Dairy
Your holier-than-thou vegan friend may be on to something. 65% of people are lactose intolerant, making your late night Artichoke slice a risk right before a beach weekend. While the thought of a beach day without a classic soft-serve cone with sprinkles is depressing, dairy can cause uncomfortable bloating, abdominal pain and diarrhea. Yikes. Maybe hold off on that Black Tap Milkshake until after your beach trip.
[Photo via @elizabethkeene]