#2. Your Personality and Mood
You already know that people eat fatty and sweet food when they get stressed out -- the snack food industry pretty much depends on this for half of their yearly sales. The simple explanation is that when we're in a bad mood we want to eat something that will make us feel good; the sciencey explanation has to do with how sugar and carbs can boost the levels of Serotonin in the brain. But, strangely, stress can also change the way food tastes to you.
In a somewhat diabolical 1998 study, scientists asked a group of people to each taste a sample of artificial sweetener, and then they went about stressing those people out. They first assigned them each a task of unscrambling a series of jumbled-up words, which might not sound very stressful, but the scientists deliberately designed half of these puzzles to be unsolvable. Oh, and there was a machine which blasted a horn into their ears at completely random intervals.
After this bout of torture, the group was then asked to taste another sample of artificial sweetener and rate how bitter and sweet this sample was compared to the first sample they took. The group rated it as being more bitter, and less sweet than the exact same stuff they ate before the scientists went about pissing them off.
"It's OK, those men can't hurt you anymore."
Does that mean that, because the stressed-out brain wants you to eat something sweet, it makes you perceive foods as being less sweet so that you'll eat more of it? The scientists don't take it that far, though it is interesting to note that strenuous physical exercise does the opposite -- when physically exhausted, you're more likely to taste the sugar in whatever you eat or drink. So if after a long run you chug some Gatorade and suddenly feel like somebody has shot you in the mouth with a sugar cannon, that's why.
And on top of all of that, scientists have found different people taste foods differently based on, not just their mood, but their overall personality. Different chemicals in your food react to different chemicals in your brain, thus the foods you like aren't just personal preference, they say something about how your brain works. Depressed people can't taste sweetness as well, people with panic disorders don't taste bitterness as strongly as others.
Which means all Robert Smith can taste is corn.
So keep that in mind the next time you shove something in a friend's face and say, "OH MY GOD YOU HAVE GOT TO TRY THIS ITS SOOOOOOO GOOD" and after taking a bite they ask if you're high. It's not just personal preference, they are literally tasting it differently than you.
Once again, this is one that seems obvious at first. Of course it matters how food looks -- there are people who work as food stylists whose job it is to dress up food for ads and menu photos. But color can affect your taste buds in all sorts of unexpected ways.
For instance, it's been found that the color of the glass in which the drink is served has the ability to alter how the drink itself tastes. Thanks to our odd tendency to unconsciously associate fiery colors with heat, one study found that drinkers perceived drinks served in yellow and red containers as being hotter than those (same) drinks served within blue and green containers. Other studies have shown that the color of the liquid itself influencing how sweet, sour, or bitter you find it to taste, with green having the effect of making sweet drinks seem even sweeter, while yellow makes them seem less sweet. Take a sour drink and change the color to yellow or green, and it'll taste less sour to you.
"Mmmm ... what is that, goat's blood?"
It's all about expectations. Ever wonder why "hot" cinnamon candies are always red? A hot blue candy would just be... wrong. Which brings us to the weirdest experiment in this article, a famous 1970s study mentioned in the book Fast Food Nation.
The participants were placed in a room and asked to simply eat a meal consisting of steak, french fries, and peas, all of which the experimenters provided. To the untrained eye, the food was completely normal both color-wise and taste-wise, which should have aroused suspicion considering these people knew they were part of an experiment. We'd have expected the scientists to come out at the end and announce, "Congratulations, everything on your plate has touched my balls! For science!"
"And that banana has been in Tony's ass. So fuck you."
But that wasn't it. Unbeknownst to the poor men and women eating this meal, the lights in the room were equipped with filters that hid the fact that all of their food had been dyed the wrong color. When they turned on the normal lights, the test subjects saw that the steak was actually blue, the fries were green, and the peas were red. Luckily for the scientific method, the reaction from the participants was fairly hard to misinterpret: they suddenly became violently ill at the sight of what they'd just eaten.
For more things outside your control, check out 6 Weird Things That Influence Bad Behavior More Than Laws and 6 Factors That Secretly Influence Who You Have Sex With.