Overeating Just Makes You SAD! | (Seasonal Affective Disorder)

Happy Friday! How was your first week of July? How did you celebrate Independence Day, or Canada Day? (Was the gym open? KUDOS to you local gym if it was. Mine was closed so I ended up running outdoors, enjoying the weather and skipping my afternoon workout).

Today I want to share with you a project that I’ve worked on for a class. I found the findings quite insightful and share-worthy! It’s on the relationship between Seasonal Affective Disorder and Overeating…something we all struggle with from time to time is having the weather affect our moods, and a lot of times, I turn to food for comfort. It might trigger a binge. Enjoy my findings!

**this is a lot more formal than my usual writing style; I just wrote a paper for school on this topic after lots of research and thought it’d be insightful to share my findings!

Overeating Just Makes You SAD.

Dieting makes you sad, so would overeating make you happy? Not necessarily, especially if it is caused by feelings of depression. Overeating poses a problem making you just as miserable. Seasonal affective disorder plays a huge role in overeating, also referred to as the “winter munchies”. Let us embark on what Season affective disorder is, its possible causes, and its relation to overeating.

Seasonal Affective Disorder affects approximately 6% of the US population (Targum & Rosenthal, 2008) and carries the same symptoms as depression: feeling hopeless, changing sleep patterns, lacking pleasure in things that used to be interesting, and worst case scenario, feeling suicidal. The only difference between SAD and depression is that the diagnostic criteria for SAD include 2 consecutive years of a depressive phase starting at approximately the same period and ending approximately the same period, and the depressive episodes grow longer than the non-depressive episodes as time goes on. SAD used to be categorized as a separate mood disorder in DMS-4, however in its most recent revision in DSM-5, it was sub-categorized under Major Depressive Disorder (American Psychiatric Association, 2013).

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Seasonal affective disorder is more common among countries located further away from the equator, as the number of hours for daylight versus night time changes more dramatically the closer the country is located to the poles. Countries who live near the equator get roughly the same number of daylight hours year-round. In fact, statistics show that Russia has 16.2% SAD (Booker et al., 1991) whereas the Philippines has 0% SAD (Ito et al., 1992). This is due to the change in a body’s circadian rhythm in accordance to sunlight. The circadian rhythm regulates sleep, mood and energy and the lack of sunlight during the winter months causes a shift in serotonin levels, which is the main hormone affected by SAD. It is the hormone responsible for good moods.

A study in 2016 proved that this hormone plays a crucial part in SAD. A group of researchers measured the serotonin levels of two groups: 17 diagnosed with SAD and 23 that were not. Levels were recorded in both summer and winter, and the results were compared. What they found was that the measured serotonin transporters in both groups had the same amount as each other in the summer, but in the winter, the non-SAD group had lower amounts of transporters than the summer, and the SAD group had the same levels year round. The serotonin transporters in the non-SAD group were lowered to adjust to the lack of sunlight in the winter to account for the seasonal changes (thus, it allowed the post synaptic cells to receive serotonin more readily due to the reduced reuptake levels to the presynaptic cell) whereas those diagnosed with SAD had the same amount of serotonin transporters in the winter as they did in the summer. This meant less serotonin was received by the post synaptic cell and more were reuptaken by the presynaptic cell (Mahon et al., 2016). Thus, they concluded that individuals with SAD have an impaired ability to adjust their serotonin transporter levels in accordance to the change in daylight. Furthermore, the severity of the depressive symptoms is directly correlated with the number of transporters available. The more transporters, the more severe the depressive symptoms.

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SAD does have its evolutionary values. Warm temperatures and a richer food environment allows human species to prosper during spring and summer months, making it favorable for raising an offspring. Lethargy and low moods dominate during fall and winter, which could be hypothesized as being a poor time to procreate because of the lack of resources. This could explain why humans as a species prefer to give birth in the spring when conditions are optimal for raising a child; to do so they must conceive during the winter months. The females, during pregnancy, experience weight gain, lethargy, and mood swings during these winter months and give birth in the spring (Davis & Levitan, 2005). This explains why evolutionarily, we have lower moods in the winter, and why women are more vulnerable to SAD.

