I need help losing weight before my vacation in 3 weeks!?

I am about 20lbs overweight- I have been yo-yo dieting with the low carb atkins diet for about 10 years and I am getting tired of losing and gaining- but i need a quick fix for vaca- should i suck it up and do the low carb to lose the extra lbs quickly? or should i do the 48 hollywood juice diet to jumpstart my weight loss and then go right into weight watchers?? Thanks!