bfloyd6969

Let me start by saying that I really don't know much about this, just that I have heard it mentioned here and there. From what I hear, it pretty much consists of say having some morning coffee and going out for a training ride on an empty stomach (other than the coffee that is). I guess the point being that the body will be burning more fat for energy? Is this true and is it a safe way to loose a few unwanted pounds? If the body is burning fat for fuel, are muscles being burned as well? I apologize if this is taboo on the forums here but I just want to know about this. Thanks.

gregf83 

There's nothing wrong with going out for a morning ride with a cup of coffee and there is some evidence that it promotes fat burning but it's not bonk training. You still have plenty of glycogen stored in your muscles, liver and blood after fasting at night.

Whether it's an effective strategy for losing weight, depends on how long and intense your ride is and how much you eat afterwards. Sounds like a good strategy for the fall/winter when you're building a base.

wphamilton

For what it's worth, I never have breakfast before my morning commute. I usually start my weekend rides at 10 or 11, again without eating. Sometimes I reach that bonk point on weekends, usually not. I suspect that this practice doesn't help my fitness any, but I can tell you that it has not resulted in any weight loss.

Tundra_Man 

Most of what people consider a "bonk" is not really a bonk. If you're able to get home without assistance you haven't really bonked, you just got really tired/ran out of energy. A true bonk is something you'll never want to repeat if you ever hit it. https://www.youtube.com/watch?v=MTn1v5TGK_w

That being said, I exercise every morning before I eat breakfast. I just feel better working out on an empty stomach.

iheartbenben

Yeah, this is a bonk for sure. If you could see her muscle cramps it would make you physically ill. I once witnessed a young man's calf ball up nearly under his knee cap, and he was still trying to get up and move.

I've heard bonking exchanged with heat exhaustion/near stroke a lot this summer, and that's fine too.

OP, runner's have preached this to me in CC growing up. Eating half a banana or none at all, and running miles and miles to drop weight isn't unheard of either.

hooligancyclist

I guess the point being that the body will be burning more fat for energy?
-I've heard that at higher intensities you'll be burning the same amount of fat, you're just using the other energy sources in addition to the fat burning when you go harder. My guess is that your glycogen stores will already be somewhat filled from your previous meals the last day(s) and you'll also be using those if you go for not a very long ride.
Is this true and is it a safe way to loose a few unwanted pounds?
-Probably not if you are out there for too long. When you do bonk, your blood sugar levels go very low and it is not good for your system, though it will tolerate it. The real danger in this is that your reaction time, mental awareness, etcetera will all be compromised the further you go without food. This begins to take effect after some time, like maybe 2+ hours. 3+ hours in at a moderate intensity it will be more apparent. You can make some very stupid decisions with very low blood sugar, it is an impairment as is being drunk or sleep deprived. Some people have larger glycogen stores than others, and at lower intensities you do not burn through it as quickly.
If the body is burning fat for fuel, are muscles being burned as well?
-I hear that if you are going for a 4-5 hour ride or more to consume protein. I imagine if you are doing multiple days in a row you will want to take in more protein on the bike, maybe even if it is a bunch of 3 hour rides a day several days in a row. I am not very familiar with the protein biz, better find out from someone else.

bfloyd6969

Thanks for the replies everyone - I understand better.

Noclutch

I do this regularly, that is eat minimally or not at all- often just a canned coffee energy drink- prior to a 2-3 hour ride and only drink very diluted G2 during it. I ride about as hard as I feel comfortable, but that is with sweat pouring off of me and usually 85-105% max HR. While never completely "bonking" to the point of collapse, I do start feeling weak between 2.5 and 3 hrs and know that there is nothing left in the tank and rarely get some cramping, and then throttle back a bit.
My rationale, be it right or wrong, I feel that I am training myself on how to deal with spent energy reserves(ie glycogen, and fat- which I don't have much of to start with)- which is where one inevitably ends up at by the end of a race anyways so I better get used to dealing with it on training days so race day isn't so much different.

dolanp

If I do this I usually use an amino acid mix with my water. Theory being that if your body decides it needs amino acids then you have some free so that it doesn't have to catabolize your muscle proteins as much.

gregf83 

Your rationale is basically wrong. You shouldn't be feeling weak at the end of a race if you've trained and fueled properly. Once you get weak from low blood glucose levels you're just wasting time and not training effectively. Contrary to what people think, you have essentially unlimited fat available for exercise and you should be starting with approx 2000 Cals of stored Glycogen which, combined with on the bike food, is plenty for rides of 5+ hrs.

Noclutch

Thanks for the input gregf83. But who actually finishes a race not feeling weaker than when they started?? That would be leaving alot on the table performance/position wise. That is unless one were seriously sandbagging LOL

Also, how could one differentiate between being "spent" physically and truly hypoglycemic short of using a glucometer?

As a clarification though, I never set out to ride until I'm fading fast, that would be silly indeed! Though it happens when I've lost track of time/distance. I guess my point is that under adverse circumstances or scenarios, running out of fuel happens, and if you've been there you might be able to deal with it out of familiarity and really knowing your limits.

wphamilton

Well if you want to use up the glycogen stores and then burn fat and train in that range aerobically, how else would you go about it? High intensity intervals and then some miles? I don't see how Noclutch's rationale could be wrong, depending on what the objective is.

late

My understanding is that 'bonk training' was just a name.

You don't go out and try and induce a bonk, what you do is ride
on an empty stomach to train your system to deal with extreme
situations better.