Shouldn't happen. But if you are breeding adults you will notice just how much it takes out of both boys & girls... and at that point your replacing lost body weight with a bit of minor growth. Girls can lose over 1/2 their weight laying eggs, males lose weight courting & breeding... males who are pulled from breeding still take their sweet time going back on feed, even though their weight fluctuates less than the girls.
Now, snakes that aren't being bred? Well, I've a few that are on break any given season- I do not breed an adult snake every year here. Again feeding for this is different. As long as you keep good records I still believe it's simple to do right by your animals.