Hey Joe-
I know exactly what you are talking about, and the reason is because I had the same problem. I used to be overweight and I had asthma, and then I had an eating problem and went down to nearly 99 pounds at 5'7". It was gross and even then, I was not tightened in the abdominal area nor did I have anough stamina to last running, I could only do a mile in 8 minutes and could not continue running afterwards. That was a few years back. I have yoyo'ed up and down since then, and about a year ago to the date actually (it was april 28 of last year, my mom's birthday), i decided that enough was enough. I felt like crap, had no energy, could hardly focus...even my hormones and emotions were going haywire. I do totally related everything back to my diet and physical condition. I was not overweight at the time- I was 5'7", 138 pounds, but i certainly didn't feel like I was in shape. I bought fitness magazines, I got fitTV through directv (which is the best channel ever, by the way) and I began a regular exercise program. I did an hour of aerobics 3 times a week and Abs of Steel on the days I didn't do cardio (but just the ab exercises. not the aerobic segment). I started to look and feel better, and my endurance and stamina built up. Once I could do that with no problem, I would add weights to my ankles while I did the aerobics. Around September I started doing TaeBo (the hour advanced workouts, "Get Ripped"). So at that point I was doing 2 hours of taebo every other day, and on the off days I switched to weight training (45 minutes). I would do legs & glutes, or chest & back, or core - Check out Cathe Friedrich workouts. With all this work I was doing, I still had loose "skin," fat..whatever....a combination of the two, on my belly. I have always had it since I was seriously overweight (5'4, 150). Anyways...I noticed my body changing, especially my legs, hip flexors, arms, calves, thighs....my thighs (especially inner thighs) took soooo long to define, as I thought there was extra skin there. But I know now that in order to obtain completely tight skin, it is a matter of diet. Whenever you choose to eat a meal (and I do not endorse liquid diets, as they do nothing for your metabolism and had a tendency to give you cramps), think to yourself : "If I lived in a natural environment, would this food be available to me?" That means no dunkin' donuts, mcdonalds, processed sugars...nothing containing high fructose corn syrup, or hydrogenated vegetable oils...even if whatever you are consuming may be low fat, the unnatural sweetening and processed ingredients will hurt you in the long run, providing no fuel for the muscles or metabolism.
Anyways... My thighs and abs were the absolute last thing to go on my body. I found that Cathe Friedrich's Legs & Glutes is the best workout for my lower half, as well as taebo, and for my abs I trust taebo & Cathe's Core Max Workout. I trust her because she has been a fitness instructor for about 20 years now, and is incredible shape. She does not endorse any surgeries or fad diets, and most importantly- look at her pictures of her during pregnancy. Then, compare it to her pics 6 months after she had the baby. No stretch marks. No extra skin. A healthy person taking in nutritious foods will be able to spring their body back to life. I am walking proof, and so is she. I will try to get pics up of my abdominal area after class today.
For quickest results, try the small 6 meals a day and check out Cathe's "Boot Camp." Incorporating weights into the workouts will burn twice as much *FAT* as opposed to muscle or water weight.