If you want energy and to stay awake, eat more meat, fish or poultry than carbohydrates at breakfast and lunch. If you want to fall asleep, eat more carbohydrates at dinner. Also, don’t eat too much food at one time as that can also make you sleepy (for instance > 500 calories at a meal). Blood pools in your stomach / intestinal area after eating so that your body can pick up the calories and nutrients from the food you ate. Perhaps if you eat smaller meals, you would feel more energetic and awake.
Exercise is great to wake a person up. Is there someplace at work where you could walk for 15 – 30 minutes during the day like climbing stairs or walking outside? You don’t need to break a sweat, just get up and move.
Thiamine, riboflavin, and niacin are necessary vitamins to convert food into the energy fuel your body runs on. Read my topics on these nutrients for more info. If you don’t eat a variety of foods like meat, starches, vegetables, fruits, and dairy, then perhaps a one a day vitamin with 100% of the RDA for all vitamins and minerals might make sense. As a male, make sure you are not taking iron supplements though as a high blood hemoglobin has been associated with an increased risk of heart attacks in adult men.