Most of us know about the “sugar high” we get after eating sweets. It makes us feel super happy, but then there’s also getting “hangry”—when we’re so hungry that we become grumpy or even angry. This shows that our food affects our mood a lot. Recent studies say that blood sugar changes can be one of the main reasons our diet impacts our emotions. These ups and downs in blood sugar can affect our hormones and nervous system, which sometimes leads to feelings like anxiety and sadness. While many things influence mental health, including social and biological factors, scientists have found that diet plays a huge role, especially in women, in how likely we are to feel anxious or depressed.
As a doctor training in family medicine who also has a Ph.D. in nutrition, I’ve seen how antidepressants can work well for some people but not everyone. This makes me think that mental health treatments should include all possible factors—especially diet. Many studies on food and mental health look at the Mediterranean diet, which has tons of vegetables (especially leafy greens), fruits, olive oil, whole grains, beans, and nuts, with a little fish, meat, and dairy. This diet is thought to improve mood partly because it’s low on the glycemic index, which means it doesn’t cause fast blood sugar spikes. Foods that spike blood sugar fast, like white rice, bread, crackers, and pastries, are linked to a higher risk of depression and sometimes anxiety. Lower glycemic options like parboiled rice and al dente pasta are digested more slowly, making blood sugar rise more gently and reducing depression risk.
One interesting idea on why diet affects mental health is that blood sugar changes mess with our hormones. Every time we eat sugar or carbs (like bread, rice, pasta, or crackers), our blood sugar goes up. This triggers a hormone chain reaction. For instance, dopamine, a hormone that makes us feel good, is responsible for that “sugar high” we get from sweets. Another hormone, insulin, is released to help lower blood sugar by moving glucose into cells for energy. But eating too many sugary foods can lead to a big blood sugar spike, and insulin brings it back down fast. This sudden drop can cause adrenaline and noradrenaline (other hormones) to release. These hormones work to balance blood sugar but can also cause feelings like anxiety, fear, or even aggression. So, what we eat can shape our mood because of how it changes blood sugar and our hormones. It’s surprising that the adrenaline rush from carbs and sugar can hit us four to five hours after a meal; while dopamine gives a quick boost, adrenaline can lead to a slump later.
People’s responses to food vary a lot depending on their sex, genes, level of physical activity, and the types of bacteria in their gut. As I mentioned before, mental health is influenced by many things, and diet alone can’t fix social or psychological factors. But a bad diet can worsen mental health, especially for women, who often respond more strongly to certain foods and the glycemic index. Simply swapping sugar with artificial sweeteners isn’t a solution, as research links sweeteners to depression too. Lowering sugar and carb intake can help stabilize blood sugar, but other approaches work well too.
To improve mood and keep blood sugar steady, try eating low-glycemic carbs like parboiled rice, whole-grain bread, and al dente pasta, and limit high-glycemic foods. I encourage my patients to learn the glycemic index of different foods. Eating carbs earlier in the day (like for breakfast or lunch) can also help prevent big spikes in blood sugar since our hormones are more stable earlier. Also, avoid eating carbs alone; pair them with proteins (like beans, nuts, meat, or fish) or healthy fats (like olive oil and avocado) to slow digestion and prevent big sugar spikes. Another simple trick is to eat your carbs last, after vegetables and proteins, which can significantly reduce blood sugar spikes after a meal.