I would never try and be underfueled for workouts. Eat less the rest of the day if you need to lose weight. And you really don't have that much to lose. 5lbs will naturally come off as you increase the duration of your workouts.

Your fueling during long workouts should be viewed as practice for race day. Experiment with different products and see what is the maximum amount of calories you can absorb while putting out a hard effort.

What heart rate zones are you training in? Have you done a LT or FTP test? Perhaps your going to hard and that's why you are bonking. Try slowing it down a bit and see if that helps.

As for fueling, look into Generation UCAN. I use it to fuel all my races and "long" endurance training sessions. It helps keep your blood sugars in check.

Makes sense, I really appreciate your input. I have tolerated something like ~1000kcal/hr CarboPro with a Clif Gel added for a touch flavor, but I can experiment with other stuff too. I bet I could do more than that. Certainly I won't try to under-do it race-day, I was thinking more if it make sense to stretch oneself in this way prior to the race, but it sure sounds like I shouldn't let a concern of over-consumption keep me from the best efforts in training. Thanks.

woah there, 1000 cal/hr is waaaaay to much. most people are in the 300-500 cal/hr for IM intensity and 200-400 cal/hr for HIM.

This is a good point and something I haven't thought about. I have done 20 and 40 minute FTP tests on the trainer, and am using the 12 wk Zwift winter plan according to those results. I am able to complete most workouts and I feel the zones generated from there are reasonably close for perceived effort, although my HR is higher in the lower zones by about 15-20bpm. IE, if i set the FTP slider to my tested FTP level, my power Z2 is probably around by HR Z3. I only have power on the smarttrainer so hard to tell that outside for long rides, I try to stick in Z2 for long rides, but I usually ride with a faster rider and excellent climber and sometimes note that I will drift into Z4 on even gentle climbs. Maybe i'm wearing out more than bonking. I'll look into UCAN.

Yeah I figured something was off judging from what people say here. The bottle says 200 cal/scoop. I put down a 5-portion gel flask with about 4 scoops in it (was super thick) in addition to 1.5 scoop Carbopro+1 scoop Gatorade each in 2 20oz bottles in a 2 hour ride recently and FELT AWESOME but I knew it was kind of ridiculous at the same time. Ill try to stick to like 500/hr on the weekend ride and see what happens.

On the other hand if his body can actually process that much and he's not having any gastric issues, then that's awesome. That'd be a great competitive advantage for like an IM.

Probably unnecessary for his 70.3, though, where 300-500/hr should be enough to avoid bonking during the run.

Personally, I've found my bonk-avoidance is largely fitness related, not the result of any specific nutritional protocol. The fitter I am, the farther I can go.

You know, if I am honest with myself I know that's a big part of it. The duration of these is whats getting me - I don't want to mislabel my (improving) fitness for bonk. Sounds like training is the answer for that.

Somewhat related, but I got into a convo with another swimmer-turned-triathlete about this recently. If you think about it, all pool events (even up to most "long" races, which really top out at 1500M/1650 at most club levels) all race considerably less then 30 min duration. Swimmers are really geared for threshold/anaerobic efforts. Obviously you need to learn the other disciplines, but in regards to cardiovascular fitness, maybe going from swimming to tri its just so much more about about extending the duration of effort rather than boosting up the lactate threshold/FTP/pace etc. This is in comparison to the grand fondo roadie cyclist-turned-triathlete or marathoner->triathlete who has experienced events of much similar duration.

