I heard phoenix worms are really packed with calcium, the problem is they are very fatty, they are very good in moderation, due to that they are packed with calcium.
Phoenix worms are relatively LOW in fat:
Click to enlarge:

(quoted from the Phoenix worm website)
Genuine Phoenix worms have a naturally balanced calcium : phosphorus ratio.
"
Phoenix Worms are the only calcium-rich feeder with the perfect balance of calcium and phosphorus, 1.5:1. ............ Breeders report that hatchlings that are fed PWs right from the start are more than 30% larger than their clutch mates after just a few weeks! They also note higher activity levels and brighter colors for the babies that were fed PWs.
Here's why you will like this new premium feeder insect:
Phoenix Worms are ready to serve when you take them home. There's no need to dust or gut load these insects before feeding your pet.
Phoenix Worms are low in fat and naturally have 23 to 61 times more calcium than other commonly fed feeder insects!
---No need to culture them
---You don't feed them
---Stay fresh in their cup for weeks at room temperature (even longer at 50-60 degrees)
---No noise
---No odor
---Will stay in a dish--no escapees in the house!
---Convenient to take on vacation--or easy for a pet sitter to serve while you're away
You're going to enjoy watching your pet discover this new food. People tell us that their animals get excited when they see the "black cup" coming!
Here's why your pet will love Phoenix Worms:
---They wiggle like crazy which excites and entices herps. Great food for a picky eater!
---They taste good (a guess, but herps greedily consume them)
---Come in four sizes to satisfy most pets, from darts to dragons
(largest is 3/4 inch only)
---Stimulate the appetite of animals that don't readily feed
---Can halt or reverse the effects of metabolic bone disease
---Provide a boost of nutrition for gravid or just-laid females
A great start for all hatchlings!"