During the past 20 years, there has been a dramatic increase in obesity, which has added up to over a third of American adults tipping the scales — their taste buds carefully trained by the food industry. The country’s children are catching up, too. In the last 30 years, the rate of obese children and adolescents has respectively doubled and tripled, adding up to 12.7 million obese kids who will one day grow into obese adults. 
In part, high rates of obesity may be attributed to the number of chemicals that make up today's food flavor profiles. Fifty years ago, there were less than 700 flavor chemicals meant to mimic naturally occurring foods on the market. In today's America, there are more than 2,200. A once simple system of nutritional nourishment has been toyed with by a complex, chemically-altered language that our bodies are now struggling to communicate with.
“We could live in a world where food tastes very good and the people who eat it are not fat,” food journalist Mark Schatzker explains in his new book The Dorito Effect: The Surprising New Truth About Food and Flavor, which describes how food flavors are changing and how that might affect their future. “Synthetic flavor might be the salesman in the fancy suit that sells our brains the calorie-rich carbs we’re eating so much of, but real flavor — authentic versions produced in nature — is our only road to salvation. I will say it again: Real food is our salvation.”
Humans have between 2,000 to 5,000 taste buds located on the back and front of the tongue. Each of those have 50 to 100 taste receptors that are designed to process five different flavor profiles — sweetness, saltiness, bitterness, sourness, and umami. When a beer pours into your mouth and hits your tongue, it spreads over different taste receptors, which detect interactions with the drink's molecules, ultimately forming a flavor.
Flavor profiles are put in place for a reason. Sweetness identifies energy-rich foods, saltiness detects the presence of sodium ions, and sourness is the only receptor to respond to acidity in another part of the body — your spinal cord. Umami is a one of the newest tastes; it processes savory, meaty, and appetitive tastes. Meanwhile, bitterness is your most sensitive taste receptor, designed to perceive sharp, disagreeable tastes likened to poison.

On average, people lose half of their taste receptors by the time they turn 20 years old. Each year, more than 200,000 people visit the doctor for problems with their taste or smell, according to the National Institute on Deafness and Other Communication Disorders. As a result, losing your sense of of taste can lead people to add too much salt and sugar to make food taste better. This can eventually lead to some serious health conditions, including high blood pressure or diabetes.As you age through the years, the way your senses translate information about the world fades. The way you hear, see, smell, touch, and taste, will dull and lose sharpness, making it difficult to differentiate details, according to the National Institutes of Health. In order for your brain to process a signal, a minimum threshold must be stimulated. But as you age, that minimum threshold increases and requires higher levels of stimulation to send signals to your brain.

Nothing Tastes As Good As Skinny Feels

The same phenomenon is taking place with obese children. Taste buds have changed in response to the common American food supply, and may play a volatile role in the childhood obesity epidemic. In 2012, German researchers were the first to make the connection when they published a study in the Archives of Disease in Childhood, which tested normal and obese children’s taste buds.
Researchers measured the taste buds of 193 children between the ages of 6 and 18 — half of the group was normal weight and the other half was clinically obese. Each child’s tongue was lined with 22 taste strips, representing five types of tastes with four levels of intensity per taste type — and two blank placebo strips. The children got a point for every taste they were able to identify, adding up to 20 total possible points. The researchers found obese children had a significantly more difficult time distinguishing between the tastes, and averaged a score of 12.6. They rated most of the high-intensity taste strips as weaker, when compared to the normal weight kids, indicating their taste buds were duller.
The study’s authors said that while we’re all born with individual taste preferences, which are influenced by genes, age, and gender, while also being exposed to a variety of tastes at different points in our life, an obese person’s hormones are powerful enough to mute taste sensitivity. When you eat, insulin rushes through your bloodstream to balance out the blood sugar levels rising in your system. Obese people tend to have consistently elevated insulin levels for longer periods of time, which researchers hypothesize weakens the cells’ receptors, including those on the tongue.  
An example of this comes from an Australian research team out of Deakin University, who gave 80 volunteers milk with a range of different fatty acids. Those who were the best at identifying levels of fat correctly had one thing in common — they were of normal weight. The study, published in the British Journal of Nutrition, found the taste of fat triggered a response in the body’s appetite control system.
Their taste buds were hypersensitive to fat because their body was wired to recognize when they had drank enough. Unfortunately, the researchers believe people's taste buds are becoming desensitized because of the modern American diet. People have become obese because they've been eating fatty foods that have desensitized their taste buds.

Re-Engineering Healthier Tongues

Perfect red tomatoes from the supermarket taste like tap water and a simple roast chicken is doused with tons of seasoning. The amount of seasoning Americans use has tripled in the last 20 years, and it’s because our taste buds have adapted to a new palate. But in naturally occurring foods, flavor seldom grows without nutrition. In order for humans to climb their way out of the obesity abyss, they must develop healthier palates.
The tongue is composed of living cells, which can be taught to love the vegetables you may hate right now. By improving agriculture, humans can reengineer their taste buds to develop the healthier and more natural flavor profile our ancestors were once born with. Taste perceptions can even change with weight loss.
For example, when Dr. John M. Morton, chief bariatric surgeon at Stanford University Medical School, began to see a change in how some of his obese patients tasted food, he decided to investigate. His research, presented at Obesity Week 2014, compared 55 obese patients undergoing bariatric surgery to 33 health non-obese people who never had surgery. All participants were given taste tests, and 12 months after surgery, 87 percent of formerly obese patients had new taste preferences. 
The tongue may be the key to reversing the obesity epidemic if taste buds can be retrained properly. Schatzker recommends giving a child a piece of fruit so they can learn to eat for the natural sweetness in foods and not added table sugar. Raising children to have healthier taste buds can even start in the womb. Studies have shown that infants who are exposed to healthy food flavors through amniotic fluid and breast milk tend to enjoy healthier foods as children, and eventually as a new generation of adults.
Source: Weigand S, Krude H, Hummel T, and Overberg J. Differences in taste sensitivity between obese and non-obese children and adolescents. Archives of Disease in Childhood. 2015.