A diet high in processed foods, such as processed meats (bacon, sausage, ham), sugar-sweetened soda and sugary foods (desserts, baked goods) is linked to higher risks of depression, says Palmer. Studies that analyzed adults suffering from major depressive disorder found that those who had a diet higher in processed foods had a smaller hippocampus (the area of the brain that controls memory, mood and learning) than those who had a diet high in nutrient-rich fruits, vegetables and fish.
