Burning Fat vs Carbs

Hi there. I've recently started cycling again, and have the following two goals for my training:

1) Improve cycling performance and reduce body fat
2) Build (upper body) muscle

The problem I have is balancing the two above goals in my training as in some respects the two are contradictory.

I have read that at a low exercise intensity, I think L1 or L2, the majority of calories burnt come from body fat, and at increasing intensity (eg L3 / L4) an increasing proportion of calories burnt come from food.

My question is, firstly, why does the body use fat for energy at all, given that there is sufficient carbs floating around it can burn, when fat is supposedly
the second choice energy source? Am I going to be losing fat as a natural result of aerobic exercise, even if I don't lose weight overall?

Also, since I have generous stores of fat around my waist, need I worry about the body consuming muscle protein if I max the cycling training, since in theory it should use the fat stored ahead of this? i.e. will I still be able to build muscle?

Hope this makes sense!

Gary.

Fat is used first. Fat burns at a baseline contunuum. But it burns slowly so any harder workouts burn carbohydrates in addition to fat.

When I began cycling again every ride was a time trial. I just rode as hard as I could based on the distance I wanted to cover in the time I had. My cycling seemed to get better very quickly but I didn't seem to loose much around the waist. I read what I could, learned at what effort the fat was burned, and started riding at that level. I dropped all the excess around the waist very soon after. I stll don't know if it was gonna come off anyway, but it seemed to happen when I spent more time at a fat burning level. Regarding muscle protein, you won't burn muscle protein if you train smart and eat right. I think it would take a very high level of painful cycling and poor eating habits to "burn" muscle. You will gain upper body strength and size if you tailor your training for that purpose.

If you want to lose fat and build upper body, then you'd be best off splitting between cycling and upper body weight training. Building muscle helps burn fat. In cycling we generally shy away from building extra muscle because it adds extra weight. I'm sure you intended to do that though you didn't mention it.

In cycling, I believe you'll burn more fat with more intense exercise than at L1/L2. Percentages of fuels used are not indicative of amount of fuels used. For example, at L1 you may burn 80 arbitrary units of fat and 20 of carbs giving you a ratio of 80% to 20%. While at L4 you'll burn 120 units of fat and 360 of carbs giving you a ratio of 25% to 75%. Smaller percentage, but more fat used.

I'm not an exercise physiologist, but I believe my simplistic explanation is correct. Otherwise, someone will correct me soon enough.

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JFTR though, when you start to burn muscle your perspiration stinks of ammonia. A very clear, unmistakable smell, not just a hint of what might subjectively be called ammonia-like. But you have to ride like this:

For a given amount of time, the more intense the exercise, the more fat you will burn. Low intensity does not burn more fat calories. It burns a (slightly) higher percentage of fat, but in absolute numbers it burns fewer calories of fat.

How do you think Ullrich got in shape after all that schnitzel? By walking around Switzerland Looking for Edelweiss??

I always thought it was the other way around? ie: the body chose to burn carbs which is a readily available energy source, rather than processing the stored energy of fat?

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Fitness is as way of life that rewards you with good health.

The body burns both all the time. Just the ratio is altered depending on how far you go.

We can only burn so much fat. Increasing the amount of work only increases the amount of carbohydrates.

http://www.cobr.co.uk/e-cobr_informa...0sources.shtml

I wouldn't have thought cycling was the best way to build upper body muscle.

That's a topic of a different thread. The question is whether low intensity exercise burn more TOTAL fat than higher intensity. It does not.

Not exactly - I wanted to know why fat was burnt at all when there were carbs available, having been led to believe that the priority of the body was carbs, fat, protein, with no mixing of sources if the favoured source were present, so that I could understand how I could tailor my training to lose fat and build muscle; but the general concensus of opinion is that fat will be burnt regardless of the intensity of the exercise. Hence when cycling I will train at the intensity needed to improve my cycling, rather than with the aim of losing fat in mind.

In reply to another post I'm not doing the cycling to build muscle, I am doing weight training for that, I'm doing the cycling to get fit... and also because I love it!

Thanks for the replies.

Another important thing to remember is along with getting exercise you really need to ensure you are on a good healthy diet. If your diet is all screwed up then you really aren't going to be getting all the benefit of the exercise.
The best thing you can do is start keeping a log of everything you eat and drink including water. Ensure you measure your food and then you can keep track of the calories you are eating. I have been a personal trainer for 10 years and it always makes me laugh when I show people what makes up a serving for a particular food. Most people are always suprised when they find out the actual calories they are consuming in a day. Try and stay away from all the wonderful, crazy diets out there and instead just focus on eating a healthy, well-rounded diet.

I'll put it into simpler terms...burning fat is like burning a candle, it takes longer to get rid of and burns slowly. Burning carbs on the other hand is like burning tissue, it burns fast but creates a lot of heat (energy)



You could just not eat anything for...say a week and train intensley on all of those days, that way you could burn alot of fat!

forgive me if screw this up, but here is my understanding:

and just like a candle, burning fat requires oxygen. that is why it is generally at lower intenisities that most fat is burned. if you run a test on a trainer with a gas anayzer mask you can actually see that as you begin to go anaerobic your fat burn will trickle down to zero.