Learn Russian: Из-за сахара этот торт содержит более шестисот калорий. - Because of the sugar, this cake contains more than six hundred calories.

The word более (more than) requires the Genitive case. To put a hundred-number like шестьсот into the Genitive, you have to decline both halves of the word. The first half шесть becomes шести, and the second half сот is the Genitive plural of сто.

Does the noun калорий change its case because the number is in the Genitive?

Yes! When a number is in the Nominative case, it forces the noun into the Genitive. But when the number itself is in an oblique case (like the Genitive шестисот here), the noun simply matches its case and stays plural. So калорий is Genitive plural to match the number.

Why is сахар (sugar) written as сахара?

The preposition из-за (because of) always takes the Genitive case. Since сахар is a masculine noun ending in a consonant, we add -а to make it Genitive.

Could I use больше instead of более in this sentence?

Yes, you could say содержит больше шестисот калорий. The word более means the exact same thing but sounds slightly more formal or written, which is very common when talking about facts, statistics, or nutrition. Both words require the Genitive case for the following noun or number.