in carbs.
    995Kms? So if someone was 20kg overweight they would have to do 995*20 kms to get down to their correct weight. How far away is that? anyway we'll do the full maths just to confirm everything.

    Also why would I need to eat twice the energy in carbs? I don't understand the reasoning.


  • #47
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    Lumen wrote: »
    Also consider spending more time cold and naked, particularly at night time.

    22C->16C would raise your BMR by 5.6%.

    http://www.nature.com/ejcn/journal/v56/n4/full/1601308a.html

    Are you volunteering to take my temperature?


  • #48
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    petethedrummer wrote: »
    995Kms? So if someone was 20kg overweight they would have to do 995*20 kms to get down to their correct weight. How far away is that? anyway we'll do the full maths just to confirm everything.
    It's this distance x 4.

    Where as I only have to go from Elmshorn, Germany to auxerre, France plus a 2km diversion for lunch.

    I think it helps to visualise goals but I don't think those numbers are correct.


  • #49
    slideshow bob
    Registered Users, Registered Users 2 Posts: 380 ✭✭slideshow bob


    petethedrummer wrote: »
    995Kms? So if someone was 20kg overweight they would have to do 995*20 kms to get down to their correct weight.

    That's the distance that would burn 3kg of fat if only fat were used as fuel. As NeedMoreGears says, his assumption is about a third of these come from fat, and two thirds from carbs.

    Back to losing 1kg of bodyweight...
    1) Train med-high intensity at lunchtime
    2) Dont eat until evening
    3) Repeat until bodyweight down 1kg.

    2) helps because the metabolic rate is elevated for some time after exercise. Once your glycogen is gone, your body has to burn fat. A few iterations will do it.


  • #50
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    slideshow bob wrote: »
    That's the distance that would burn 3kg of fat if only fat were used as fuel. As NeedMoreGears says, his assumption is about a third of these come from fat, and two thirds from carbs.
    It's not clear what he meant, he never mentioned 3kgs.


    "Some suggest that the fat/carb ratio at low effort/rest is about 50/50. At 30kph you're probably working so this might drop to 35/65 . (http://www.active.com/triathlon/Arti...rning-Zone.htm). In effect you're burning 232 kcal of fat per hour or 7.74 per km.

    Therefore you need to cycle 995km at 30kph to burn off 1kg of fat ;"


    I'm confused.:confused:


  • #51
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    slideshow bob wrote: »
    Back to losing 1kg of bodyweight...
    1) Train med-high intensity at lunchtime
    2) Dont eat until evening
    3) Repeat until bodyweight down 1kg.

    2) helps because the metabolic rate is elevated for some time after exercise. Once your glycogen is gone, your body has to burn fat. A few iterations will do it.
    How long do glycogen stores last if I take this approach? I want to get at the fat and only get 30 mins for lunch.

    Edit: Actually don't answer that, I want to keep this to Fat burning zone only. This will only complicate things.


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  • #52
    zbluebirdz
    Registered Users, Registered Users 2 Posts: 270 ✭✭zbluebirdz


    Weight: 74 Kg
    Average calories burnt per hour (20Km/hr): 500
    Calories in 1 Kg: 7700

    =====
    100% fat burning zone:
    Distance to cycle: ( 7700 / 500 ) * 20 = 308 Km.
    Time: ( 7700 / 500 ) = 15.4 hours

    50% fat burning zone:
    Distance to cycle: ( ( 7700 / 500 ) * 20 ) * 2 = 616 Km.
    Time: ( 7700 / 500 ) * 2 = 30.8 hours
    =====

    If your weight is higher, then it'll take you less time/distance to burn off 1 Kg. However, the lighter you become, it takes more time/distance to burn off the next 1 Kg ...


    So, for the OP, it'll take you approximately 600 Km to burn off 1 Kg of fat. :)

    How far is 600 Km? A round trip from Dublin to Tralee and back.


