[Most Likely]

Forcing a vomit isn't really a good idea, never... Even when you eat junk food. Your body doesn't right away notice what you eat is normal or junk food, so when it feels your stomach is filled, it reacts in the same way, making you feel like throwing up. Especially if you excercise, DON'T MAKE YOURSELF THROW UP. If you excercise you need calories to a bit bigger degree. Instead of thriowing up junk food, it would be healthier not to eat it at all, cause it definitely doesn't have much health benefits.