It is widely believed that there is an association between food and pain. People with chronic pain often struggle with their weight. How chronic pain affects eating behavior and body weight is still poorly understood.
Scientists at the Del Monte Institute for Neuroscience have explained that circuitry in the brain responsible for motivation and pleasure is impacted when someone experiences pain.
Scientists looked at brain responses to sugar and fat- using a gelatin dessert and pudding. They later altered the sugar, fat, and texture of the foods.
They found that no patients experienced eating behavior changes with sugar, but they did with fat. Those with acute lower back pain which later recovered were most likely to lose pleasure in eating the pudding and show disrupted satiety signals. On the other hand, those with acute lower back pain whose pain persisted at one year did not initially change their eating behavior.
Patients with chronic lower back pain reported that eventually, foods high in fat and carbohydrates, like ice cream and cookies, became problematic for them over time. Their brain scans also showed disrupted satiety signals.
When scientists performed brain scanning, they found that the nucleus accumbens—a small area of the brain mostly known for its role in decision-making— offers clues on who is at risk to experience a long-term change in eating behavior.
In patients who initially experienced changes in their eating behavior but whose pain did not become chronic, the structure of their nucleus accumbens appears normal. But in patients whose pain became chronic, their nucleus accumbens appears smaller.
Interestingly, the nucleus accumbens predicted pleasure ratings only in chronic back pain patients and in patients who became chronic after an acute bout of back pain. This suggests that this region becomes critical in the motivated behavior of chronic pain patients.
Smaller nucleus accumbens means a greater risk of developing chronic pain.
- Yezhe Lin et al., Chronic pain precedes disrupted eating behavior in low-back pain patients, PLOS ONE (2022). DOI: 10.1371/journal.pone.0263527