The Wall Street Journal published a great article a couple weeks back, which described how humans react to food differently. The picture below describes two of the systems that our body uses when we consume foods, or are around them (you can click here for a better view of the picture). The hedonic system is a system in the brain that mediates the role that sensory pleasure (smell, site, sound) plays in eating (source). It’s the system that stimulates our hunger and desire to eat. The homeostatic system is the system in our brain that kicks in when we eat to fullness, and which sends signals to our brain to help us stop eating.
Research indicated that after a large meal obese individuals reacted more hedonistically to a large, sweet, and fatty dessert, despite being full, whereas the more lean individuals didn’t allow their hedonic system to take over, and instead their homeostatic system kicked into full gear and helped them overcome the desire to eat the dessert.
“When obese people see high-calorie foods, a widespread network of brain areas involved in reward, attention, emotion, memory and motor planning is activated, and all the areas talk to each other, making it hard for them to resist,” says Susan Carnell, a research psychologist at the New York Obesity Research Center at Saint-Luke’s-Roosevelt Hospital and Columbia University and one of the investigators.
“If you are of normal weight, your homeostatic mechanisms are functioning and controlling this region of the brain,” says lead investigator Dana Small. “But in the overweight group, there is some sort of dysfunction in the homeostatic signal so that even though they weren’t hungry, they were vulnerable to these external eating cues.”
Sadly research also showed that individuals who were once obese, then lost the weight, still had this same issue of the hedonic system taking over. Might this be why it’s so difficult to take off weight?
This article also talked about how obese individuals have a heightened sensitivity to food cues, but they may not necessarily eat more than lean individuals. The heightened sensitivity, however, may prompt them to think of food more often, and do more snacking.
Personally I know there have been times when I have seen something like chocolate cake after a large meal and I still want a piece (and sometimes have a piece), regardless of being full. I know I’m not obese, so what’s the deal? I do believe I have really great self-control, so perhaps if I was obese it would be more difficult for me to pass up that piece of cake. Who knows. I’m sure the food marketing industries, after reading this research, are already starting to think of more ideas on how to lure in their customers (as if their iconic images on TV aren’t already bad enough…).
Next week I’ll be posting some recaps of my time in Pittsburgh! I have a lot of fun pictures and stories to share. I’m happy to be heading back to Columbus this afternoon, but I’m sure I’ll be back here soon!