The Link Between Sugar, Your Brain, and Your Mood

A complex relationship exists between sugar, the brain, and mental health. But one thing we know for sure is that sugar can do a number on your emotional well-being.

Does your idea of drowning out your sorrows after a miserable day involve a giant bowl of ice cream or chocolate candy bar? If you answered yes, you are hardly alone.

Some days, a bit of sugar is all it takes to help us forget about our troubles and instantly brighten our mood.

But sugar’s feel-good effects are temporary, and can even make us feel worse than we did before.

Why does this happen, and why do we keep reaching for the sweet stuff when things get tough? More importantly, how might sugar influence our emotional state of mind?

Crave sugar when stressed? Here is why.

Our response to stress is partly controlled by a network within our body made up of the brain and certain hormones called the HPA axis, which describes the interaction between our hypothalamus, pituitary gland, and adrenal glands. This network is activated and causes the secretion of the hormone cortisol during stressful events.

When we eat sugary foods, activity within the HPA axis is weakened and special hormones are released, both of which cause us to feel more relaxed. This then leads us to crave comfort foods even more, perpetuating  a cycle of stress eating.

Eating sugar also stimulates our reward pathway, the area of our brain that controls behavior and memory. This leads to the flow of dopamine, our “feel good” hormone, which elevates our mood and elicits a craving for another hit of sugar.

Is sugar truly addictive?

It appears so. One 2018 study from the British Journal of Sports Medicine suggested that refined sugar may affect the brain in the same way as cocaine.

Scientists observed that animal subjects who ate refined sugar showed signs of craving, bingeing, and building a tolerance to, and experienced reward, pleasure, and withdrawal symptoms, just like those who used cocaine.

The link between sugar, anxiety, and depression

The addictive nature of sugar matters because we now know just how powerfully sugar can affect mood, and the evidence is pretty startling.

A 2017 study showed that among 8,000 participants whose eating habits were followed over 22 years, those who ate more than 67 g of sugar a day were 23% more likely to develop depression compared to those who ate less than 40 g a day. This was seen especially among men,  even when their other health behaviors and diet-related factors were taken into account.

Another recent study found that adolescents who consumed more than 25 g of sugar from soft drinks 7 or more times a week had much higher rates of anxiety and depression than those who did not, and body mass index (BMI) did not seem to be a factor.

4 ways sugar feeds anxiety and depression

Researchers have discovered a few ways our body responds to eating sugar that can lead to emotional distress.

1. Sugar is shown to suppress the production of BDNF, a protein critical for brain health that also acts as a natural antidepressant. Eating too much sugar, especially when combined with lots of fat, damps BDNF activity which makes you more likely to feel depressed.
   
2. Consuming carbs like sugar is believed to increase inflammation within the body, and researchers now believe that inflammation in the brain might be a leading cause of depression.
   
3. Taking in too much sugar can also cause bouts of low blood sugar. The higher your blood sugar levels go, the more insulin is released to quickly carry the sugar out. This can lead to that dreaded "sugar crash," a dramatic drop in blood sugar which may affect mood in a negative way.
   
4. Serotonin is a hormone produced in our brain and other organs that helps us feel happy. Sugar triggers the release of serotonin, giving us an instant lift, but this high does not last long. Serotonin eventually crashes back down, making us feel worse. Serotonin can even become less effective at doing its job in the long run the more sugar we eat.

How to boost your mood with food - the healthy way

There are many delicious ways to lift your spirits without turning to the sweet stuff.

Tryptophan is an essential amino acid we get from certain foods. The production of serotonin depends on how available tryptophan is in our body, so eating tryptophan-rich foods like turkey, nuts, milk, and soy products can help keep your serotonin levels nice and steady.

Phytonutrient-rich foods like fruits and nuts are also linked with less risk for depression. This makes sense, since phytonutrients are known to protect the brain from the impact on stress.

Foods with plenty of omega-3 fatty acids like salmon, sardines, chia seeds, and walnuts work to quell inflammation within the body, an important step toward combating inflammation in the brain that can result in a mood drop.