Mayonnaise is frowned upon

While mayonnaise used to be a staple in every home, in recent years millennials have stopped buying and eating it. Even if they like it, many of them would prefer to use more eye-catching and expensive condiments like avocado in their food.

Chances are, if you're eating at a trendy spot frequented by millennials, you won't find mayonnaise listed on the menu. And don't waste your time looking for it in the fridge.

Raisins were fine when they were kids

According to Harry Overly, CEO of Sun-Maid's Raisins, millennials have become the biggest problem for the raisin industry. Apparently, the only people eating raisins these days are older generations or people with young children.

The raisin industry is now experimenting with a new marketing strategy, targeting millennials' nostalgia for their childhood, but it doesn't seem to be working yet. While millennials would prefer to spend their money on other foods, another reason for the decline in raisin sales is that they contain too much sugar for many of today's ultra-healthy diets.