So I recently started up atkins diet back on dec 1st to be exact. I have done lc for many years on and off. This time I plan to make it a life change not just a diet. But anyways I have been doing 40-60 minutes cardio a day 4x a week and then about 15 minutes of curves circut training machines only freestyle. I was wondering how much cardio do I need vs. strength training to see optimal results. My diet is very high in protein and very low in carbs.
Im pretty active and would just like an extra umph to my workout plan to make weight loss more effective. Any advice would be great...so tell me what works for you..
Ps. I plan on training for Down Hill mountian biking like serious kind. My brother is very good at it and he said if I got in shape he would teach me. So theres my ultimate goal.

Well I am not as active as you but when I CAN be, I would flip your cardio and strength training and do more strength and way less cardio.

I like the exercise idea at Mark's Daily Apple, have you seen that one? He used to be a cardio king but when he changed that to :

1) easy fun moving every day
2) strength training 2-3 times a week
3) all out intensity or sprints 1-2 times a week

He got better muscles and better performance with fewer injuries too. \

http://www.marksdailyapple.com/body...s-and-body-fat/

I can tell you of two examples that I have personally gone through.
1) 9 years ago- I was 285lbs. I adopted a high protein, low fat, low sugar, low carb diet and did weight resistance training 4 days a week (I did the push pull method) I did not work my legs at all. But my job at the time was a Tower Climber- so essentially I was doing a stair climber type movement everyday.
other than that I did 0 , nada, zilch cardio. One day I jumped on my treadmill and I ran 4 miles at a 7 minute mile pace. So that is 4 miles in 28 minutes. I got bored running on the treadmill after 30 minutes and just stopped it. I felt super fresh and could have gone further but just was bored.
2)this time around (2007) I was a little over 300lbs- I again adopted weight training and low carb, high protein diet and lost 85lbs in 12 weeks- I incorporated distance running into my program and did not do any resistance training at all- I ate more carbs (because that is what runners do) and my best time for a 5K was 24 minutes (4 minutes slower than when I wasn't even running in example 1)
Now you could say- well you are 9 years older- you were not the same weight, etc.
But I do think to be able to run 4 miles in 28 minutes says alot for what weight resistance training can actually do for your cardio.
Well that is my $0.02 worth.

If you're losing the extra weight steadily, I would wait and give it more time. You might be losing enough already.

Otherwise, maybe dropping some calories, depending on where you're at now. You seem to be doing enough cardio, so I would only increase the circuit training at this point. Try 20-30 minutes and see what happens.