First let me ask the walnut question. I bought walnuts for protein and because I read they're a good snack. I look at the nutrition facts and for one serving (I believe half a cup), it's 200 calories, 19 grams of fat (1.5 g saturated). I wanted nuts with the intention of padding my protein stats, but instead it looks like they would pad my fat intake. Should I steer clear from these?

Now for the feel weak question, I'm 200 lbs, 5'10 and want to lose weight. I've been dieting now/doing cardo for 7 days, and besides one cheat meal, I've pretty much stuck to 2000 calories give or take (some days a bit over, some a bit under). I feel weak though.

I think it's either because A.) perhaps 2000 calories is too little, or B.) since I just started, now I'm in the transition phase from 'junk mode', so my body isn't used to eating these healthier foods and less calories in general. If B is the case, I assume the body will adapt after I'm on the diet more.

Thank you!

http://www.nutritiondata.com/facts-001-02s02f5.html

http://www.nutritiondata.com/analysis-help.html#protein%20quality

Walnuts are a lousy source of protein. Not only do they have a small amount of protein relative to fat, as you pointed out, but they don't even provide a complete protein. Check out the "protein quality" graph at the bottom of the page I linked and it'll show you what I'm talking about. Any score <100 is an incomplete protein; Walnuts score 51 :p

As for the weakness issue, it sounds normal. I felt pretty lousy when I first started eating properly. I'm assuming of course that 2000 calories is not just some arbitrary target you picked. If your research indicated 2k calories is what you needed, then stick with it a while longer. If you continue to feel weak, then you might want to consider increasing your calories gradually until you feel more comfortable. There's no sense in starving yourself and then falling off the wagon.