low carb... will it hurt my ability to train?

If you are on 50g of carbs a day that is 200 calories, so somewhere between 10 and 13% of calories from Carbs. Way too low in my opinion.

As a person that has to go low carb (diabetic) I know I am missing out on other essential nutrients.I am sure you are as well.

Rather than go so low carb you may want to go low GI and a little more carbs.

Below 30% of intake is pretty low. I am guessing you are doing this for weight loss. Low GI will have the same/similar effect and allow you to get the nutrients you need.

It CAN work for you, but that doesn't mean it's going to.

If you scroll down this page of threads you'll see a post by a guy here with the username "batlou" who does Atkins and endurance sports and has had a good experience with it.

http://www.beginnertriathlete.com/discussion/forums/thread-view.asp?tid=416326&posts=79&mid=3939370&highlight=obese&highlightmode=1&action=search#M3939370

I suggest you check out Paleo Diet for Athletes. They discuss timing of carbs for recovery and energy.

Basically have the carbs around your workouts.

Also, you may want to increase your healthy fats to help with the lethargic feeling.

This is very true. Timing of carbs is critical. After a workout your body is very insulin sensitive and the best time to take on carbs, get the other nutrients associated with higher carb foods yet prevent the insulin spikes.

There are also times of day we are more insulin sensitive.

I am low carb and also find that the Paleo Diet for Athletes is well written and helps. By the way, I had no idea what Ketosis is.  That doesn't sound really good, especially for an athlete, but I'm not a doctor either. 

From my experience, 50 grams is far too little if you are an endurance athlete.  I don't count my grams daily, but I'd guess I'm more around 100-150 grams a day.  Sometimes a lot more before a race or hard workout and sometimes less. 

The trick, especialy if you have gut issues, is how to do this without lots of bread and pasta. Yams/sweet potatoes, squash, wild and white rice, fruit.  I still eat some grains, too, while training. A bit of pasta or good bread isn't going to kill you (usually). 

As mentioned above, the timing really helps. 

^^^ is the way to go. If you do strict Atkins and keep your carbs under 50 your workouts will suffer especially if you are training for Olympics or longer races.

I have done Paleo for Athletes in winter.

Another vote for Paleo for Athletes as a great resource about timing.  I've been paleo since last August and while I'm not super low carb (~ 30% of my cals), I would venture a guess that my workouts are better than they used to be because my recovery between them has significantly improved on this diet.

I do time my carbs though, so I'll eat sweet potatoes or fruit smoothies around tough workouts.  Oh, and for longer workouts (longer than an hour), I supplement with non-paleo carbs in the form of gels.

By the way, carbs don't have to come from grains at all.  I eat zero grains and get my carbs from potatoes (sweet mostly, but some white on workout days) and fruit.

I've been doing the Paleo thing since 12/26. I've actually been keeping the carbs to near zero this week out of fear of overdoing it. I felt it yesterday after a hard week of training. Could not string a thought or sentence together by evening and it took a Coffee and a Gatorade pre-drink to get me through swim team.

I learned my lesson and will go back to making sure I have some carbs a few hours before a workout, and shortly after to re-load. I did that the week before and moved smoothly into the last hard workout and week.

If you are wanting to lose weight and maintain energy cut out these foods first in this order:

1/ All dairy (liquid Meat) Take a calcium tablet.

2/ All Soda - Non Negotiable here this stuff is toxic. when I gave up soda I dropped 5lbs and my GI Issues dissapeared. Replace with Seltzer.

3/ All Sugar - Including Cookies, Sugar in coffee etc replace with one cup of low fat Frozen yogurt per night as a treat.

4/ Replace Refined grains with whole grains.

5/ No Coffee after 1pm.

I do 1/ and 2/ & 5/ struggle with 3/ and for the most part are pretty good with 4/ I dont; worry about carbs for the most part but do try to eat more after a work out. I don't have any nutrition while training less than an hour and a half. I always follow the 80/20 rule and try and eat well 80% of he time.

Good luck

in order to lose weight you need to create a caloric deficit...

That is the only thing u need to worry about.

During the off-season I go more towards low-carb to keep the weight down, but the minute I start training hard, I add good whole grains back in.

As a specific example, on rest weeks and off-season I'll eat eggs with veggies for breakfast. During training weeks, it's steel-cut oats, a piece of fruit, and a little all-natural nut butter.

So I alter the balance based on my activity level. It's what works for me.  High carbs during low activity make me feel bloated and gross, low carbs during high activity don't give me enough fuel.

If your goal was only to loose weight I would agree 100% with this!  And for people that are overweight to obese I would agree that that should be their primary goal.  But someone who is an athlete trying to go from a reasonable weight down to a super lean race weight?  It suddenly gets far more complicated because that person is concerned about a lot more than just weight loss.  What they want is FAT loss while maintaining muscle mass and sport fitness.  Now you need to worry about keeping in a caloric deficit while training hard enough to convince your body to hang on to muscle and providing it enough protein to repair and maintain your muscle mass, because if it thinks it might not need that muscle or there isn't enough protein available it will get rid of it in a hurry.  You also need to worry about your carb intake, timing, and the GI value of those carbs.  Gets far more complicated when you bring fitness and performance into the equation.  And the more elite you are the more complicated it gets.

As for the list of things to cut out.  I would put sugar at the top of that list, not #3, unless were talking about gu during training or something.  Why dairy?  I consume a huge amount of dairy.  Plenty of complete protein, calcium, vitamin D, fat, only sugar is lactose which isn't bad for you, no sucrose or fructose or anything.  I usually drink a pint or two of milk after most workouts. 

thank u!

u see, that is the problem!

u are trying to accomplish two thing that are very different by nature at the same time.

IMHO why make so complicated?

Create a caloric deficit by training and/or dieting; lose as much weight as u want and THEN worry about performance and fitness.