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Discussion Starter · #1 ·
I've read that working at a lower to moderate heart rate and excercise intensity will..and excuse my lack of proper terms.. run your body on it's fat metabolisim, while intense workouts use another source of fuel. I know I didn't say that right, but some of the training bibles say that if you constantly work out at high intensity only, you aren't using the system that burns up fat. Anyway..I never really bought into that, and have been training at pretty high intensity once the racing season starts up. I weigh about 165 in racing shape with an 8% body fat skin fold test.

Well, a few weeks with a tweeked back kept me from racing and my sessions on the bike were short and painful, so I gained up to 170-173.

It didn't take long to get back my fitness once the back pain went, but the extra weight stayed on..Nothing in my normal training seemed to be helping me drop back to weight. I decided to combine my regular training with some long low intensity ridea, like suggested by the books...Wow! In just ten days, the extra lbs came right back off, along with a couple more lbs and I feel better than ever on the bike now.

So, perhaps if you need to shed a couple lbs. you might try what worked for me and what those books said..Ride some long low intensity days..I know it's hard to find time to do during the race season...I actually skipped a TT to ride a mountain century at touring pace

.I still stick a couple of sets of intervals into these long rides...Can't help myself there.. If I find myself with extra lbs again, I'll do some more loong moderate rides again and burn off the fat..It works.
Don Hanson
 

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put simply, at a certain level of itensity, your body cannot process enough oxygen effectively to burn fat. you will lose weight if calories burned is greater than calories consumed. this remains true no matter how slowly you ride
 

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bauerb said:
put simply, at a certain level of itensity, your body cannot process enough oxygen effectively to burn fat.
I don't think that is quite the right way to look at. Carb vs. fat use basically comes down to the muscle demand for energy. Oxidizing fats is a much slower process than oxidizing carbs, hence at high work rates muscle cells rely more on glycolysis and oxidation of its products rather than oxidation of fat. After all, at your highest rates of oxygen consumption you're burning almost nothing but carbs, where as at at rest when oxygen comsumption is low you're burning fat.
 

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That's a bunch of crap.

Ride hard and eat less.
 

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When not riding

Dwayne Barry said:
I don't think that is quite the right way to look at. Carb vs. fat use basically comes down to the muscle demand for energy. Oxidizing fats is a much slower process than oxidizing carbs, hence at high work rates muscle cells rely more on glycolysis and oxidation of its products rather than oxidation of fat. After all, at your highest rates of oxygen consumption you're burning almost nothing but carbs, where as at at rest when oxygen comsumption is low you're burning fat.
Yes, but when he quits riding (and his metabolism has slowed down) then if he eats less, he will burn more fat. He lost weight because he was either burning more calories or eating less. The nature of his metabolic pathways while exercising is not that relevant. He was likely burning around 200 calories of fat an hour and IF he ate less relative to his total caloric demand, then that fat was not replaced when he was off the bike. Even if he was doing all super high intensity while on the bike, if he ate less relative to his total caloric demand, then his body would tap his fat stores for energy while he was not riding, and burn that fat. The amount of shift in metabolic pathways has minimal effect compared to the overall thermodynamics of calories consumed vs. calories burned.
 

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Dwayne Barry said:
After all, at your highest rates of oxygen consumption you're burning almost nothing but carbs, where as at at rest when oxygen comsumption is low you're burning fat.
I think you have it all wrong here, its called aerobic (ie utilizing oxygen). Aerobic metabolism requires fat to enter to metabolic cycle.
High Intensity Exercise does use a lot of anaerobic (carbs) for fuel, but at best after less than a minute, a trained person is still using aerobic metabolism for energy.

At rest your bodie's main fuel source is fat almost exclusively.
 

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Discussion Starter · #8 ·
Well, whatever the metabolic processes are that are involved, incorporating some longer duration but lower intensity rides pulled off those 'sticky' lbs. when nothing else I was doing seemed to make any difference.

I've worked into a pretty good feeling for my own conditioning over the years and "riding harder" just makes me 'flat' and over-trained (according to all the overtraining markers cited in the books) Eating carefully has always been part of my program once I learned how effective being lean is.

So the thing that worked for me was to do some 4-5 hour rides, keeping my HR down. I did these about 3 days per week, with my normal training and racing. Some of the long rides, I will do some strength pedaling, climb a few thousand feet at slow cadence/high load, while still keeping my HR reasonably low. That seems to be helping my leg strength as well..

