We eat the foods we like, and avoid the ones we don't. But why? And why do some people love foods that others despise? Our preferences stem from physiological traits that have evolved with our species. It started as a means for survival. Taste drives our appetite. We crave certain foods because our body needs them. Sweets are rich in energy-giving carbohydrates. Salt balances our body fluids and carries nutrition throughout the body. Bitterness and acidity are warnings of toxins and spoiled foods.
Nature is Amazing
Of course, our cave-dwelling ancestors didn't crave a Milky Way bar like, and most would have quickly spat out that cup of coffee. Taste has evolved in humans over time as a result of technological and cultural events. For instance, the ability to preserve foods through curing (salt) and brining (acid) changed our reluctance to ingest these basic tastes. We taught ourselves to like alcohol and coffee (fermented, bitter, and astringent beverages) because we found their effects pleasurable. People brought up with a diet of highly spiced foods have a much higher tolerance for it. Many of the body's natural defense mechanisms have been thwarted in the name of flavor.
In deconstructing flavor, we divide foods into four taste groups based on the sensory capabilities of our tongue: salty, sour, sweet, and bitter. But the basic elements of flavor are classified differently from culture to culture. Hot is an added taste sensation in China. India adds spicy and astringent. The Japanese term umami, meaning "delicious flavor", also called savory or succulent, has recently been accepted around the world as a legitimate taste element. At the University of Burgundy, researchers have isolated a taste receptor for fat. Some consider metallic a taste, especially after experiencing their tongue on the flag pole or accidentally chewing aluminum foil. There even those who identify neutral as a taste, as in water. The number of primary tastes is up for some debate, but there are a basic few.
Saltiness is mainly experienced in the presence of sodium chloride (NaCl). Sodium is necessary for physiological survival to keep the concentration of our body fluids at the correct levels. It helps our cells absorb nutrients, and it helps transmit electrical impulses to our nerves. Like sugar, it's possible that the craving for salt is a built-in survival reflex.
Sour taste seems to be innately unpleasant. This is by design, as soured foods, like spoiled milk and rotten fruit, tend to make us ill. But as children age, there tends to be a period in which the sour taste is highly prized (which explains the popularity of sour gummy worms).
Human babies respond to sugar quite early. The taste is innately pleasant because the calorie-rich carbohydrates are an essential energy source for humans.
Bitterness is meant to be a warning against toxicity. Sharp, disagreeable tastes occur as a natural indication of poison. Synthetic, bitter-tasting chemicals are commonly added to toxic substances like antifreeze and denatured alcohol to prevent accidental poisoning.
Scientists have recently isolated taste receptors that respond to glutemic acids, or glutamates. First found in seaweed, glutamates are used in the flavor enhancer monosodium glutamate (MSG). Some call it the fifth taste, while others still refer to it as more of a mouthfeel. It’s taste has been described in several ways, including meaty, savory, succulent, woodsy and earthy.
