Safe to water fast if 100+ lbs overweight?

hi, i am considering doing a longer water fast(30-40 days). I am 20 years old, male, 6'2" and weigh 326 lbs. I would like to get down to around 220 as my first goal and see where we are when i get there. I don't have any medical problems that i know of. Is it safe for me to go for around 30 days on just water.

Oh, and i have done a 6 day Water Fast in the past. Thanks. Tweet