Advise on Eating While Interviewing

When you're interviewing, you want to be alert and responsive, and you want to give off the best impression you can; one wrong answer and your prospects of getting the job are over. Also, you want to appear interested in what the people you meet with have to say, not someone who can't keep the eyelids from closing. Therefore, aside from sleeping very well the night before, I recommend that you eat and drink very lightly and carefully:

• Don't be tempted to eat a lot of stuff at each meal. Avoid heavy foods like beef because your body needs more energy to digest such foods, and when your stomach needs that energy, you will feel tired.
• Avoid certain foods that will increase your body's production of Serotonin and Melatonin, because they will naturally make you sleepy. For example, lunch-time pasta is one well known example of a terrible interview-time food to have. It'd make you sleepy for the rest of afternoon, which is particularly bad because it is coupled with your body's natural "siesta-time" tendency to slow down in the afternoon.
• Avoid spicy foods, very oily foods, or anything that will upset your stomach (not to mention stuff that will make you bloated), cause you to sweat (body odors), or foul your breath. If after a meal you still have to meet more people, it's not a bad idea to stop by the bathroom to brush your teeth and rinse with a mouthwash (on a job interview, a piece of food sticking out between your teeth will not be as funny as when it happened to George Costanza.)
• Avoid too much sugars, and especially too much soft drinks: after the initial "high" you get from the sugars, you'll crash and burn.
• If the interviewing process is lengthy (say, spanning several months and lots of interviews), you should avoid eating too much in the first place (yes, even if it's free food). You don't want to find out that you've gained a lot of weight in a short period of time, and that you no longer fit into your interview clothes.
• Avoid alcohol at all costs (unless it appears needed for "social" reasons, but even then, you don't have to finish your glass of wine and ask the waiter to leave the rest of the bottle on the table).
• Avoid messy foods with lots of colorful sauce that could drip (e.g., pizza, spaghetti, etc.). Getting a red stain on your brand-new white shirt is hard to recover from. Besides, who wants to hire a sloppy computer scientist or programmer who can't even keep food off their clothing?
• Don't try new or exotic things while on the road. Stick to food you've had before that agrees with you. An interview is the wrong time to discover that you're allergic to, say, east Samoan sea urchins.
• You'll be going with people to meals (breakfasts, lunches, dinners, and other hosted events). These events appear more relaxed and social, but don't be fooled! You will be evaluated just as much during such meals as during your talk. So don't get too comfortable because of the apparent relaxed environment: don't say things that could hurt you any more than you would during a one-on-one interview or your talk. Be courteous, polite, and engaging: listen and answer carefully, ask questions as needed, don't interrupt others in mid-sentence, and don't speak with your mouth full.
• The choice of food you order may speak volumes about your personality. If everyone ordered a simple salad and you've ordered an unusual meal (say, that east Samoan Sea urchin), people may get the impression that you're an odd person; no one wants to hire someone who has a "difficult" personality. If, on the other hand, you say "I'll just have what everyone else is having," then you might be dubbed a follower, not a leader. Remember that as a future employee (especially if going into research or academia), you have to demonstrate that you're an independent thinker, but also that you will follow others as needed. Striking this careful balance is important.
• As much as possible, stick to vegetables, simple salads, fish (or chicken breast if you don't like fish), and soups: things that will be easy on your body.
• Drink plenty enough of plain, good 'ol water. That should keep your body hydrated and well lubricated. (One unfortunate side effect is going to be that you'll be visiting the bathroom frequently.)