Bloodwork issues due to carbs?

Hi all,

Recently had bloodwork done and my triglycerides (272), ALT (61) and AST (44) were all elevated to unhealthy levels. That said, I usually do about 60g/hr of carbs while riding 3-4 times a week for ~ 4-5 hours total. VO2 max is 52 (per Garmin) and my w/kg is about 2.9. I have a pretty healthy diet so this was surprising (5’10", 175lbs).

Has anyone else experienced this? Did you end up cutting back or cutting out carbs while riding? Appreciate any insight here.

Edit: waiting to hear back from my doctor as her default response was to lower my fat and cholesterol intake. I responded back about the cycling carb loading and hopefully will get an answer soon.



What does your doc say to these questions?


What does your diet look like off the bike?
I ride 9-12 hours per week, with 75-90g of carbs an hours (yes even endurance rides).
Have never had any issues with bloodwork, although I’m do for one soon.
End of the day, what does your doctor say?

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This is probably not universally agreed upon, but if your rides are one hour in duration, you don’t need 60g of carbs. You don’t really need any carbs. Your body should have plenty onboard for an hour, even 90 minutes. If you are worried about it, cut it out and see how the rides go.


Yes. I had already started cutting out carbs for Z2 altogether. My thought was to take them in to make sure that I could continue processing them … I am going to drop them way down even for 90 min threshold rides as well.


Eating 300g/wk of simple carbs is not going to significantly affect your bloodwork in anyway.

How often do you drink alcohol? I also see that you’ve mentioned previously that you take Skyrizi - this drug can cause the bloodwork abnormalities you mention… as do many other drugs. Drugs/alcohol would typically be the most common causes of something like this.

As other have said, this is something to speak to your doctor about.

Conversely though, if your workout are only an hour, there’s really no reason to eat carbs during them… rather than just eat before and after.


Thanks. Yea, I didn’t actually pull the trigger on Skyrizi. I hardly drink at all (a few drinks a year). I don’t do any other drugs other then … drum roll, a SSRI. I was more looking for anecdotal accounts and if anyone else ran into this and how they dealt with it. I found some older threads where someone did have a similar issue.

Did you have any muscle soreness at the time of blood draw?
My liver numbers looked terrible at my physical but were normal on followup.
I was really sore fro strength training 2 days before. Chalking it up to that. Muscular exercise can cause highly pathological liver function tests in healthy men - PMC

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Virtually zero chance that your lipids and liver enzymes would be elevated from taking on 60g carbs per hour while on the bike.


My understanding is that triglycerides are formed when there are excess calories ingested. The liver converts the sugars and fat into triglycerides that will then be stored by the body.
Triglycerides can spike after an heavy meal (or lots of sugar not consumed or stored by the muscles), which can influence bloodworks

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Appreciate all the input folks. I will talk to my doctor further. Certainly not looking for medical advice here just looking for any folks who may have had issues with this. I’m at the tail end of a 3 week virus coughing up junk. So the blood work on top of that has been kind of a bummer. Going to get back into training tomorrow finally. Going to keep my carbs down on the shorter rides. I’m going to get retested in another few months.

Yeah I’m just looking for a reason. I really have a pretty healthy diet. I don’t eat or drink anything with a ton of sugar other than the bottles I make for my workouts. I pretty much don’t drink alcohol at all as I stated another post so I’m just trying to figure out what the smoking gun is here. Maybe Thanksgiving pie was more of an issue than I thought ha.


It could also be because of the virus. Drugs or Tylenol can be pretty hard on the liver (or just the virus by itself)

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Not sure what virus it is. Prob not flu or covid. I haven’t taken any Tylenol. Really just vitamins and some NAC. There are a ton of variables here. Could be a fluke. Appreciate the input.

I do seem to recall someone on the forum that went from normal blood numbers to elevated numbers like yours after they started drinking sugar on every hour of every ride.

First, I’d probably retest the numbers just to make sure it wasn’t a lab anomoly. Then maybe try fueling more with food than sugar and then retest again. And yes, discuss it all with your doc.

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From the ALT and AST I’d suggest scaling back on fructose (and booze, if you drink). If you want to continue the 60g/h of carbs during workouts, fine, just make it a glucose only mix. Could be early signs of nafld.

High trigs could be anything. I have heard it said that in research circles, increases in triglycerides are a marker for compliance to higher-carb-diets. Have you made such a diet change? Hopefully you were fasted 12-14 hours for these labs? Recently eatting will definitely raise trigs.

Was there a fasting blood glucose? If you were fasted and fbg was borderline I’d be concerned about your general metabolism. Being a decent endurance athlete is not a guarantee of metabolic health.

A cheap thing I like to suggest is getting a personal glucose meter and strips. Test a bunch for a few weeks. When you wake up. Before and after exercise. Before and 2-4hrs after meals. If you ever see a reading of 180mg/dl you have diabetes coming for you. Generally it shouldn’t be over 140mg/dl.

Disclaimer: not a medical professional but I do like to read and have a personal interest in metabolic syndrome.


Is this your first test with elevated numbers? My guess is your off-bike diet has way too many carbs for your body.

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I hadn’t had my bloodwork done since before covid, so got caught up on my doctor visits this year. I had issues with triglycerides (and LDL, supposedly) for a decade before covid. Also since covid started, I’ve increased my bike riding/“training” consistency to 5-6 days (lots more real z2 days, but usually only 60-90 mins) and also have gotten more consistent with my use of maltodetrin on >1hr, non-2 rides (similar 60ish g/h as OP). My triglycerides were in the 70s both times I had it checked this year (they were typically much closer to 200 previously).

I also did some experimenting with a keto/blood glucose meter I bought a few years ago when I thought Id try keto (didn’t work out to well for me and my ride intensity). I’ve watched some of the Peter Attia videos about metabolism issues, and have been eating straight sugar, and also bingeing on recovery carbs, mostly on the weekends, despite my typical lower carb diet. So, I did some blood glucose testing for a couple different ride days (2-3 hours mostly z3 & z4), checked every hour and before and after meals. I was very pleased that I don’t appear to have any issues with my blood glucose (at this time). Only thing that really spiked over 120 was drinking a coke with some chocolate covered almonds and I was trying to spike it to see how I react. Previously, when I was trying keto diet and targeting using malto on rides) I had one ride that I clearly didn’t eat enough and felt awful when I got home, and got a BG in the low 60s (yeah that’ll do it), and the next ride I apparently over-compensated and got home and had a BG in the 160s (but it cleared up really quickly). Interesting stuff.

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Yes. Haven’t had bloodwork in a year. Previous ALT and ASP were 35 one year ago. Tris, donno. Wasn’t measured for awhile. Time to go strict on the diet. Always easy this time of year /s

I’d get liver markers re-done after 48-72 hours rest. It’s very well established that AST and ALT can be skewed for several days by strenuous exertion. Those numbers are within the realms of that possibility.

I assume the triglyceride test was done fasted (min 12 hours) and 24 hours after any alcohol?

If it were me, I might simply get the tests repeated, and go from there.

Nb - I am not a medic and this isn’t medical advice.