Whenever he thought about it, he felt terrible. And so, at last, he came to a fateful decision. He decided not to think about it. ~John-Roger and Peter McWilliams
Q:

Dear 100 Hour Board,

Could a lion get enough nutrition from bugs to thrive and grow into a healthy young adult, as depicted in The Lion King? How many bugs would he have to eat per day?

-Rainbow connection

A:

Dear Kermit, 

1) Could a lion get enough nutrition from bugs to thrive into adulthood?

No. Definitely not. According to a lion expert, you can't be a large carnivore and survive on just grubs. It just wouldn't go well. One 1999 study (source found herestudied carnivores to figure out how big they could get if they only ate bugs and found "a maximum sustainable mass of 21.5 kg" That isn't very healthy, considering the average adult male lion is about 217.7 kg... So while you may need to eat your veggies to grow big and strong, it turns out wild cats need real meat. 

2) How many bugs would he have to eat?

This nifty Reddit thread has it figured out if you want to go more in depth. Basically, an adult lion needs to eat about 25 pounds of food in a day... and that thread explores some different kinds of grubs for Simba to eat, but the essence is that he would have to eat between 3780 and 9450 grubs a day, or about 24,292 crickets. He would literally have to be consuming several bugs every second, if he wanted to spend any time sleeping. 

Of course, Disney isn't famous for the biological or historical accuracy of its movies. *Shrug*

Cheers, 

Guesthouse

P.S. Brownie points and credit goes to Goldie Rose for doing the research for this question. She was busy packing and moving this week, but I appreciate her efforts.