Did not hear the interview with Matt Lalonde on superhuman radio yet, but his experience is described in these two web pages as well:

First, a post in which he sings the praises of crossfitting while low carb: http://robbwolf.com/2009/10/08/crossfit-on-a-low-carb-paleo-diet-mat-lalonde-reporting/

Later he appeared on the Paleo Solution Podcast and said that shortly after he wrote that piece (3 to 4 months of LC + CF) he crashed. It resulted in his testosterone becoming "pretty low" and his cortisol "really high." He now advises "If you are going to do high-intensity exercise, you should eat the carbohydrate that goes along with it." Here is the transcript of the interview (see question 3): http://robbwolf.com/wp/wp-content/uploads/2011/02/the-paleo-solution-episode-68.pdf

You're going to run yourself into the ground with <30g carbs+competitive CF in the long run. Expect hairloss, loss of libido, performance plummeting, hormonal imbalances down the line. Just not worth it.

Its the worst diet possible for athletes. Eventually once the adrenalin wears off and your glycogen is depleted you will lose all your power, drive and general ability to function(along with a hefty dose of lean mass).

Doing crossfit on a ZC diet is like banging your head with a hammer, nothing good can come of it.

I would like to know a little bit more on this from other people's experience. I went low carb, then almost completely carnivore, and experienced fatigue that was abated when I started eating white rice. However, rice and potatoes seem to really increase my appetite and cravings for sugar. December was very-very-very un-paleo and I'm trying to recover from it now, but with a much bigger appetite than I've ever had. I'm thinking about going back to VLC but I cycle 25km a day, go to a barefoot running club once a week and also would like to start doing weights. Has anyone had experience with that kind of activity with just green vegetables or things like carrot, etc, as carbs?

Im a paleo body builder, I have bananas and whey in a shake pre workout, and sweet potatos post workout with my meat. That is all you need.

Carl Lanore just did a great interview with Matthieu Lalonde, he also talked about his experience on VLC + Crossfit

http://www.superhumanradio.com/

-> SHR # 884 - Transdermal Fat Loss And Hydroxycobalamin Patch Introduced PLUS Matthieu Lalonde's Paleo

btw, lots of other great info from Matt

http://kellysayswhat.blogspot.com/2011/07/hitting-wall-part-3.html

I suggest you review research done by Stephen phinney.

This blog post is a short summary. In general, endurance falls for the first 6 weeks then Returns to normal once one becomes ketoadapted.

You can eat this way, and get the necessary vitamins, but only if you are eating the right foods instead. It's hard work reconstructing a nutritionally complete diet.

Training will become difficult to maintain at high intensity, but feed up on carbs the day before a competition and just see how fast you go.

1) Once liver and muscle glycogen are thoroughly depleted, you won't be able to avoid experiencing rapid fatigue during anaerobic activities. Fat cannot be burned anaerobically, so any ATP will need to be generated either from the little glycogen you have or creatine phosphate stores (which will be depleted within seconds). Also, the presence of lactic acid directly inhibits fatty acid oxidation. Increased fat consumption does, however, increase IMT stores which are glycogen sparing at reasonable (say <80% VO2max) intensities, and that glycogen sparing effect may be the stimulus behind the initial "oh this is so great" phenomenon (my speculation). But ketogenic diets can't be sustained if you want optimal anaerobic performance.

2) Maybe, maybe not. If you eat offal and all parts of an animal then you may be generally okay, but is it optimal for long-term health to eat no/very few vegetables? Likely not.

3) This is really tough to succinctly answer (you might argue this whole website is devoted to this and similar questions), so I'm just gonna pass :)

I haven't heard a whole lot of evidence that VLC diets yield great strength gains; however, the positive changes in anabolic hormones with increased fat consumption (by replacing carbs in a higher carb diet) are well-documented.

All of that said, feel free to give it a try. I did, but found that after several weeks my anaerobic performance decreased substantially. Adding a PWO banana shake and a sweet potato or two a day brought everything right back to normal. VLC diets sound cool on the surface, but in reality you can't ignore the higher oxygen efficiency when processing carbs vs. fats nor the fact that fat can't be burned anaerobically.

Hey man, this is an excellent question for everyone!

1) I had incredible strength benefits from going really really low carb at first, then once my glycogen stores became really really low (even Neoglucogenesis can't keep up with a super active lifestyle) it began to take its toll. I was doing basic high intensity exercises like pushups, pullups, burpees, etc.. and I was also running 1-4 miles a day depending on how I felt. And like i said, at first it was incredible, I hated running but was soon blasting through trails at quite a decent pace without being exhausted... this lasted for about a month. Then came a point where I physically couldn't run more than a half mile without walking. I hit a wall, it also affected my training... I was breathing heavier and couldn't increase my intensity during calisthenics. I didn't realize it at the time, but it was due to my ketogenic lifestyle (<50 g carbs). This also happened with a girl I train for the childhood obesity program that I run, who does cross country. She felt herself becoming exhausted, and she's an excellent runner who once starting paleo cut over 3 minutes off her 2 mile time. When she told me of her issue I immediately remembered my own, and I told her to eat some fruit post workout. (it obviously will only be stored as glycogen and not fat) So she did, and she is still continuously losing weight (over 40lbs down) and is hitting new PR's ever single time she runs. So I don't know if the same will happen to you, but this is just my 2 cents from my own experiences. (and most people will tell you active people need SOME carbs.)

2) It is possible only with supplementation. Your best bet is to eat Fruit post workout, but obviously don't over do it! :)

3)As to this 3rd question, you can pretty much grasp an idea from my 1st answer.

GOOD LUCK! and I hope this helps you!