Overeating is common among those with depression. When it comes to coping with negative feelings, numerous individuals turn to food. In a study of 122 participants diagnosed with SAD, researchers determined specific months in which the most binge eating behaviour occurred. November to March was reported as the highest, and almost none in the other months (Donofry et al., 2014). This finding is not surprising, as the days are shorter in the northern hemisphere during those months. The brain registers emotional pain in the same area as it does with physical pain. Opiates are a painkiller, and because sugar is an opiate, sugar is used to destress. Sufferers often turn to sugar (in the form of highly palatable junk food such as donuts, candy, etc.) for emotional comfort to escape the discomfort (Ouwen et al., 2009), literally “eating their feelings away”. Initially the rush of glucose supplied to the brain may remedy the negative feelings, but ultimately, the poor food choices lead to long-term negative health consequences such as obesity (Sonneville et al., 2013) and type two diabetes. In addition, sugar spikes blood insulin levels, leading to fatigue and unstable moods which further contributes to depression and the urge to reach for sugar for that instant energy again; driving a vicious cycle. Overeating may become an addictive behavior, especially because sugar activates the reward system at an intensity equal to or greater than drugs (Ahmed et al., 2013). In repeated high dosages, overeating has the potential to turn into a full-blown food addiction (Avena et al., 2008).

All in all, there is no doubt that SAD has its relation with overeating due to its primal roots and biochemical reaction to serotonin. SAD sufferers reach for sugar to remedy negative feelings which provide only a temporary solution. Overall, while overeating can occur in cases without depression, there is no doubt a strong correlation between the two, one causing the other and vice versa.

I’d love to hear your thoughts! Do you suffer from SAD? How do you get through it? Where in the world do you live?


Ahmed, S. H., Guillem, K., & Vandaele, Y. (2013). Sugar addiction. Current Opinion in Clinical Nutrition and Metabolic Care,16(4), 434-439. doi:10.1097/mco.0b013e328361c8b8

Avena, N. M., Rada, P., & Hoebel, B. G. (2008). Evidence for sugar addiction: Behavioral and neurochemical effects of intermittent, excessive sugar intake. Neuroscience & Biobehavioral Reviews,32(1), 20-39. doi:10.1016/j.neubiorev.2007.04.019

Davis, C., & Levitan, R. D. (2005). Seasonality and seasonal affective disorder (SAD): An evolutionary viewpoint tied to energy conservation and reproductive cycles. Journal of Affective Disorders, 87(1), 3-10. doi:10.1016/j.jad.2005.03.006

Donofry, S. D., Roecklein, K. A., Rohan, K. J., Wildes, J. E., & Kamarck, M. L. (2014). Prevalence and correlates of binge eating in seasonal affective disorder. Psychiatry Research, 217(1-2), 47-53. doi:10.1016/j.psychres.2014.03.012

Mahon, B. M., Andersen, S. B., Madsen, M. K., & Hjordt, L. V. (2016). Seasonal difference in brain serotonin transporter binding predicts symptom severity in patients with seasonal affective disorder. Brain, 139(5), 1605-1614. doi:10.1093/brain/aww043

Mcclung, C. A. (2007). Circadian genes, rhythms and the biology of mood disorders. Pharmacology & Therapeutics,114(2), 222-232. doi:10.1016/j.pharmthera.2007.02.003

Ouwens, M. A., Strien, T. V., & Leeuwe, J. F. (2009). Possible pathways between depression, emotional and external eating. A structural equation model. Appetite,53(2), 245-248. doi:10.1016/j.appet.2009.06.001

Sonneville, K. R., Horton, N. J., Micali, N., Crosby, R. D., Swanson, S. A., Solmi, F., & Field, A. E. (2013). Longitudinal Associations Between Binge Eating and Overeating and Adverse Outcomes Among Adolescents and Young Adults. JAMA Pediatrics,167(2), 149. doi:10.1001/2013.jamapediatrics.12

Targum, S. D., & Rosenthal, N. (2008). Seasonal Affective Disorder. Psychiatry (Edgmont)5(5), 31–33.