An unanticipated side effect of this kind of training is...Re-discovering the enjoyment of cycling as a 'regular biker' again. Going out and just having fun on a ride rather than (trying to) doggedly stick to a structured workout. Riding again with my S.O. I forgot how much fun cycling can be, besides just the racing and training parts of it.

Don Hanson
 

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At lower intensities you can use a larger percentage of fat stores for energy, but at higher intensities you burn more total calories which is what losing weight is all about.
 

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Bocephus Jones II said:
At lower intensities you can use a larger percentage of fat stores for energy, but at higher intensities you burn more total calories which is what losing weight is all about.
Sorta true. Per minute you'll definitely burn more calories at a higher intensity. The question is how many minutes you can go. I can do 1000 Kj in an hour, but I can't hold that pace for three hours. Now if I ride at a stiff-moderate pace I can do 600 Kj an hour, but can hold that pace for 3-4 hours, resulting in a higher overall burn.

I'm sure that this was why the OP lost weight.
 

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shawndoggy said:
Sorta true. Per minute you'll definitely burn more calories at a higher intensity. The question is how many minutes you can go. I can do 1000 Kj in an hour, but I can't hold that pace for three hours. Now if I ride at a stiff-moderate pace I can do 600 Kj an hour, but can hold that pace for 3-4 hours, resulting in a higher overall burn.

I'm sure that this was why the OP lost weight.
True...you can't maintain high intensity for as long, but you also burn calories after the activity. For that reason weight lifting is also a good way to help with weight loss. Intervals also burn a ton of calories. You don't need LSD to lose weight. Most of us don't have 3+ hours a day to dedicate to cycling so we have to make do with higher intensity for a shorter time.
 

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not quite cal in = cal out

your body fat, as an energy source, is not equivalent to a gas tank - it is not drawing straight out of tank per unit of energy demanded by the accelerator.

it is more like monthly budget plus savings, with the portion of savings being at some level to accomodate the ebb and flow of money in the month-to-month expenses.

when you exercise 'moderately' as the studies say: 3-5 times epr week, at least 20 minutes, and at 60-80% max HR, all other things being equal such as calories IN, your body will eventually make a hormone adjustment to maintain a certain level of body fat.

this is the key: continued, sustained behavior drives your body's judgment of what level of body fat to retain.

if you do high-intensity activity, you typically can't hit the 20-minute mark, and less likely to hit tht mark 3x/week. cumulatively, you will expend the calories as energy, but it has not been done in the style, mentioned above, that will drive the hormone adjustment to the lower body fat set point.

you can do high-intensity and carry higher levels of body fat. there are many athletes ,pro and amateur, who expend a great deal of energy, such as lifting a LOT of weight, but who have a good amount of fat on their body. losing body fat does not help you clean and jerk more weight. competitive bodybuilders cannot merely lift more to be 'cut' for competition. they have to also figure out a diet, and sustained moderate aerobic exercise, to set their body's level of fat to retain.

look around at workers buring high energy all day: construction workers, grocery stockers, etc. these guys are rarely lean. their bodies can do the work without resetting the fat reserves level.

in your neighborhood, you can see guys playing pickup basketball, soccer, or ultimate. frisbee regularly. their heart rates do not stay up at the 60-80% of max for 20 minutes or more. HR goes way up, then back down after a few seconds to a couple minutes of moderate or hard activity. so, you look on the bbal court, or the soccer field or ultimate field, and you can see players who are not at low body fat levels. in fact, you can see some guys playing really well, and hustling a lot, carrying a beer belly and other body fat. yet they re expending the energy, according to the cal in = cal out theory.

when you start working out moderate intensity 3+ times a week, 20 minutes or more each time, then you will recalibrate the hormone-determined set-point for fat reserve.