Yup. You are relying far too much on fuel. You can easily cut your intake in half or a third of what you are doing and it should improve your health as well. And you are correct on the swimming to triathlon problem. Swimmers are trained to dump every ounce of energy out of their body as fast as possible. In longer stuff like triathlons, you can touch those efforts in training, but you want to avoid them like the plague on race day until you can hear the cheering of the finish line coming. Except at Ironman Canada where those buttheads make the run course go near the finish line several times but then turn it away over and over again. Damn them. Damn them all to hell. ;)

On a separate note, I found that breaking myself of the sugar habit was helped by letting myself bonk on a run, but not quitting and just walk. After about 20 minutes, you recover and can start jogging again. I think what's happening is you are firing up the fat burning metabolism that's been cold and dusty for months or years. You'll be able to run just fine, just gotta be patient. And then on your next run, you'll notice it takes about 15 or 20 more minutes before you bonk and also your bonk will be far less severe. Keep repeating this and you'll be "bonk proof" off sorts in just a couple of weeks. Yeah, you'll feel a low point, but your fat burning systems will be good to go and your dependency on sugar not as bad, so you can just slow down a bit and feel better at hour 3 instead of needing to sit down or walk at 30 minutes in.

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Zen and the Art of Triathlon. Strava Workout Log
Interviews with Chris McCormack, Helle Frederikson, Angela Naeth, and many more.
http://www.zentriathlon.com

Thanks so much Zen, I'll try it. That's really what I was looking for. Maybe I'll start by cutting out any supplemental calories on my long solo runs (I had been maybe taking 1 gel at one hour, none for shorter runs) and try to run past the bonk as you did. This way I don't flail on the next group ride, but in addition I'll be cutting down a bit there too as others have mentioned.

This. I would say for most people, bonking is lack of fitness rather than poor nutrition. I've done plenty of races without any nutrition, especially when I first started, I was doing OD races with just 1 bottle water, 10km OWS with zero fluids/food etc not ideal but if you're fit, poor nutrition will mean slightly slower as opposed to walking half the run course.

Just remember that what other people are saying is also true. Doing workouts on low or no fuel makes for shitty workouts. But your case is the exception where your sugar dependency is so high, you need to break yourself by forcing the situation a few times to reset your metabolism to a more normal level.

You might hear about the magic of occasional short-term fasting. People won’t eat for 8 to 12 hours to burn off their spare glycogen so they can get into ketosis. But you can burn through your spare glycogen and get the same effect in 90 minutes by running.

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Zen and the Art of Triathlon. Strava Workout Log
Interviews with Chris McCormack, Helle Frederikson, Angela Naeth, and many more.
http://www.zentriathlon.com

I'm a former swimmer myself with running being my weakest leg also. I completely agree about swimming being anaerobically focused. What makes you think you are actually bonking and not just fatiguing from reaching your tolerance in training? Bonking is a pretty severe state that implies you can't do anything more without the addition of sugar to your body. Perhaps your tolerance to longer workouts isn't really great and that you are experiencing mental limitations along with a decrease in physical performance. Toughing it out for several weeks may show that your nutrition is fine and your body will readily adapt to longer training.

So, you want him to burn away all available sugar so that the brain is feeding on, well, nothing? And do that a few times? Seriously?

I know people like to throw around the term 'bonk' loosely, that anytime they feel super tired or maybe a little faint...it counts as some badge of honor. If that's all both of you are referring to...great, I guess.

However, a true bonk is not anything you should ever want. Hypoglycemia is bad. It is dangerous. Stumbling around, your brain is fully taxed just keeping balance...that is not healthy.



To the OP, be smart and ease into any big changes. You can break sugar dependency safely for some pretty long workouts. Don't try to crash reset your metabolism that you have been training for years/decades with rash advice from some forum.

People must have different definitions of Bonking...
When I Bonk there is no way I'd be able to run or jog again in 20 minutes. In fact I'd barely be able to walk a mile and not wander all over the sidewalk. I recently experienced this, it was cold outside and I was concerned.

