Eating advice before, during, after weight training?

Hi, everyone. 

Background:  I am a year out from RNY surgery.  Due to a chronic Achilles injury, I have not done a lot of exercise--most forms of cardio are quite painful.  However, in past years, I did a lot of strength training, and with the new year I decided to return to that.  I have started working with a trainer who specializes in kettlebell work.  So far, I am happy to feel that I am becoming stronger again.  I am also really happy with the cardio options that I can do with the kettlebell, which do not seem to aggravate my Achilles.  (Hooray!)

Question:  During the workouts, I have been getting lightheaded.  There is a lot of up and down, of course.  I have felt this light-headedness might be due to needing more hydration.  But the trainer has also suggested having carbs before, during, and after the workout.  I hesitate to add in any carbs.  I still need to lost 20 more lbs to reach goal.  But I could space the carbs I do eat (yogurt, etc) around the workout.

I assume there are some very knowledgeable people here--in your opinions, what is the best nutrition approach for a post-RNY person to have the needed energy for a weight training session?  I am not trying to bulk up--just trying to have the energy I need for the sessions.

Thanks for any thoughts!

I only drink before and during exercise.  Then I protein it up after working out.  I lift three times a week, so that works for lifting as well.  

If you find more hydration doesn't help, consider adding something protein-y before you start, but something that'd be easy on the stomach.  Like a shake or yogurt.  

Thanks, Gwen.  I am happy to hear from your experience.  I have read a lot of your posts and really value your insights.

In my non-expert opinion, you don't need more carbs.  You might be lacking in electrolytes and sodium.  You have to do some serious working out for some serious time before you work through your carb stores and enter bonk territory.  So I would say look to increasing sodium and electrolyte levels pre-workout (and during) to see if that helps.

Thanks.  That makes sense.  I have a son and husband who are really serious athletes, and I see their nutrition during races and training--I definitely do not need that kind of thing.  Even years ago when I was much more fit, and I would train hard (would run for 2 hours or lift moderately for an hour), usually just getting enough water was good for me during the workout, and then something small afterward.  So I appreciate your advice and reminder!

Have you had your iron checked?