I was on a Atkins forum about a year ago, and one of the gentlemen on there was a marathoner, and he ate less than 100g of carb a day. He said that the good thing about it is that, being in ketosis, he never "Hit the wall," which is the point in a marathon where all of the body's carb stores are burned up, and it has to transition into fat burning. Being in ketosis, he was in fat burning the whole race, and never had to make the transition. His times for the race actually improved on the low-carb regimen.

OK, that's just some general info for down the road. In "New Atkins for a New You," they recommend backing off on the exercise (if you're not exercising, don't start, and if you already are, take it easy) for the first 2 weeks, to give your body time to adjust. Then you can ease back into it.

My experience bears that out. Last time around, I didn't even try to exercise until about 4 weeks in (not because I was following directions, but because I was being lazy) and it was no problem. This time around, I got on my elliptical, and told myself that if I went really slowly with no resistance, it would be no big deal. And I was wiped out Wednesday and Thursday night, just physically exhausted. So I've stopped any exercise, and will try to start up again the week after next (that will be after 3 weeks of lo-carb eating). We'll see how that goes.

If you've been eating the low carb longer than 2-3 weeks, I'd recommend backing off a bit, and slowly building back up. Your body will get there, just needs time to make the adjustments.

Hope that helps at least a little! And of course, I'm always open to correction by the long-termers on the site!

Peace,
Tom

Make sure you have enough CALORIES to get through exercise! My MFP calorie goal is 1510 before exercise, and 2000-2200 with exercise included. If I don't have at least 1000 - or even better, 1200 - calories in me before I exercise, I can't get through. I get light-headed and dizzy. It's never been an issue as to how many carbs I have, just calories.

If you do feel sick before you go, then yeah don't go. But try to see if having more calories helps you.

I'm also doing a ketosis diet (though it's not a book/program -- I'm working with a certified nutritionist). I am able to remain in ketosis and eat up to 50 g carbs a day. If I were you, I would try increasing your carb level -- and make sure you're getting at least 1200 calories a day. While getting into ketosis might make you feel a bit tired, after a few days in that state you should experience a high level of energy!

I have heard over and over that weight loss is 80% diet and 20% exercise, so I am trying not to go overboard with the exercising (in the past I did P90 along with other workouts). Once my body acclimates to ketosis, I find I have plenty of energy for 30-60 minutes on the treadmill plus some Jillian Michaels, Brazilian Butt Lift, or other at-home workouts.

I do at least an hour cardio a day (I haven't missed a day since December 26th - before that my exercise was part of my routine, but more sporadic). It's usually all on my elliptical, but sometimes I use my bike. I'm actually on my bike right now, but I plan do also do elliptical later (it's better workout). I don't do anything intense on my bike I just watch my shows, browse the Internet and talk on the phone as I do it. With the elliptical, I can't really do anything other than watch my shows. When I'm following my diet I'm typically between 25-45 net carbs per day with the occasional bad days (like this weekend going into Monday, ugh), but even when I do have a bad day I add additional exercise to do damage control and to be at least under on calories after exercise, though I prefer to be under on calories before exercise. For calorie estimates, I go by what my machines say which is lower than the default MFP estimates on calorie burn. I just make a no excuses, no exception rule for myself that I don't skip a day. Even if I don't feel good I can at least do a slow hour on the bike. Now it's just a routine and I don't ever feel like skipping a day. I usually drink two big glasses of water during that hour time and that also really helps.

Have you tried interval training (HIIT, or sometimes referred to as "Tabata")? That may work better for you than a long, steady state cardio program. I've been sprinting for about 10 minutes total (30 second work/rest intervals) lately and love it. I eat more than 20g carbs most days, but I workout pretty hard (lift heavy weights, train with kettlebells and sprint) and manage to stay low carb. Been doing it since July and it's worked out well.

Very interesing! Back when I was in ketosis, I had absolutely no problems with energy. It's just the first few weeks you feel a little rough, due to the switch in fuels your body is using for energy. I plan to keep working out through the beginning phase of ketosis, just less intensely. I have been exercising continuously for the last year, though. Further proof that you can't out-exercise a bad diet! If all the cardio I've done really worked, I'd be a stick by now!