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Key points
- The desire for foods rich in sugars and fats is an ancestral trait.
- Consuming fatty and sweet foods leads to the rewiring of reward circuits in the brain.
- Breaking of these circuits requires behavioral and psychological approaches.
According to the Old Testament, the first human sin was eating. Adam and Eve could not resist the temptation to eat the forbidden apple because they were influenced by evil. Today, overeating remains one of the primary mistakes made by humans that cannot be attributed to Satan. The widespread availability of high-calorie food has led to overconsumption, contributing to the alarming prevalence of obesity worldwide. The high prevalence of obesity in children, as well as in adults, is a concerning indication of worsening health problems that governments will have to struggle with in the future.
However, interest in fatty and sweet foods was a beneficial evolutionary trait for our ancestors, who frequently faced food scarcity. Our hunter-gatherer ancestors were capable of consuming nutrient-dense and energy-rich foods to store energy as fat tissues for times of food shortage. The main problem is that we have the same genes as our ancestors, but food availability is not the same as during that time. It seems that consuming food three times a day is a relatively recent development in human history, likely emerging after the agricultural age and increased food availability. Some researchers believe that this shift in dietary habits may have adverse health effects on humans. Researchers show that fasting has a beneficial effect on human health and lifespan, indicating that the body responds positively to reduced food intake.
Sugars and fats recruit reward circuits in the brain and force us to seek out these foods.
Overconsuming sweet and fatty food is attributed to their palatability and irresistibility. Taste stimuli in the mouth stimulate mesolimbic circuits to release dopamine in the brain's ventral striatum, which is responsible for emotion and reward. The interaction between the ventral striatum, the amygdala, and the hippocampus causes the translation of emotions into behavior, such as seeking out food to recreate a certain feeling. Repetition of these eating habits rewires the mesolimbic circuitry, leading to increased liking and desire for more food, resembling addictive behavior.1
However, recent findings propose more powerful brain circuits that generate the desire to consume high-calorie foods using animal models. Studies in rodents indicate that palatability and taste alone are not enough to increase food intake in response to food rich in fats and sugars. So, the oral sensory aspects of food are considered less important than the nutritional value of food to force the subjects to consume high-calorie foods. These researchers have shown that sensory vagus stimulation by food, when it reaches the intestine, recruits the nigrostriatal circuit in the brain to release dopamine into the dorsal striatum. Stimulation of vagal sensory neurons by fats and sugars ultimately leads to actively seeking stimuli that activate this circuit in the brain. These findings propose that post-ingestive fats or sugars play a role in the chemosensory stimulation of vagal sensory neurons in the gut and the activation of reward circuits in the brain as a gut-brain pathway.2
Over time, consuming food rich in fats and sugars triggers pleasure sensations in the brain, leading to harmful dietary habits such as cravings and the desire to eat more of them again and again. This leads to a futile cycle of overeating, food "addiction," and, ultimately, obesity. Additionally, these high-calorie foods disrupt other neural and hormonal mechanisms that control appetite, such as leptin and ghrelin, which worsens the desire for these foods.
What can we do?
1. Consuming a balanced amount of proteins in the diet
Proteins can have a major impact on breaking overeating behaviors created by high sugars and fats in the diet. Consuming sufficient amounts of proteins in the diet can contribute to a sense of satiety, decrease cravings, and assist with managing weight. Proteins also produce more thermic effects compared to sugars and fats in the diet. Low-calorie diets often cause muscle loss, and proteins keep the muscle mass. Muscle mass has greater thermogenic effects compared to other tissues, and the loss of muscle leads to dieting failure.3 Adding protein-rich foods like lean meats, poultry, fish, eggs, dairy products, legumes, nuts, and seeds into your meals and snacks can assist in breaking the cycle of overeating triggered by sugars and fats.
2. Physical activity
Although starting exercise stimulates appetite and desire to consume more food, regular physical activity, particularly endurance training, can help regulate craving and appetite. Endurance training, combined with adequate protein intake, helps maintain muscle mass and reduces cravings for high-fat and -sugar foods. Along with calorie-restriction diets, exercise can positively influence dietary habits and weight management.
3. Dysbiosis of gut microbiome and probiotics supplementation
A diet rich in fats and sugars can alter the composition of the gut microbiome, leading to an imbalance between beneficial and harmful microbes, a condition known as dysbiosis. Harmful microbes can promote metabolic dysregulation and inflammation, and have an adverse impact on cognition and appetite-control mechanisms, potentially contributing to overeating induced by sugars and fats. Therefore, supplementation with probiotics (beneficial live microbes) and prebiotics (dietary compounds that positively affect the microbiome) may have a beneficial impact on eating disorders and overeating.4
4. Other strategies to reduce the desire for foods high in sugars and fats
Mindful eating leads to more attention to our dietary habits and causes better food choices. Paying attention to eating and savoring each bite and taste of food causes a slowdown in eating and reduces overeating and cravings. Prevention of exposure to high-fat and -sugar foods in the home and workplace may help individuals to follow low-calorie diets. Instead, exposure to healthier food helps one to choose nutritious and useful foods.
Of course, the compulsive behaviors produced by the brain's rewiring of circuits require the support of a therapist who specializes in behavior change or cognitive-behavioral therapy. Over time, these strategies can rewire established circuits and change our eating habits.
References
1. Morales, I., & Berridge, K. C. (2020). 'Liking' and 'wanting' in eating and food reward: Brain mechanisms and clinical implications. Physiol Behav, 227, 113152. doi:10.1016/j.physbeh.2020.113152
2. McDougle, M., de Araujo, A., Singh, A., Yang, M., Braga, I., Paille, V., . . . de Lartigue, G. (2024). Separate gut-brain circuits for fat and sugar reinforcement combine to promote overeating. Cell Metab, 36(2), 393–407.e397. doi:10.1016/j.cmet.2023.12.014
3. Leidy, H. J., Clifton, P. M., Astrup, A., Wycherley, T. P., Westerterp-Plantenga, M. S., Luscombe-Marsh, N. D., . . . Mattes, R. D. (2015). The role of protein in weight loss and maintenance. Am J Clin Nutr, 101(6), 1320s–1329s. doi:10.3945/ajcn.114.084038
4. Turnbaugh, P. J., Ley, R. E., Mahowald, M. A., Magrini, V., Mardis, E. R., & Gordon, J. I. (2006). An obesity-associated gut microbiome with increased capacity for energy harvest. Nature, 444(7122), 1027–1031. doi: 10.1038/nature05414
