How do you know if you've changed from burning carbs to fat?

Hi all, still new at this and love the support so far! My question is kinda strange, but is there a time when you begin to notice that you're burning fat for fuel instead of carbs? I ask this because recently after workouts I've had an accelerated heart rate that lasts a couple hours. It's feels like I've had a double expresso, or like I'm anxious or nervous. This has happened both after a 5 mile bike ride and after 25 min of HIIT. And today it happened at a very odd time, after breakfast. I checked my heart rate and it was about 90bpm while standing and maybe 75-80 sitting, which is still in the normal range. It will go down after a couple of hours or after I eat. Has this happened to you? Am I getting more sensitive to caffeine (which may explain the jitters this morning). Does this have anything to do with eating reduced carbs (<100g)?

Replies

justaspoonfulofsugar

the main thing I notice when I am in a ketogenic state (fat burning mode)is a very bad urine smell,which is ammonia like.Also,there is a death breathe that can come as well.
As for feeling shaky and hyped I would think it would be caffeine sensitivity.
I know that when I am in ketosis,I am SUPER caffeine sensitive.I can't have coffee on workout days and I feel like my heart could come out of my chest.It makes me feel pukey.
How long have u been eating low carbs?
I can't get into ketosis unless I am under 50 grams per day and when I started it took 2-3 weeks to get into fat burning mode.

EchoDelta1013

With a reduced carb intake and the anxious or nervousness you're getting, you may have developed a case of hypoglycemia. This is defined as having a low amount of glucose (sugar) in your blood. Symptoms include: shakiness, light-headed, dizziness, & a fast heart rate to name a few. As a diabetic, I know of hypoglycemia well. But you don't have to be diabetic in order to have it. If you have access to a blood sugar tester, you can check you blood when you have a fast heart rate. If not, try eating fruit to see if it helps. You could also see a doctor because there may be some other underlying condition

ahviendha

With a reduced carb intake and the anxious or nervousness you're getting, you may have developed a case of hypoglycemia. This is defined as having a low amount of glucose (sugar) in your blood. Symptoms include: shakiness, light-headed, dizziness, & a fast heart rate to name a few. As a diabetic, I know of hypoglycemia well. But you don't have to be diabetic in order to have it. If you have access to a blood sugar tester, you can check you blood when you have a fast heart rate. If not, try eating fruit to see if it helps. You could also see a doctor because there may be some other underlying condition

this is interesting to me. i have hypoglycemia, which is why you can see my breakfasts are always lots of protein and fat.

i think you probably have become more sensitive to caffeine, when i started eating better i became more sensitive to smells, taste (i cant stand salty food now!!) and stimulants. even a half cup of weakly brewed coffee gets me raring to go! i usually just have black tea.

are you practiced in calming yourself? sometimes a couple deep breaths, four counts of drawing in breath, four counts of drawing out breath can slow your heart rate. works for me when im stressed!

iconnor

Hey, thanks everyone for your input! I added half an apple for breakfast, so far so good, but haven't worked out yet, so we'll see. I've been really good about not having any refined sugars the past few weeks (dark chocolate here and there) and have been trying hard these last two weeks esp to stay under 100g carbs. I also started HIIT two weeks ago too, so maybe that's contributing to this feeling as well.

I think maybe I need to rethink coffee, or maybe less strong coffee on my workout days, or not having it so close to my workouts.

I'll also look into some yoga/meditation, I used to do it in the past but am now out of practice. Thanks again for your two cents.

fitnessbugg

Maybe you could do metabolic testing? I had metabolic testing done at the gym. The whole point was to find out when you are burning mostly carbs for fuel. You have to run on a treadmill with a mask. It was pretty uncomfortable. Because of paleo, I almost had to give up before I could get to the point of burning carbs! The trainer said it was excellent. He doesn't see it very often, especially in women my age!

ngyoung

If you get those urine ketone strips you should see them turn purple when your body is just starting to ramp up your ketones. That means it has begun making them more but not really using the since they are in your urine. It should then start going back to a lower color amount when your body is actually starting to fuel itself off of your ketones instead of expelling them in your urine.

You could get a blood ketone meter but the strips are like $50 for 10 strips.

Joydriven

The lick and sniff test works well. Just lick the back of your hand, let dry and sniff. If it's pretty yucky, yup, ketosis.i bought the strips but this is so much easier.

iconnor

Thanks again, everyone! I believe it is due to caffeine sensitivity. I may need to make half-caff coffee from now on, or switch to tea, although I know some teas have just as much and sometimes more caffeine than coffee.

The ketone strips and metabolic testing sound like good ideas, although right now I'm a poor grad student right now on a limited budget! May need to stick with the pee/lick tests (albeit not together lol) for now.

With regard to the fat burning, would it be better if I brought my carbs down to 50g/day if I can manage it? I just finished reading about runners who have switched to low carb, high fat, and have found that they do better on their runs, have less stomach issues, and don't need to refuel during their runs. I am intrigued by this...

TriLifter

With regard to the fat burning, would it be better if I brought my carbs down to 50g/day if I can manage it? I just finished reading about runners who have switched to low carb, high fat, and have found that they do better on their runs, have less stomach issues, and don't need to refuel during their runs. I am intrigued by this...

Where did you read about that? Would love to check it out.

I was primal, but am doing a Whole30 right now and am practically dying. The day before I starte I ran 13 miles at 8:48 pace, now I can barely run 3 miles at 9:30 pace without feeling like I'm dying!

iconnor

http://www.meandmydiabetes.com/2012/08/11/western-states-100-low-carber-wins-ultramarathon-steve-phinney-and-jeff-volek-study/

It's about ultramarathoners, but the guy being interviewed is arguing that fat provides more energy than carbs.