Palatability, Satiety and Calorie Intake

 discusses a study titled “A Satiety Index of Common Foods” by Dr. SHA Holt and colleagues.

This study, along with many others, suggests that focusing on simple foods that have a lower energy density leads to greater fullness and less subsequent food intake, and conversely that highly palatable energy-dense foods promote excessive food intake.  Potatoes, sweet potatoes, meats, fish, vegetables, fruits, rice and beans are foods with a moderate level of palatability and energy density, and are consequently helpful for weight loss and maintenance.  Conversely, baked goods, candy, ice cream and fried foods have the lowest SI, reflecting their extreme palatability and energy density.  These are exactly the same foods people eat to relieve stress, which reinforces the fact that they are hyper-palatable and hyper-rewarding.  In my opinion, these are among the most fattening foods, and the obesity literature as a whole supports this.

Read Stephan’s full post here.

I wouldn’t be surprised if this relationship was in some way an effect of missed dopamine predictions.  I am currently reading How We Decide by Jonah Lehrer.  He discusses how, after successfully learning an action to gain a reward, our brain releases dopamine in anticipation of the reward when we repeat that action.  This means our brain learns patterns and reacts in expectation of those patterns.  But, if that action response changes and no longer provides the same reward, our brain changes to no longer release dopamine.  So if you are throwing back peanut-butter cups, each time anticipating that super-sweet reward, your brain releases dopamine as soon as you reach for the next bite, before you even open the wrapper.  What would happen if you unwittingly grabbed a chunk of sweet potato that felt exactly like the candy?  Total let-down on taste resulting in a reduced dopamine response.  It’s a stretch, but I’ll bet you could break the streak of over-eating.

Cravings

Thorin Klosowski of Lifehacker discusses the definition of cravings, both physical and psychological, and how to turn them from a negative reward response into a positive and useful tool.

Psychological cravings include the feeling you get when you suddenly realize you want a Sloppy Joe or an entire bag of salt and vinegar chips. Two systems in our brains create and tell us how to react to cravings:

  1. First, the reward system identifies a target and causes the brain to release dopamine. This makes the brain believe it will get happiness or pleasure from what you’re craving. This desire for immediate gratification blocks your prefrontal cortex from weighing your long-term goals against the craving. You know the classic image of the angel and the devil on the shoulder? That’s essentially your brain when you are deciding if you’re going to fold to the pressure of a craving. Your craving is the devil, only thinking about short-term rewards, and the angel is your prefrontal cortex, pleading for you to consider the long-term ramifications.
  2. Next, your body releases stress hormones that make you feel discomfort or pain. The stress essentially tricks the body into believing the only way to feel better is to succumb to the craving.

According to Dr. McGonigal, the brain can learn to attach the promise of reward to almost anything. If your brain believes that something is going to make you happy, your brain can initiate the craving response.

Your instinctive reward system is designed to make you pursue or chase a goal. If you’re trying to start a new habit you want something less abstract than “being healthy” to chase after. Using those cravings to force yourself into accomplishing goals is a great way to provide the temporary reward system needed to establish a long running habit.

There was discussion of this reward response in the book Why Zebra’s Don’t Get Ulcers by Robert Sapolsky.  It’s part of the stress response.  I don’t have the book with me to reference, but I recall a study where the brain activity of mice was observed in an experiment where the mice could press a lever to get a reward.  The part of the brain associated with the pleasure of receiving the reward was activated upon pressing the lever – in anticipation of receiving the reward.

I try to recognize cravings.  When I crave a trigger food (something not part of my planned diet that will likely lead to fat gain), I try to remember the last time I gorged on junk food and I focus on the disgusting feeling I had after the indulgence.  I also have developed a craving for my workouts.  I try to direct my stress response into anticipation of my next weight lifting session.  Then, when it’s “go time”, I unleash my fury on the iron.

Get the full story on Lifehacker.