While sedentary lifestyles and overeating continue to be selectively blamed as the sole determinants of the obesity epidemic, various researchers continue to explore the global map of the phenomenon.
For many obese people, the solution is far from being a simple matter of willpower . However, beyond personal motivation to be healthy, the modern world is radically opposed to our physiology. Multiple factors determine our eating behavior and ultimately the food choices we make. Let’s discuss the chemical senses of smell and taste.
The smell
By smelling food we detect the molecules released into the air by that food. The problem is that both repeated colds and constant pollution deteriorate the olfactory receptors and the damage accumulates over the years.
The aroma of a food is essential for eating behavior . It is capable of stimulating our hidden memories, as happens to Proust, or triggering the pleasure and reward system. In this way, the smell of high-calorie foods can direct us to look for food. For example, our sense of smell is affected by spending long hours in highly polluted environments. This generates a sensory disorder that increases the risk of diseases such as obesity, but also anxiety. Losing your sense of smell has a great impact on health, not just depression: weight gain. By diminishing the pleasure of eating, people can often overeat.
On the other hand, overweight and obese people have a greater perception of food aromas. Obese people have a sensitive sense of smell compared to lean people , especially after they have eaten. Furthermore, the areas of the brain that process information related to odors are strongly connected to those that regulate hunger and satiety in the brain. Unfortunately, until now it is difficult to know if the differences in the perception of aromas are caused by obesity or are the result of suffering from this disease.
Taste
This chemical sense is essential in the regulation of appetite. The taste buds of the tongue are unique like each one of us. A taste may be too intense for one person, and for another it may be almost undetectable. In fact, people can absolutely differ in how satisfying and filling an ice cream is, and thus their perceptions may be a major determinant of body weight. Taste is invariably associated with different neural patterns in the insula, the primary sensory cortex. If a person cannot differentiate between tastes, this impacts how much they eat and whether they activate or inhibit the pleasure and reward circuitry. In fact, altered eating patterns are associated with changes in the insula’s ability to classify different tastes.
The relationship between taste and intake has already been demonstrated, what remains to be resolved is the causality as in the case of smell.
Does a decrease in taste sensitivity to perceive fat generate excess consumption and a greater preference for it? Or maybe part of it depends on genetics and then this is modulated during pregnancy and the first years of life? Some authors believe that taste preferences can be manipulated, even during youth.
Obese people live in a different sensory world. Obese boys perceive tastes less intensely. For example, sweet. Is it a cause of obesity or a consequence of it? An interesting case is that of people undergoing bariatric surgery. Before surgery, they react less intensely to sweet tastes than their thin counterparts. It is believed that the excess of food would be to compensate for the less satisfaction caused by less detection of taste. The overstimulation of tastes would generate saturation of the taste receptors and less perception. After surgery, many patients report changes in taste.
It was recently discovered that fat is the sixth taste (the others being salty, sweet, bitter, sour, and umami). It was called an oil taste. People who do not perceive the taste of fat eat more. Conversely, the ability to perceive fat is associated with satiety. If this mechanism fails, the tendency will be to increase the weight.
Although the factors that cause obesity are much more complex than taste or smell, the senses are the gateway . So good news: changing your diet could reset your preferences. If you consume less fat, then your ability to detect it will be greater and you will consume less fat and therefore fewer calories. And if you also eat using all your senses, those foods with lower levels of saturated, trans fat, salt, and sugar will improve your sensory performance. Your brain and your insula will receive better information and it will be easier for you to stop.