Children's hula hoops are too light for adults and won't stay up. You can get a weighted hula hoop, but don't go over 3 lbs., especially if you're a beginner. An adult dance hula hoop (one and a half pound weight) will allow you to boogie and perform tricks like whirling it over your head and back onto your waist.
A small adult hoop measures 38" in diameter and weighs 1.525 lbs and a regular adult hoop measures 42" and 2.0 lbs. There are many videos on the market for beginners to learn a weighted hula hoop workout.
Ideally the weight of the hoop is sufficient to allow you to maintain the hooping rotation and preferably work up a sweat--then the hoop is the right size and weight even if it only weighs one pound. Collapsible hula hoops are great for taking on vacation. It helps to keep you on track and still enjoy those all-you-can-eat buffets on vacation.
"Through our years of experience we believe 38" hoop at approx. 1.5 lbs and the 42" hoop at approx. 2.0 lbs is the ideal size and weight to trim inches off your waist and for overall fitness."
Heavier (2.0 lbs) and larger hula hoops for adults rotate slower and are easier for the beginner. You can buy hula hoops online, custom hula hoops or make your own. To pick the right size, stand the hoop in front of you. The top should be between the stomach and the middle of your chest.