Jillian Michaels 30 Day Shred, Are The Weights Necessary?

My two problem areas are my waistline and thighs. I am 5 foot 3 inches and weigh 140lbs. My waistline, at the widest, measures 34 inches and each thigh (also measured at widest) is 21.5 inches. I was wondering if I would still get pretty significant results if I didn't use any weights at all. At the moment, I do her Yoga Meltdown dvd along with jogging but like with any workout, my body has adjusted and I have stopped seeing results. I am thinking of giving the 30 day shred a try but I really don't want to use weights. So are they really necessary? If it's any help, my goal is to get my waist down to 30 inches and each thigh down from 21.5 inches to 18 inches.