A: Yop, I'm blond too and cannot control myself when it comes to food LOL. i LoooOOOoooove food. (slurp yum crunch slurpslurp).
As I said before, bettas are aquatic pigs. They'll eat just about anything you toss in their tanks (veggies, shoes, small infants LOL). This can be great if you want to get rid of a dead body. Heck, I am surprised Tony of the Sopranos has not figured this out yet. All he has to do is get a couple of bettas (forget about the messy meat grinders etc...!) LOL.
OK, enough nonsense, let's tackle your question.
When bettas eat, their stomach expend. You'd be surprised just how much they can expend. I illustrated this with my virtual betta in the "feed live worms" clip, where the betta gobbles up so many worms it becomes HUGE! I know this is a cartoon, but some bettas really do turn into balloons after a meal. Heck, they can eat SO much that they no longer can swim and lay at the bottom, on top of their huge round bellies, head down and tail up, looking positively pathetic (and quite hilarious). I usually try not to laugh - or at least I don't let them see me- because bettas in that state are very vulnerable and their feelings get hurt real quick. Then they build resentments and the next time you stick your arm in the tank to clean, you come out with a stub (yikes)!
Since bettas do not have any self control when it comes to food, you must be the voice of reason and regulate their calorie intake! Training your eye is important, so that you can quickly assess how much to initially give them and whether your bettas need a second helping or not. To help you, I have added photos to my betta food page. These four photos will show you what the perfect belly should look like, and 3 other bellies that are not so perfect LOL. The fourth photo shows a female that has turned into a balloon. And I promise you that if I had fed her some more she could have been even larger. Although it is necessary to feed growing fry a LOT, and they usually DO look like balloons after a meal, this is not acceptable for a grown mature betta.
So check out that page and the new photos and learn!
Meanwhile, all this talk about food has made me angry, so if you'll excuse me, I got to go stuff my face ;P .