Newbie lifelong fast food eater - changing my ways!

Hiya, I'm no good at these introductions, but I figured I should say something here in case I need help down the line. I will confess that I've spent the last 30 years or so eating out, and eating fast food for at least one meal a day, usually throughout the week. That's a lot of crap in my system, and it's really, really not happy with me.

I started reading food labels about 3 years ago, and I'm trying to cut out HFCS and reduce soy and salt intake. I switched to wheat bread about five years ago, real butter (though I use it sparingly) about 4 years ago, seriously cut down on pasta and sauces, and frozen foods loaded with sodium.

I'm about 20lb overweight, or at least that's what I and my doctor would like me to lose. This year especially, I've really started to change my eating patterns. For March and April, I deliberately did not eat ANY fast food, instead either ate at restaurants with the family (maybe 4 times) or cooked at home. I didn't see any weight shift, but I wasn't measuring anything so I don't know how many calories I was consuming. I fell off the no-fast-food wagon in June as I had to help with a wedding, but my doctor just had me on a 3 day fruit/veg drink detox (yuck) that left me with a 3-day headache, leftover food and not much else. I did a detox in 2011 that saw me lose 20 pounds, and I've kept that off. I've been at my current weight of 163 since, and I'm tired of it.

I've started yoga and cardio and walking and other light exercises, but I can't stay motivated to keep at them.

On a personal note, I'm a huge sci-fi geek with a 17 year old cat named Methos. He's got a thyroid problem but he's doing fantastic. I'm in the Midwest, so we have muggy, humid, disgusting days that make walking tough until the sun goes down. I don't really have a history of heart disease or medical issues in the family, so I'm hoping by changing for the good, now, that I'll live long and prosper.

Thanks,
Jenny