What's the difference between American and non-American manufactured Mars bars?

International Mars bars have three main ingredients while American bars add a fourth: almonds. Aside from that, the composition is identical.

Can someone with a nut allergy eat Mars bars?

Even the non-American Mars bars contain nougat, which is often made with at least one type of nut and can still cause an allergic reaction.

How many calories do Mars bars have?

A fun-size Mars bar has 80 calories compared to 210 calories for fun-size Hershey bars, 190 for 3 Musketeers bars and 180 for Nestle's Crunch. They also contain 2 grams of protein.