Eating Disorder/Disordered EatingLifestyle

Appetite Responses to Stress

By August 21, 2019 No Comments

We all great stressed from time to time.  And some stress is essentially good; like the butterflies you might feel before an important interview or the pressure that motivates you to meet a deadline at work.  However, stress becomes a problem when it turns into a chronic issue and begins to negatively interfere with your daily life, personal development, and functioning. 

The natural stress response occurs when you encounter a perceived threat, like a dog charging at you while running.  During this response, the hypothalamus in your brain signals your adrenal glands, which sit on top of your kidneys, to release the hormones adrenaline and cortisol.  You know that rush you feel right after an immediate threat?  Yup – that’s caused by the surge of hormones being released.

Once the threat has passed, hormone levels return to baseline levels.  As adrenaline and cortisol levels drop, your heart rate and blood pressure return to normal and other body systems resume their regular activities.  But when stressors are always present and you constantly feel under attack, the stress reaction stays turned on.  The long-term activation of the fight or flight system and the overexposure to cortisol and other stress hormones can disrupt almost all your body’s processes, putting you at increased risk for many health problems, including:

  • Anxiety
  • Depression
  • Digestive issues
  • Weight gain
  • Headaches
  • Heart disease
  • Sleep disturbances
  • Memory and concentration problems

Some people are more susceptible to chronic stress, either due to genetics or a traumatic life event, like abuse or exposure to continued violence.  However, we are all going to endure stressful life experiences. Knowing how to deal with stress in a healthy way can decrease your risk for developing some or all the above complications. 

Stress management strategies include:

  • Relaxation techniques like meditation, yoga, massage, or deep breathing
  • Developing trusting and healthy friendships
  • Taking time for hobbies, such as reading, journaling, scrapbooking, or kayaking
  • Laughing with friends and loved ones
  • Spending time in nature
  • Seeking professional help when needed
  • Eating a healthy diet and getting regular exercise

So, let’s talk about how nutrition plays a part in the stress response.  During high stress, serotonergic activity in the brain increases, which leads to the breakdown of serotonin.  An important chemical and neurotransmitter in the human body, serotonin is thought to regulate mood, social behavior, appetite and digestion, sleep, memory, and sexual desire and function.  There is also a link between serotonin and depression, hence some individuals with severe depression being prescribed selective serotonin reuptake inhibitors (SSRI’s).  As the synthesis of serotonin decreases so does its precursor, tryptophan.  Tryptophan is an essential amino acid that helps the body make proteins and certain brain-signaling chemicals; like serotonin.  Depletion of tryptophan has been linked to increased depressive moods. 

One would think that eating a high protein diet would increase tryptophan, thereby increasing serotonin.  However, research has illustrated that eating a high carbohydrate, protein-poor meal causes parallel increases in the amount of serotonin released into brain synapses.  Insulin, which is released in response to carbohydrate intake, has little to no effect on tryptophan levels; however, it lowers plasma levels of large neutral amino acids, which compete with tryptophan for passage across the blood brain barrier.  This allows more tryptophan to enter the brain.  Therefore, carbohydrate rich foods increase brain levels of tryptophan more than high protein foods do.  Ever wonder why you’re happier after eating carbohydrates?  There’s your answer!  

Take home message?  During times of stress don’t limit carbohydrate rich foods.  You might be craving highly palatable foods (high sugar) due to the comforting effect we get from them.  It is okay to indulge!  However, also remember to include carbohydrates from whole grain sources, starchy vegetables, and fruit as well.

During times of acute stress, appetite is thought to be suppressed due to hormone changes.  However, during recovery from stress and with chronic stress eating is usually increased due to appetite stimulating effects of residual cortisol.  There is a link between cortisol, energy regulation, and weight gain.  It is thought that cortisol effects other stress response factors that directly impact appetite, like leptin, neuropeptide Y, and cytokines.  Individuals with chronic high cortisol levels tend to eat more and have more weight changes. 

Take home message?  Practice stress management strategies in order to control your cortisol levels.  This will alleviate poor eating habits, like nighttime eating syndrome and sugar cravings, which will help to manage your appetite and weight.

References:

Bray, G. A. (1985). Autonomic and endocrine factors in the regulation of food intake. Brain research bulletin, 14(6), 505-510.

Schaechter, J. D., & Wurtman, R. J. (1990). Serotonin release varies with brain tryptophan levels. Brain research, 532(1-2), 203-210.

Smith, S. E., Pihl, R. O., Young, S. N., & Ervin, F. R. (1987). A test of possible cognitive and environmental influences on the mood lowering effect of tryptophan depletion in normal males. Psychopharmacology, 91(4), 451-457.

Takeda, E., Terao, J., Nakaya, Y., Miyamoto, K. I., Baba, Y., Chuman, H., … & Rokutan, K. (2004). Stress control and human nutrition. The Journal of Medical Investigation, 51(3, 4), 139-145.

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