**
i have heard this explanation: our bodies evolved while we had a lifestyle that occasionally required migration. fruit ripens here, grain ripens there, animals migrate, disease breaks out, floods come, etc. 'we' always had to do occasional migrations. imagine some cave men migrating: walking a couple hours per day at moderate levels of activity, carrying babies and stuff. food is available, so fat reserves are not necessary. but lower weight helps the efficiency. then, settle down for the winter, store up some fat, and take it easy.

the body can recalibrate to different fat levels.

this also explains why people who exercise moderately 3xwk+ for 20 min +, but who do not eat enough, or do not eat meals speard out cross the day, may lose some weight, but will hit a plateau, and not lose more - the eating pattern indicates that food is NOT reliably available. I have seen this clinically, and seen people's weight loss trend resume once they get back up to 200 cal.day or 2200 cal / day, spread the meals around versus once per day, and maintain exercise. their bodies recalibrate to the apparent conditions.

i have seen this explanation presented in a couple places, but have not really seen the hormone science spelled out too directly and clearly. i have been noting articles on this across time, and one day i will write it up.
 

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just eat less and ride. i dont eat before my morning ride... if im doing less than 50 miles for the ride ill go really hard to compensate. on say an 85 mile ride ill avg 15-16mph. its been working so far for me. that and all I drink is water each day. when im on the bike I do one bottle of water and one bottle of cytomax
 

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mrfizzy said:
I think you have it all wrong here, its called aerobic (ie utilizing oxygen). Aerobic metabolism requires fat to enter to metabolic cycle.
High Intensity Exercise does use a lot of anaerobic (carbs) for fuel, but at best after less than a minute, a trained person is still using aerobic metabolism for energy.

At rest your bodie's main fuel source is fat almost exclusively.
You're mistaken. The end product of glycolysis is pyruvate which is oxidized in the mitochondria, if pyruvate is being produced faster than it can enter the mitochondria and be oxidized than lactate forms. Anaerobic vs. aerobic don't have anything to do with carbs vs. fats per se, and really are unfortunate terms for mammalian physiology (I believe they originally come from yeast physiology). We are never truly anaerobic during exercise.

You're right fat is the main fuel source at rest and then you rely increasingly on carbs as work rate increases. Somewhere around your lactate thrshold your working muscles are relying almost exclusively on carbs, certainly if you're excercising above that intensity (e.g. at VO2max intensity).
 

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this probably doesn't address the op's question, but it's amazing how being out on the bike will tire you and burn calories. One of the hardest rides I've done in recent memory was with some guys from work. After we got about 20 miles, they wanted to stop constantly. It took us 4 hours to do 40 miles. That just wiped me out, it takes a lot of energy to get going again.
 

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slow = more time on bike

The whole point about riding slow to burn more fat is that if you ride slow, you can ride longer, more often, etc. Riding longer burns more calories, and more fat.

I might be able to ride 200 miles at 20 mph. I can only ride less than an hour at 25 mph. So, which would burn more calories? I can ride long every day, even twice a day, at 15 mph. Turn the wick up to 28 mph intervals, and I'm a mess and need recovery for several days. Riding slower allows you to ride more.

I have never heard that for a given amount of time, let's say 2 hours, riding that 2 hours slower will burn more fat. If you have limited amounts of time, or are not limited by recovery (can repeat daily), then by all means riding faster will burn more calories and result in more weight loss, given the same intake.
 

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Getting precise

Fixed said:
I might be able to ride 200 miles at 20 mph. I can only ride less than an hour at 25 mph. So, which would burn more calories?
Curious that you would choose those two numbers, because the hourly burn rate for 25 mph is just about double that for 20 mph. Obviously 10 hours burns a lot of calories. Few people (except those on this forum :)) can ride 25 mph for 5 hours, that's for sure!
 

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While it's good to throw in some low intensity training in with a workout regime, people take the low intensity thing as an excuse for laziness.

I see it all the time: very overweight people on a treadmill walking at the same pace they would walk around the block to stay in the "fat burning zone". They do their 20 min a day 3x a week and that's it. They are not burning many calories doing this and hence stay overweight.
 

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real data

Kerry Irons said:
Curious that you would choose those two numbers, because the hourly burn rate for 25 mph is just about double that for 20 mph. Obviously 10 hours burns a lot of calories. Few people (except those on this forum :)) can ride 25 mph for 5 hours, that's for sure!
Riding 25 mph is about 270 watts for me. Riding 20 mph is about 180. Amazing what happens when you have real data. Does calories burned correlate closely with power output? I would speculate that you're much more efficient at lower power levels.
 

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Fixed said:
Riding 25 mph is about 270 watts for me. Riding 20 mph is about 180. Amazing what happens when you have real data. Does calories burned correlate closely with power output? I would speculate that you're much more efficient at lower power levels.
:eek: Wow you must have a crazy Cda, is that on a road bike?
 
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