if it isn't your natural body type, not much. you can keep your overall weight down, and do exercise. I have thick thighs and since I work out the gym with both weights and cardio, my legs are toned and solid and somewhat thinner than they were. but they will always be thick, even though I'm not heavy. at my thinnest weight they were still pretty thick, and I'm not fat now, but when I was at my thinnest I would starve myself so yeah.