    NB: I'm no expert on this topic/subject matter. :D


  • #53
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    Information Thus Far:
    Target bodyfat Loss: 1 Kg
    Age: 35 years
    Height: 179 cm
    Weight: 74 kg
    Fat Burn Zone: 111-130bpm (estimated)
    Speed (at Zone: 20km/h (estimated)
    Basal Metabolic Rate: 1,689 - 2084 cal/day (estimated)
    Energy per hour (not exercising): 70.375 - 86.83 cal/hr
    Energy per hour (Zone + BMR): 500 cal/hr
    Energy per hour (Zone exercise alone): 413.17 - 429.625 cal/hr
    Energy per hour from fat (Zone exercise alone 75% fat burning): 309.8775 - 322.215 cal/hr
    Time to burn 7700 cal of Fat: 23.9-24.9hrs
    Target distance in Zone: 477.94 - 496.97km


    Being pessimistic I have to eat 1,689 calories per day and travel 496.97km
    Being optimistic I have to eat 2084 calories per day and travel 477.94kms

    I'll need to do further reading to confirm the numbers above. and to check my logic. which I'm pretty sure is wrong.


  • #54
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    zbluebirdz wrote: »
    If your weight is higher, then it'll take you less time/distance to burn off 1 Kg. However, the lighter you become, it takes more time/distance to burn off the next 1 Kg ...
    I'll confirm this later with maths.


  • #55
    Ole Rodrigo
    Closed Accounts Posts: 3,013 ✭✭✭Ole Rodrigo


    petethedrummer wrote: »
    I'll confirm this later with maths.

    ' You won't find an equation to pedal up a hill '

    - old chinese saying


  • #56
    NeedMoreGears
    Registered Users, Registered Users 2 Posts: 1,419 ✭✭✭NeedMoreGears


    @pete

    You're confused? I'm confused.

    I also cannot type.

    771w = 771 joules per second. There are 4.182kcal in a kj (When people talk about calories, they actually mean kilocalories). Hence dividing by 771 by 4.182 and then by 1000 gives 0.184 kcal/sec (sorry not 0.84). Hence 663 kcal/hr. i.e 22kcal per km or so.

    If 35% of this energy comes from stored body fat then you burn 232 kcal of fat doing the 30km. Hence for a full kilo (i.e. 7700kcal worth) you need to travel the 995km. i.e. you only burn around 7.75 grammes of fat per km at that speed (232/30)

    The other energy should come from more immediately available energy sources (glycogen??) stored in your muscles. The bit I don't fully (actually not even a tiny bit) understand is how glycogen is replaced if say you don't eat enough calories to replace those you consumed on the bike.

    Anyway if I were you I'd go for broke. Aim for 2.5kg which is 2487km ; that gets you to Rome with 20k to spare. You'll have earned that post ride espresso.


  • #57
    smacl
    Moderators, Society & Culture Moderators Posts: 15,962 Mod ✭✭✭✭smacl


    Just a thought that came to me on the bike yesterday, but does one burn a considerably larger amount of energy exercising in colder conditions? Seemed to me that as much energy was being burnt keeping warm as going forward. No idea how this pans out in your equations.

    I'd suggest you need to calibrate your model based on putting the kms into the road, stabilizing and diet, and measuring changes in weight / fat mass. Anything other than dead flat, and energy burnt climbing hills will vary based on weight, and wind and weather will also play their part. To me, it seems like there are too many unaccounted for variables in play for your mathematical model to be reliable unless tested and adjusted accordingly.


  • #58
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    My heart rate will be in the fat burning zone. Rendering all other variables moot.


  • #59
    smacl
    Moderators, Society & Culture Moderators Posts: 15,962 Mod ✭✭✭✭smacl


    petethedrummer wrote: »
    My heart rate will be in the fat burning zone. Rendering all other variables moot.

    Fair enough, but then the result you're looking for is number of hours training at a given HR. This might bear little relation to actual distance covered which would require that the calories are being burnt at a rate proportional to distance traveled, which could hold true indoors on the turbo, but less so in varied terrain and weather.


  • #60
    petethedrummer
    Registered Users, Registered Users 2 Posts: 7,604 ✭✭✭petethedrummer


    We'll assume its a nice day and I'm taking a flat route and there's no wind.

    Hours will do if it becomes to complex to translate to distance.


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  • #61
    smacl
    Moderators, Society & Culture Moderators Posts: 15,962 Mod ✭✭✭✭smacl


    petethedrummer wrote: »
    We'll assume its a nice day and I'm taking a flat route and there's no wind.

    Sounds like paradise... :)

    https://www.youtube.com/watch?v=Wrh4r2JJBxA


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