Avoid bright light later in the day. This is what people ate 20,000 years ago. High carbohydrate diets result in higher insulin, lower blood sugar, and more cravings. Several published studies have shown that athletes perform better and diabetics improve when some of the carbohydrate calories of the average diet are replaced with fat calories. Most people should also reduce total calories.
Carbohydrates temporarily raise serotonin levels, but apparently at a price.
Chromium is important for lowering insulin levels. Excess iron has been implicated in heart disease and other conditions. Heat dramatically lowers serotonin levels because serotonin is used up trying to cool down the body. That's why everyone gets so cranky when they're hot. People with low serotonin levels have trouble sweating and staying cool.