Hunger Versus Craving, Belly Versus Brain

Are you feeding your brain or your belly? Are you really hungry or do you just “crave” something? Hunger and cravings are both feelings and experiences that are driven by complex signals in our brains. The gut is our second brain. It is important for those who don’t have weight issues to be empathetic toward those who struggle, and it is important for those overweight individuals who feel like failures to understand that complex biological factors play a role in their weight gain. These factors are sometimes difficult to treat but not impossible.  

Hunger is controlled by gut-brain neurochemical signals originating in the stomach that tell your brain you are hungry or full. Hunger is a physical feeling that doesn’t go away and intensifies if you do not eat. Typically, hunger is not a craving for one specific food; any kind of food will satisfy the need.

There are receptors throughout our digestive tract that detect the presence of nutrients. When nutrients are not present, hunger hormones, such as ghrelin, are produced that send a signal to the hypothalamus of our brain—the part that controls hunger and thirst. This signal then creates the desire to eat.

As we eat, other hormones are released that tell the hypothalamus to produce neuropeptides and special protein substances that suppress hunger. When we start to become full, additional hormones (such as leptin, which is produced in our fat cells) send signals to our brain that tell us to stop eating.

Insulin, which is secreted by the pancreas, also is released when we eat. When we gain weight, our body overproduces insulin and leptin, and eventually, our brain becomes less sensitive to these hormones, impacting our feelings of fullness and causing more hunger. It becomes a vicious cycle.

Alternatively, the brain reward process is the neurochemical signal that gives the feeling of pleasure or joy from food. It is usually emotional and is triggered by thoughts, visual stimuli, stress, lack of sleep, sadness, anger, or boredom. It usually creates the desire for a specific type of food. The brain reward process involves psychological factors, such as enjoyment and pleasure neurochemicals that many times overpower our gut-brain system.

The endocannabinoid system of brain reward consists of signaling molecules that help the body maintain homeostasis, a stable internal state. It affects mood, appetite, stress, sleep, and more. The opioid system of brain reward controls pain, reward, and addictive behaviors. Both systems are involved in the want for and the like of food, which then ramps up our desire to find and get food, which leads to the pleasure of eating. These systems overlap in the part of the brain that controls motivation and reward. It has been shown in studies that when we eat foods high in bad fat, salt, and sugar, there is increased activity in these two systems.  

Cognitive control processes are the final processes that control eating. A food craving is an intense desire for a particular food, such as chocolate, ice cream, french fries, pizza, and cookies. Research has shown that there are differences in brain activity between people who crave food regularly and those who don’t. Brain imaging studies show greater activity in the brain reward areas when those with cravings see or eat chocolate—even when they see photos of food—compared to those who do not have cravings. People who are obese generally show more reactivity to food cues: pictures and videos of food as well as the sights and smells of real food.

Despite how complex the brain is when it comes to hunger and cravings, we do have cognitive control, but this control is more difficult to maintain when we are exposed to stressful situations and stimuli. Our current environment of busy lifestyles, non-stop social functions, constant electronic stimulation, readily available processed foods, fertilizers, and genetically modified food has made it difficult to maintain cognitive control. Food manufacturers know exactly what to put in their food to make people crave and want to eat more of their products.  

So what can be done? First, understanding that obesity is a complex disease and that there are powerful biological and environmental forces that trigger us to overeat can help those who are struggling with weight issues to not feel ashamed. Additionally, identifying the control processes described in this article and understanding them is a powerful tool. Being aware of fullness/true hunger versus cravings and setting realistic, smaller goals will increase success and improve confidence levels, which then can help with cognitive control and behaviors.

People trying to lose weight and trying to become healthier are not failures if they don’t succeed. There are many obstacles. This complex gut-brain system includes neurohormones and peptides (cholecystokinin, GLP-1, peptide-1, leptin, peptide-YY, ghrelin) and varies from person to person because of individual makeup, biology, and genetics.

There is nothing wrong with seeking professional help for accountability, education, supplements, or even medications. Don’t guess, don’t diet, and don’t use prescription medications without knowledge and professional help. Be safe when trying to lose weight. Remember, you are not alone. Don’t be afraid to reach out for help and make changes in your life that should last forever.