Just like any other organ in your body, your brain – including your thoughts, emotions, and memories – is heavily influenced by lifestyle choices. Neurotransmitters are chemical messengers in the brain that help to carry a signal across a synapse. They include chemicals such as norepinephrine, serotonin, and dopamine, and can affect everything from mood to cognition. When your blood sugar goes haywire, so too can your neurotransmitters. And this can bring about major changes in brain function.

You can fall victim to a variety of mood disorders if your body doesn't manufacture neurotransmitters in the right quantity. Insufficient dopamine, for example, can destroy your ability to feel pleasure. Your blood sugar levels affect your body's ability to make neurotransmitters. Conditions such as insulin resistance and hypoglycemia can both play a role, so changes in your mood might not just be in your head; they could signal illness.

Neurotransmitter problems don't just occur when your body doesn't make the right quantity of neurotransmitters. Each chemical messenger has to interact with other neurotransmitters, and your blood sugar can affect the way these interactions unfold. For example, serotonin – which helps regulate your mood – depends on protein consumption. In industrialized countries, few people struggle to get enough protein, but this doesn't mean you're home free.

Your body has to convert tryptophan into serotonin to properly regulate your mood, which is why many holistic practitioners recommend supplementing the diet with tryptophan. But if your blood sugar levels aren't properly balanced, your body can't effectively turn tryptophan into serotonin, which means no matter how much protein you consume, your neurotransmitters can be left unbalanced. High-sugar foods such as sweetened drinks and the refined sugars in pasta and other snacks can cause your blood sugar to skyrocket, altering your mood.

If you've ever felt exhausted after eating a large meal, the interaction of neurotransmitters and sugar could be to blame. After you eat a sweet meal, you may feel elated as your body's serotonin level rises. But to eliminate excess sugar, your body has to convert glucose into fat. This energy-draining process can leave you feeling exhausted. When your body's cells are insulin-resistant, your cells won't get enough glucose for energy production, further compounding your exhaustion. Overeating, chronic stress, and insufficient exercise can further compound the problem.