what affects does it have?

Crash diets are meant for quick weight loss and don’t differ all that much from pure starvation. So what you’re doing is you’re depriving your body of the nutrients it needs, torture it for a few days, lose some weight (maybe) and then when the diet is over - guess what - you gain it right back! At the end of the diet you’re so deprived that you’ll feel even hungrier than normal cuz your body wants to catch up. So in the end crash diets are not only agonizing during, but very disappointing after, as the results don’t last. Well-paced and well-balanced diets are what keep weight off once you lose it.

About the esophagus - yes it can be damaged; a side effect of bulimia is “burning” of the esophagus and “rotting” of the teeth, because the stomach acid which you’re throwing up with the food is very strong and basically eats away at whatever body part it passes by. The stomach itself has a protective lining which sheds all the time so it doesn’t digest itself, but the thing is, other body passages are not protected, so the acid just wants to digest them as well. That’s why it’s important to drink some water after you throw up to wash the acid down, and brush your teeth right after. But of course, the best thing is just to avoid bulimia altogether!