Here's my story: I started running ~3.5 years ago, and it has become something I love. I've trained for a couple of distance races, but for the most part I'm happy as a 20-25 mi/week girl. I don't push it particularly hard, I just enjoy getting out and feeling the ground under my feet.
I've been eating paleo for two months and so far I really, really like the way it makes me feel. I didn't realize how much the blood sugar roller coaster affected me until I got off of it. I haven't been purposefully low-carb, but in my efforts to stay low-glycemic-index, I haven't been loading up on the fruit and sweet potatoes. Unfortunately, I've had to drop running, because my energy level was just. Not. There. I read "Paleo Diet for Athletes" when I was first starting out, but I assumed it wasn't relevant to me because I'm looking to jog around my neighborhood, not complete an Ironman. But now I'm reconsidering.
I'm working on adding sweet potatoes and fruit back in; and I'm also really curious what other runners' (or cyclists', or swimmers') experiences have been on paleo. Did you need time to adapt to the diet before your performance was normal again? Do you purposefully add carbs, or do your cravings guide you appropriately?
(Please, no admonitions about "chronic cardio." Even if I didn't believe that humans are born to run, it's an activity that I love and that makes me happy.)
As a runner with 36 years and almost 550 race experiences (30 years pre-paleo and 5 post-paleo) and as a sports-chiropractor who has worked with hundred of runners, I can assure you that "going Paleo" (if done correctly) has almost zero chance of prohibiting you from casually enjoying jogging 20-25 miles per week (if you were doing that prior) and has a very high-chance of substantially improving your ability to enjoy running in the casual manner that mention.
Personally, my exercise regimen may be similar to yours in that it includes some running/jogging wherein I am 'goofing around' with easy jogging 3x per week and one mixed speed or hill or fart-lik workout per week. Personally I can race a 5km just as fast now 'post-paleo' as I did 5 years ago 'pre-paleo' and I do it on about 18 miles per week vs. 26 miles per week pre-paleo.
Generally, I agree with Anthony in that your body was likely transitioning metabolically and that you just need to hang in there, put your running shoes on and get out the door and eventually you will start to feel better. For me, there was an early-paleo phase where I didn't really feel that comfy running it was like my legs did not feel "fueled", they felt flat..but, then the bounce and desire came back after several months.
Lastly, because you do not list specific details, there could be some tremendously-important factors at play that you are not listing such as : -you take meds -your version of 'Paleo" is an 'outlier' version (we have all seen some pretty ridiculous diets honestly described as 'Paleo') -the general quality of your food is poor -etc.
Last year, I switched to eating paleo.
For the first couple months, it was kind of tough while you body becomes a fat burning machine instead of a sugar burning machine.
for what its worth, i ran everything from 5k to 15 mile races last year with no problems.
My advice to you is stick with what you are doign right now, if it doesnt work out, add some safe starches.
ps make sure you are eating enough fat.
i'm like you- started running a few years ago and it's something i love. i don't run long distances (5mi at the most), i'm mostly a sprinter. i don't go by the glycemic index, so i don't know how invested you are in sticking with that. one of the things i love about the paleo lifestyle is the spectrum of options based on what works best for you. if you need fruit, eat it! i eat moderate amounts of fruit (maybe 1-2 servings a day) and i also drink a cup of coffee in the morning. i don't think there's anything wrong with tweaking your diet so that you have energy for what you love doing.
I was glad to find your question. I just started eating a very low carb diet, and my last two attempts to run have been horrible. I had been averaging 25 to 30 miles per week, but my attempts at a 12 mile run on Saturday and a 6 mile run today were epic failures. I wasn't sure whether it was all in my mind, so it's comforting to find that others have experienced this as well.
I have been on the Paleo diet for a month and have notice a Hugh difference. I have more energy and more endurance through out the day. I have lost 15lbs.
I use to run cross country 20 years ago, living on SAD Standard American diet, and my top run was 16 minutes in 3.1 miles.
Now since I started on the Paleo diet, I have started running again. Normally after my run, 6AM in the morning, I make a 32oz carrot, apple, and celery juice. Sometimes I may add cucumber, a green, or a lemon. I have found that this really gets my day started with a lot of energy. I snack between meals, maybe a grapefruit or something healthy. During the evening I walk 1 to 3 miles with my one year old baby girl, she adds an extra 20lbs when I carry her. During late evening after my meal, I will take a pro-biotic and my vitamins also, I may juice that evening, ex. apples and a whole lemon with maybe 1 or 2 carrots. I try to juice 3 hrs before bed if possible or I might have to get up during the night. By 5AM in the morning I am very exuberant. I try and document everything and keep my doctor informed of my progress.
In 6 weeks I will be running a 5K since 20 years ago. Life is awesome going Paleo! But the most challenging thing, besides the change itself, is finding new recipes that I like.
Also, I was 135 lbs and a teenager when I ran 5mins and 20 seconds per mile. One month ago I weighed 192 lbs and now down to 177 lbs. My time now is around 9minsand 30 seconds per mile. So it is not easy as it may sound. But the Paleo change is the right way to go and I know it has help my running.