Our ancestors got their energy from whole foods like berries, corn, and nuts. In our modern world, our diets are filled with highly refined, highly processed foods. Our food manufacturing capabilities can concentrate, refine, condense, and artificially manufacture more sugar in a single serving than is natural for the body to intake, and our obesity rates reflect this.
In the United States, the average adult consumes 77 grams of sugar per day, which is over 3 times the recommended amount. This adds up to approximately 60 pounds of added sugar per year. The numbers are even worse for children.
This has broad health implications including a higher risk of depression. Research suggests there is a link between sugar consumption and depression.
Sleep disturbances and fatigue are among the symptoms of depression, and inadequate sleep can spur sugar cravings. A 2018 study showed that increasing sleep time led to lower sugar intake the following day.
One study spanning nearly 3 decades examined the dietary habits of more than 10,000 participants, ages 35 to 55. It found that a high-sugar diet played a role in depression and other mental disorders.
A 2009 study found that participants who ate the most whole foods had lower risks of depression than those who ate the least amount of whole foods. In addition, eating more processed foods was linked to a greater chance of depression.
There are several reasons a diet high in added sugars and refined carbohydrates may fuel depression including the following factors:
- poor gut health
- low BDNF (brain derived neurotropic factor)
- Chronic inflammation
- nutritional deficiencies
- unstable blood sugar levels
People who consume a diet high in sugar are more likely to have chronic inflammation, which research has shown is linked to depression. Chronic inflammation is a form of long-term inflammation. This is different from acute inflammation — the redness, pain, and swelling that occurs when you burn yourself, for instance.
You might be unaware that you have chronic inflammation. But your body might think it’s under constant attack, so the immune system keeps fighting indefinitely. This can lead to disease, including depression.
Nutritional deficiencies
Whole foods include all the nutrients needed to digest them. When you consume high levels of processed foods (stripped of their nutrients), the body must pull these vitamins and minerals from other places. Low levels of nutrients, such as vitamin D, folate, B12, omega-3 fatty acids, and several minerals, are linked to depression.
In addition, research published in 2016 shows that a diet of processed foods leads to low energy and more hunger, which spurs overeating and obesity. Also, obesity and depression have strong links to each other.
Unstable blood sugar levels
Whole foods such as fruits and vegetables include fiber, which slows their absorption and keeps blood sugar levels steady. In contrast, processed foods, like candy, sugary drinks, and refined carbohydrates, have a high glycemic index (GI). Your body absorbs them immediately, and your blood sugar levels spike immediately.
A large study looked at the relationship between depression, dietary GI, and other carbohydrate measures in about 70,000 postmenopausal women in the United States. Women previously diagnosed with depression were excluded from the study.
The study found that women who consumed a high-glycemic diet, such as refined grains and added sugars, had greater rates of depression. In contrast, those who ate more fiber, milk products, fruits, and vegetables had a lower risk of depression.
Poor gut health
Healthy gut function is essential to producing hormones and neurotransmitters such as dopamine and serotonin. Diet has a significant effect on gut health, and a diet high in sugar can cause an imbalance in gut bacteria.
Studies show that this microbiome imbalance and gut inflammation may be linked to several mental illnesses, including depression and anxiety.
Low BDNF
BDNF (brain-derived neurotrophic factor) is a protein that plays a role in the growth and maintenance of brain cells.
Research shows that a high-sugar diet reduces the production of this protein and that low BDNF is often seen in people with depression. Antidepressants help regulate the expression of BDNF both in the short and long term.
What About Artificial Sweeteners?
In an effort to avoid sugar, some people opt for alternative sweeteners, such as aspartame, an artificial sweetener commonly used in diet sodas. However, research from 2017 shows that aspartame is linked to behavioral and cognitive problems. Some of these symptoms include:
- learning problems
- headaches
- seizures
- irritability
- depression
- insomnia
Splenda (sucralose) is another commonly used alternative sweetener. Research shows Splenda is linked to poor gut health and inflammation, which are linked to depression. Stevia, a natural sweetener without calories, is derived from the leaves of a plant in the chrysanthemum family. Research on Stevia has been mixed. While it may help you lose weight and lower cholesterol, some 2020 research suggests it may disrupt communications between different bacteria in the gut microbiome.
Reducing your sugar consumption
You may opt to stick to fresh or (unsweetened) dried whole fruit for your daily sweets when managing depression, including high-pectin fruits, such as:
- apples
- blackcurrants
- gooseberries
- oranges
- plums
Other fiber-rich fruits in their natural form include:
- bananas
- kiwi
- mangoes
- raspberries
- strawberries
Eliminate processed sweets from your diet and use these other strategies to curb sugar consumption:
- eating whole foods
- consuming more healthy fats, such as olive oil and avocados
- replacing refined carbs with whole grains
- getting enough sleep, as a lack of sleep can cause sugar cravings
Final thoughts
The dopamine surge from a sugar rush can lift your mood temporarily, so it can be tempting to keep a diet chock-full of simple or artificial sweet ingredients. But for the long-term management of depression, you may want to make changes to your diet where possible to increase your energy and support your mood. Favoring whole foods with naturally occurring ingredients, complex carbs, and omega-rich options can be the most healthful.