Human taste buds can detect five basic tastes: sweet, salty, sour, bitter, and umami. However, research suggests that there may be a sixth taste, known as the "fatty taste," which allows people to sense the presence of fats in food. This discovery could have significant implications for understanding and addressing obesity, as the ability to detect fats may influence food choices and eating behavior. The idea that "fatty" could be a taste is not new. In the fourth century BCE, the philosopher Aristotle noted in his work De Anima that oily qualities were part of the possible dimensions of taste. Later, in the 16th century, the French physician Jean Fernel also considered fat as a primary sensory quality in his medical text De Naturali Parte Medicinae. These early observations were based on philosophical reasoning and direct observation, rather than scientific experimentation. In recent decades, researchers have conducted extensive studies on the detection of fats in both humans and animals. These investigations have revealed that the fatty taste is not linked to a single receptor or signaling pathway but involves a complex system of lipid-sensitive receptors. In human taste buds, two glycoproteins, CD36 and GPR120 (also known as FFAR4), play a key role in detecting long-chain fatty acids. These proteins are also found in other organs, such as the liver and intestine, where they are involved in fat metabolism. Studies on the sand rat, a desert rodent that does not drink water, have shown that its taste buds express CD36, which helps it prefer water mixed with oily substances. This receptor is involved in detecting fats during fasting, while GPR120 is more active between meals, influencing the motivation to consume fatty foods. These findings suggest that the perception of fats is not only a conscious taste but also triggers unconscious physiological responses, such as the "cephalic phase" of digestion, which prepares the body for food intake. Research has also shown that people with obesity may have reduced sensitivity to fatty tastes. Clinical studies in countries such as Morocco, Algeria, and Lebanon have found that obese individuals, both children and adults, often have lower oral detection of lipids compared to non-obese individuals. This reduced sensitivity is linked to changes in the expression of the CD36 receptor, which can be influenced by dietary habits and environmental factors. Epigenetic modifications—changes in gene expression that do not alter the DNA sequence—may also play a role in this reduced sensitivity. Scientists are now exploring whether targeting these receptors could offer new ways to combat obesity. By enhancing the fatty taste through specific molecules that activate CD36 and GPR120 receptors, it may be possible to increase satiety and reduce overeating. Experimental studies in rodents have shown that activating these receptors can trigger the release of hormones that suppress hunger, suggesting a potential therapeutic approach. While these findings are still in the experimental stage, they offer a promising new direction for managing obesity without directly restricting food intake.