I recently attended a seminar on Food, Stress and the Brain that helped me see more clearly what we are really doing to our gray matter when we opt for "pizza, pop, and pop-tarts." Our three mechanisms for regulating appetite are rapidly thrown off-kilter when we indulge in high-fat, high-sugar, high-sodium foods.
- The first mechanism, the homeostatic system, is like our car's fuel pump. Using hormones, it signals us to eat when we are low on nutrients and stop when we are full. Insulin and leptin play a vital role here as they carry feedback to the hypothalmus in the brain.Unfortunately, eating junk food not only causes insulin resistance, but also leptin resistance. Our bodies can be flooded with these hormones but be unresponsive. (Having high triglycerides actually impairs the transport of leptin) The brain, like a conscientious mother, can be screaming at her cell children to "clean up this mess," but the more cluttered the "home," the more they tend to tune her out. She increases her messages (i.e. sends out more leptin and insulin) and the cells resist even more.
- The hedonistic system is all about pleasure. When we eat food, we feel good. As a survival mechanism, this system rewards us for nourishing ourselves and it punishes us when we starve. This mechanism is what keeps infants nursing when they are so weak and tiny. The key player here is dopamine. When a food is perceived as pleasurable, dopamine is released in the brain, encouraging us to keep eating until we are full. At that point, leptin and insulin kick in, shutting off dopamine. But new hyper-palatable foods full of MSG and artificial flavors and colors keep the dopamine response revved up and over-ride homeostatic cues that stop the drive to eat. (That is why you can't have just one Doritoes chip.)
- The adrenal system operates not in response to food, but rather, in response to stress. But if we feed our stress with comfort foods, we will throw the hedonistic and homeostatic systems out of whack. See, when the adrenal glands release cortisol, they are trying to prepare the body for "fight or flight." Eating helps the body prepare. Therefore, cortisol is designed to increase the salience of comfort foods. But today's comfort foods contain too much sugar and bad fat. So they taste really good, but they don't nourish. In other words, they increase dopamine and contribute to leptin and insulin resistance, causes our body's appetite-regulating mechanisms to mal-function. In the meantime, cortisol triggers the storage of abdominal (visceral) fat and initiates systemic inflammation
- Stabilize blood sugars: By satisfying the human sweet tooth with fruits instead of refined sugars, we lower blood glucose and prevent or reverse insulin resistance.
- Lower glycemic index: Raising our fiber intake through vegetables, fruits, legumes, grains and seeds, reduces storage of visceral fat, improves leptin receptivity and improves blood sugar stability.
- Limit high-fat foods: Eating healthy omega 3's (such as those found in flax and chia seeds) preserves brain function, while consuming unhealthy fats (such as those in fast foods) triggers cravings and addictions.
- Decrease cortisol-induced inflammation: Eating anti-oxidants (lots of colorful produce) may not relieve stress, but it can undo the damage stress causes.
To your health and happiness,