To bonk or not to bonk....

on 11/10/17 6:24 pm
RNY on 05/19/17

Happy start of the weekend! Since the best days of the week for play are now upon us, I have a question for all of you RNY athletes - how do you manage food so you don't bonk when exercising? I'm really having a difficult time with that.

I chose my surgeon because he is a triathlete and has had a number of patients get back to marathoning, pro-rollerblading and the like. Right up until I couldn't, I was a very serious road cyclist. Now when I ride I find I'm absolutely fine for about 1 1/2 hours, then I bonk. Hard. Like nearly falling off the bike and sitting on the side of the road in tears because I don't have the strength to finish the last 1/2mile to the car.

I tried using a protein shake for support mid-ride. It held off a hard bonk, but I still felt pretty lousy. (Mind you, these are still really short rides - 12 to 15 miles or so. Nothing like the 40-60 mile daily rides my friends are still doing. We live in PA so it's quite hilly in every direction.)

I asked the nurse at my recent check-up. Her comment was that the patients who had returned to full athleticism had all had the sleeve instead of the RNY - which was extremely discouraging to me. She also advised using sugar-free applesauce packets about every 15 minutes for carb boosts. I haven't had a chance to test that yet. It sounds like a good plan though I have some doubts. So anyway, since several of you have so obviously conquered this bug-a-boo I thought I'd ask someone who has been where I want to be.

Thanks in advance -


62 year old woman, surgery 5/19/2017 - HW - 345, CW - 139, GW - 160ish (BMI based healthy weight - 140)

on 11/10/17 7:52 pm, edited 11/10/17 11:52 am
RNY on 07/23/14

Hey! Good for you for getting back to what you love.

I don?t do long distance endurance training but do train hard. I know you are early out, so not sure what you can handle pouch-wise but I would not use applesauce.

I would absolutely carry food with me... Possibly a protein bar. You can eat the whole thing or a piece of one... depending how much you need. Yes you need some carbs, but if there isn?t some balance with protein and fats you could be setting yourself up for possible dumping or blood sugar crashing.

Question really is what are you eating before you leave for your ride? And how soon before?

Also what time frame are we talking until you crash physically on your ride?

I can?t say I know all the ins and outs of blood sugar and exercise, but dealing with my own hypoglycemia I know blood sugar peaks about one hour after food. That is why ideally you should eat 45-60 minutes prior to going out. BS starts to come down and back to normal by 2 hours...

I asked those questions because you kind of need to create your own timeline to see what?s happening and then figure out a timeline that works. I think every 15 minutes is probably excessive..

Edit: There are people on here who do marathons and triathlons so hopefully someone will chime in.

Cynthia 5'11" RNY 7/23/2014

Maintaining a 220lb Weight Loss
Plastic Surgery Dr. Joseph Michaels - LBL and Hernia Repair 2/29/16, Arm Lift, BL, 5/2/16, Leg Lift 7/25/16

Need to get back to Basics? The Five Day Meat Test



on 11/11/17 7:16 pm
RNY on 05/19/17

Thanks NYMom. This is really helpful. I have no doubt that it's going to take me some time to figure this out, but outside wisdom is a true boon. To answer your question, we usually ride pretty much right after breakfast - so by the time I get on the bike it is probably right around an hour after food. So far, the longest I've been able to pedal has been 1.5 hours before I crash.

I'll try to incorporate cut up bars into my training and see how that goes. That sounds like a great suggestion. The biggest problem with eating solids is of course that I can't hydrate properly if I have to wait a half hour after solid food. I think that was part of the nurse's reasoning when she suggested the applesauce. I can drink more quickly with that than I could with a bar. (As I said in the original post, I tried putting protein shake in one water bottle, hoping to marry both the protein and liquid. It did hold off a hard bonk, but I still felt pretty crummy after the 1.5 hour mark.)

You've given me a lot to think about and a new idea to try. Thank you!

62 year old woman, surgery 5/19/2017 - HW - 345, CW - 139, GW - 160ish (BMI based healthy weight - 140)

on 11/11/17 7:29 pm
RNY on 07/27/17

Also try protein waters. Shakes (full liquid) make me sick to my stomach if try to drink them mid-workout, but clear protein doesn't bother me. Bariatric Choice makes protein syrups to add to water that I use with a dash of Crystal Light. (Ymmv--sour flavors are REALLY sour since surgery and I rely on Crystal Light!!)

on 11/11/17 6:07 am - Philadelphia, PA
RNY on 04/28/15

I wasn't at 'full athleticism' pre op, but like to think I am there post op-- and I'm an RNY. I'm not a triathlete or a marathoner, but I do run and workout regularly, 1-1.5 hours. I also live in PA. I've never had an instance of feeling like I was going to bonk out. I've never felt the need to bring any kind of nourishment on a run. I do conciously eat a higher level of carbs before my run days, to make sure the stores are in my system to be drawn from. That's as much as I feel I need to do.

I do have bouts of reactive hypoglycemia, but they haven't occurred in connection with exercise.

5'6.5" High weight:337 Lowest weight:193/31 BMI: Goal: 195-205/31-32 BMI

on 11/11/17 7:23 pm
RNY on 05/19/17

Oh Ms. Peach, you have no idea how lucky you are if you can do all of that without the angst of a bonk! I'm decidedly envious!! I only ever bonked once prior to surgery and that was on a 60 mile ride with no rest stop for refueling, with nothing bu****er in my bottles. I got back about a mile from the car and wound up just lying on my back under a big ol' sycamore tree. Drinking water didn't do a thing. I simply was incapable of making the pedals go 'round. I didn't even have the strength to walk that one silly mile. It was pretty grim.

Since surgery I've bonked nearly every time I've ridden - all at about the 1.5 hour mark. These have been really hard bonks, too. They've made the one pre-surgery (years before surgery) look like a tea party.


62 year old woman, surgery 5/19/2017 - HW - 345, CW - 139, GW - 160ish (BMI based healthy weight - 140)

on 11/11/17 8:15 pm
RNY on 07/23/14

Realize too you are still pretty early out from surgery so I am sure your calorie count is still low. Even in my honeymoon losing phase I always had about a 200 calorie spread depending on the day. So heavy exercise days may need to be at the higher end.

While you are not supposed to drink for 30 minutes in general... you can drink right up until you eat as well as if you need to take a few sips before the 30 minutes are up it's not the end of the world... you aren't going to hurt yourself.

If you are 'bonking' at the 90 minute mark, you probably need to eat something about an hour in.

Cynthia 5'11" RNY 7/23/2014

Maintaining a 220lb Weight Loss
Plastic Surgery Dr. Joseph Michaels - LBL and Hernia Repair 2/29/16, Arm Lift, BL, 5/2/16, Leg Lift 7/25/16

Need to get back to Basics? The Five Day Meat Test



on 11/11/17 6:48 am
RNY on 03/20/17

I really thought "bonking" was a euphemism for something else. I was like "Bonk! Everyday if you can!"

I'm still not even sure what exactly it is.

on 11/11/17 10:14 am
RNY on 02/15/18

Came here under the same assumption and was going to give my enthusiastic pro-bonking support.

HW: 340 SW: 329 Goal: 150

CW: 265

Surgeon: Dr. Kalyana Nandipati (Omaha, NE)

on 11/11/17 1:44 pm

I thought exactly the same thing!

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