I was essentially doing this diet tho it was based off of knowledge that I cultivated compared to a system that I learned about. Make sure that most of those 50 carbs are fiber otherwise you will be ****ting out your protein. Also most carb heavy items besides grain contain most of your nutrients meaning vitamins and minerals. You need to take much in the way of supplemental vitamins and minerals. i use ultra start vitamins from freshstartvitamins.com I was doing this for about a year and my weight dropped off and little exercise on my part so I can imagine someone with an active lifestyle. Good luck. Remember processed foods suck. You are a processing machine. I took around 250 g of protein and 75 g fat. Usually good omega fats from flax seed and tuna/salmon. Need to learn to love the fish with this diet. if you have a George Foreman that is helpful as well. It will drain most of the fat from your meats. If your a herbalist as I am it will help to contain your metabolism so your not a s hungry all the time. At first cutting those carbs made me loose energy but after the first month and with help with the vitamins I had double the energy.

My son's neurologist put him on the ketosis diet for his seizures, not to lose weight. He hated it, his breath stank all the time, he had little energy, and he did not see any improvement in seizures. I followed it for a week and hated it also because I was training for a half-marathon, running 25+ miles per week, and doing MA training. It sucked. Maybe you'll like it. Who knows. I've had a lot more success just cutting out refined carbs.

I've recently heard about the ketosis diet (a friend of a friend's apparently lost 30 lbs on it in 4 months).

The basic idea is that you cut out almost all carbs (50gram daily allowance maximum) and focus on protein and good fats. This is supposed to put your body into a state of ketosis, where your body stops burning carbs for energy (because there is none) and starts burning fat while not reducing muscle at all.

I am doing Kung Fu classes twice a week (beginner level fitness) and exercising 2 or 3 times a week besides that (mostly cardio, form repitition and body weight resistance training). I have been struggling with my fitness as i am carrying too much fat and my cardivascular fitness is really bad.

Has anybody been on this diet while training? Do you think it is something worth trying out or something that is likely to be bad for your body?

If you're interested in alternative diets, you might want to look into the Primal/Paleo stuff. It helps by reducing carbs (compared to what's known as the Standard American Diet), but provides more leniency around adjusting your carb intake to meet your actual needs, as well as providing a more sustainable framework around choosing which carbs to consume and whatnot, so that you can maintain it over the long term (and, therefore, not have to "go off of it" and end up gaining everything back; remember, if you don't want to yo-yo, your diet should be something you can commit to - a way of eating - not something you hop on and off).

The simple truth is that endurance training (such as cardio, particularly high-intensity, for an hour or more) requires glucose (carbs) to fuel the body during the workouts. As such, the extreme ketosis diets (<50g of carbs) are generally not sustainable for such athletes for more than a week or so. However, you can still get a lot of the same benefits by cutting down on your carbs, while still consuming enough to fuel those longer workouts. Even most of the most hard-core keto athletes will tell you it's hard as hell to sustain and they're only actually in it for a few weeks at a time (non-athletes can often do it easier, since they don't need as much energy in general), and even Atkins only does the extreme keto for the first two weeks (afterwards, you start slowing increasing your carb intake until you find what suits your needs).

It's also entirely possible (not to mention surprisingly easy) to get the nutrients you need while consuming 50g-150g of carbs a day. The key is knowing what sources of carbs actually provide you benefits other than the carbs themselves. Green leafy vegetables (kale, spinach, good lettuces, etc), carrots, tomatoes, broccoli, peppers, sweet potatoes (for the high-carb days) and other types of squash, berries, apples, and so on, can give you all the carbs (and fiber) you need, and are packed with tons and tons and tons of nutrients. Grab high-quality meats (grass-fed, pastured, or wild-caught, if at all possible; and avoid the factory-farmed crap) to get things like iron, omega-3 fatty acids, good fats, and of course protein, to top it all off, and you have a nutrient-dense, filling, and satisfying set of meals.

If you're interested in something like the above, I recommend checking out http://whole9life.com/2012/08/the-whole30-program/ and http://www.marksdailyapple.com . Nerd Fitness also has a great "beginner's" article, which gives an awesome overview of the Paleo Diet (as well as his thoughts on its criticisms) http://www.nerdfitness.com/blog/2010/10/04/the-beginners-guide-to-the-paleo-diet/ .