How much millet should parakeets eat daily?

My budgie will eat an entire twig of millet in a day if I leave it in the cage, and ignore his pellets -- so I've taken it out of his cage and only give it to him under supervision and when we are training as a treat. They should never eat more than one full twig a week, they're a healthy snack but they are high in fat and he will become overweight if given too much. Good luck!