Typically, when we hear “You are what you eat,” we think of the link between diet and physical health. However, we now know that what we eat also has a powerful impact on our mental state. It is believed that as much as half of what we eat feeds our brain. It’s indeed quite a greedy organ! With this in mind, it is clear that diet can impact our thoughts, emotions, memory, self-control, and other aspects of mental functioning.
Sugar and the Brain
When we ingest a lot of refined sugar, such as white sugar, the blood glucose level spikes and then rapidly drops. This leads to irritability, nervousness, and fatigue. Consuming too much refined sugar is comparable to injecting it directly into our bodies with a syringe. The brain doesn’t function well when it receives glucose in this manner. A better way to get glucose to the brain is in a “time-released” fashion, which occurs naturally when we consume complex carbohydrates such as whole fruits, legumes, and whole grains.
When I was being trained as a psychologist, the idea that sugar affects mental functioning was ridiculed by a number of my fellow students and even by some of my professors. Years later, when I was in private practice, more than a few of my psychological colleagues also minimized the impact of sugar on the mental and behavioral disorders of their patients. However, this association can no longer be ignored, as increasing evidence testifies.
Sugar and Psychological Disorders
There is evidence that sugar is a culprit in various psychological disorders. In one study, Dr. Malcolm Peet, a British psychiatric researcher, conducted a cross-cultural analysis of the relationship between diet and mental illness. He found a strong link between high sugar consumption and the risk of both depression and schizophrenia.
A typical Western diet high in meat, fats, sugar, and refined foods, but low in fiber disturbs the balance of normal gut bacteria. Some strains of intestinal bacteria manufacture compounds that have positive effects on the nervous system while other species of bacteria produce byproducts which exert detrimental effects on the brain and your mood. This unbalance between friendly and unfriendly gut bacteria can contribute to anxiety and mood disturbances. 1
Sugar and Depression
Other experts state that refined sugar is linked with depression because it does not supply many nutrients and may also deplete B vitamins that are essential for proper nervous system functioning. As previously mentioned, sugar pushes inflammation. Higher levels of inflammation may trigger depression or sustain it.2
The pro-inflammatory states are psychosocial stressors, infection, chronic diseases, poor diet, physical inactivity, obesity, smoking, altered gut permeability, allergies, periodontal disease, sleep deprivation, and vitamin D deficiency.3 Sugar combined with any of these conditions is double trouble.
In my work with depressed individuals, it was not uncommon for many of them to have sugar cravings and consume large amounts of refined sugar. They would often report that this made them “feel” better, at least temporarily. There is a physiological explanation for this—in short, sugar consumption is related to the synthesis of serotonin, which is a mood-regulating neurotransmitter. But, when refined sugar is ingested, the “feel good” effect is only short-lived.
This, in turn, worsens the depressive symptoms. Interestingly, when I worked with individuals who had these sugar cravings, I would encourage them to consume omega-3 and many of them reported that their cravings decreased or eventually stopped.
Sugar and ADHD/ADD
And what is sugar’s role in ADHD/ADD? There is no clear scientific evidence that its consumption can lead to problems with attention, hyperactivity, or any other symptoms of this disorder. Frequent consumption of sugary beverages, however, has been linked to these disorders. 4
However, the observations of many lay persons (and even some health professionals such as myself) reveal that when children consume considerable amounts of refined sugar, they appear to become more hyperactive, distractible, and even aggressive. Thus, even though the empirical evidence is lacking, as a mental health practitioner, I still encourage parents to eliminate refined sugar, in all its forms, from the diets of their children.
Sugar, Performance, and Behavior
Frequent sugar consumption during growth periods of childhood and adolescence may result in pro-inflammatory changes in the brain and increase the risk for social aggressive behavior during adulthood. At least, that is what rat studies indicate. 5
Intake of added sugars is associated with lower cognitive function. 6 The emerging role of dietary fructose in obesity and cognitive decline. Researchers in Malaysia found that excessive sugar consumption among older adults showed a notable association with poor cognitive functions. 7
In her book Potatoes Not Prozac, Dr. Kathleen DesMaisons purports that sugar can be addicting and that this addiction is a measurable physiological state. According to Dr. DesMaisons, sugar acts like a drug, affecting the same receptors of the brain as heroin. There is some scientific evidence that supports the hypothesis that sugar affects the brain as a drug. For example, in one study, rats who binged on a diet of food and sugar water exhibited drug withdrawal symptoms—such as the shakes and teeth chattering—when the researchers stopped this diet or administered an opioid blocker. Sugar consumption, under certain conditions, can become addictive. 8
There is some debate among experts about using the word “addictions” for sugar in the same way as it is used for drugs, alcohol, and other substances. In spite of this controversy, it cannot be denied that many people use foods such as sugar to help them manage uncomfortable emotions, situations, and even thoughts.
Some mental health professionals believe that this may be a form of “self-medication”—the use of self-soothing behaviors, such as the use of alcohol, caffeine, and even sugar—to cope with untreated mental distress. The problem with this type of behavior is that it encourages people to focus on getting relief rather than obtaining true healing for their psychological distress.
The Mind-Body Connection
As we can see, there is adequate support that we can enhance or impair our mental functioning by that which we take into our bodies. As the health authority Ellen White stated, “The relation that exists between the mind and the body is very intimate. When one is affected, the other sympathizes.”
For those suffering from any type of mental or emotional disorder, removing refined sugar from the diet and replacing it with dates, honey, or possibly stevia can contribute to true psychological healing. Why? Because the liberal use of sugar encourages inflammation. Brain inflammation is commonly seen in cases of clinical depression.9 Dates, dried fruits and honey contain health friendly nutrients that can benefit the brain when consumed temperately.
Even if you are not suffering from such difficulties, the avoidance of excess sugar can be helpful for optimal mental and emotional functioning. For those who are accustomed to consuming refined sugar or who may even crave it, the idea of eliminating it from the diet may seem overwhelming. But remember that God will give us the strength we need to properly care for our minds and our bodies. We can say with the apostle Paul, “I can do all things through Christ who strengthens me.” (Phil. 4:13)
- youris.com. “Do microbes control our mood?.” ScienceDaily. ScienceDaily, 20 October 2016.
- Maes M, et al. Depression and sickness behavior are Janus-faced responses to shared inflammatory pathways. BMC Med. 2012 Jun 29;10:66.
- Berk, M., Williams, L.J., Jacka, F.N. et al. So depression is an inflammatory disease, but where does the inflammation come from?. BMC Med 11, 200 (2013). https://doi.org/10.1186/1741-7015-11-200
- Ching-Jung Yu. Sugar-Sweetened Beverage Consumption Is Adversely Associated with Childhood Attention Deficit/Hyperactivity Disorder. Int J Environ Res Public Health. 2016 Jul; 13(7): 678.
- Jung-Yun Choi. Long-term consumption of sugar-sweetened beverage during the growth period promotes social aggression in adult mice with proinflammatory responses in the brain. ((Sci Rep. 2017; 7: 45693.
- Lakan S. Nutr J. 2013; 12: 114.
- Chong CP. Habitual sugar intake and cognitive impairment among multi-ethnic Malaysian older adults. Clin Interv Aging. 2019; 14: 1331–1342.
- Aveno N. Evidence for sugar addiction: Behavioral and neurochemical effects of intermittent, excessive sugar intake. Neurosci Biobehav Rev. 2008; 32(1): 20–39. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2235907/
- Fleger J.Imaging the Role of Inflammation in Mood and Anxiety-related Disorders. Curr Neuropharmacol. 2018 Jun; 16(5): 533–558.