Yeah, the feeling i'm getting is more hungry/shaky/mild hypoglycemia feeling with a notable drop off in speed for a relatively stable effort level in training, clearly not "the wall" bonk. Maybe I should have called it something else, my apologies. In regards to an above comment, I suspected it was more likely biochemical rather than psychological weakness since I seem avoid all those symptoms with the heavy carb intake. With that sugar crutch I can go for 3+ hours much more comfortably, but I admit I could be comfabulating that and improving fitness since I have been focusing on extending the efforts at the same time. Mostly, I am a believer of the outlier-isnt-necessarily-good mantra (a common ST theme) and could tell my intake was high, so seemed like an area to ask for help and make this thread in the first place. Experimenting with less on longer training running first doesn't seem overly drastic.

Thanks everyone, given me a lot of food for thought.

Yes, I'm talking about the exact same thing. Shaky, tunnel vision, super weak. And you didn't die when you bonked, so you can actually walk after you sit for a few minutes. You think that you can't, but you can (obviously, or you'd still be there and dead). And this highlights my whole point. If you bonk that severely, then you are far too sugar-dependent. So let it happen once, then next workout, do the exact same thing and you'll notice that you bonk later and less severely. This is because you are more metabolically flexible now.

It's the exact same thing as when people have to not eat for 12 hours before a medical test. If they are super sugar-dependent, they feel like they are going to die, get all shaky, and feel super weak. But that sensation eventually passes and then they suddenly aren't as hungry anymore. That's the fat-burning metabolism finally kicking in. They "bonked", it just took longer because they weren't burning through carbs by running. The carb burning druggie urge had to go through some cold turkey thrashing before it gave up the ghost. But if you aren't that sugar dependent, not eating for 12 hours to prep for a test is only mildly uncomfortable for a very short while and then you are fine.

You can go from the former to the latter in just a few workouts by bonking on purpose, taking a short break and not eating any sugar, and then continuing at a very easy pace. If the first time you do it you feel like death, that just means you needed it even more. Then your next workout, you'll notice the bonk is later and less severe. And then by the third to fifth time, there's just no point to it because you barely notice it and you're fixed.

Since this doesn't really help you have an awesome single workout, it's not something to do often once you've fixed yourself. But if you do it once every couple of weeks or so, it should help keep your metabolism in check.

I'm not going to argue about it on a forum with people that haven't done it. So if you want to argue about it, try it first. Run in the morning with no breakfast or food of any kind, run until you bonk, sit down and play on your phone or whatever until you can walk again (10 to 20 minutes does the trick). Walk until you can jog, then jog out the rest of your workout. You'll notice after your workout that you're weirdly not hungry at all. That's because your body switched over. Then the next day, do it again and you'll see that you were able to go an extra 15 minutes or more before you bonked and the bonk wasn't as bad.

Send all payments for fixing your metabolism to Dr. ZenBrett's House of NoBonks, 1800 Fixyoself Ave. SaveMoneyia, 77845. ;)

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Zen and the Art of Triathlon. Strava Workout Log
Interviews with Chris McCormack, Helle Frederikson, Angela Naeth, and many more.
http://www.zentriathlon.com

Ben Greenfield, is that you?

Helllllll nooooo. But seriously.... wanna buy a hologram bracelet? I have a pile of them behind my bottles of structured water.

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Zen and the Art of Triathlon. Strava Workout Log
Interviews with Chris McCormack, Helle Frederikson, Angela Naeth, and many more.
http://www.zentriathlon.com

There was a study this year that looked at short-term carbohydrate manipulation. Personally, I don't think 3 weeks is long enough to adapt to a ketogenic diet, so idk about the validity of the results for that group, but the "train low" group didn't seem to do as well as the normal carb group.

study here: http://onlinelibrary.wiley.com/...0.1113/JP273230/full

Slightly unrelated in terms of carbs, but I've noticed a huge boost when using beet products like beet root juice and the preworkout, PerformElite, instead of my usual cup of coffee. I've noticed I can make it through my training on a bit less carb replenishment during, which has been kind of nice.

I think you may be overdoing the carbs with not enough protein, or even, fat.
Don't know your age but I've found that after 45 yrs or so, the body needs more protein.
Check out KIND bars and Accel Gel (one of the few gels that have protein).

Good luck