Often we're told what not to eat, but it's also important to know what we should eat. Not all foods have the same impact on your body. When it comes to special occasions — weddings, job interviews — what foods keep us in the perfect state? Find out.

BUSINESS PRESENTATION OR JOB INTERVIEW

Objective: To look calm, composed and focused, prepared and knowledgeable. Don't show up for either event hungry.

Best foods: Take 3 to 4 ounces of lean protein such as fish, chicken, low-fat cottage cheese or an egg-white omelet and add one slice of whole-grain bread or brown rice and l cup of fruit or vegetables. If you normally drink coffee or other caffeinated beverages with your meal, continue to do so, says Judith Wurtman, a research scientist at MIT and co-author of "The Serotonin Power Diet" (Rodale, 2007). Drink water too.

Why? Eating protein helps make sure the brain is manufacturing the chemicals (i.e., norepinephrine and dopamine) that control mental alertness. And, according to Wurtman, "The carbohydrate, fruit or vegetables are included to nourish you and make sure your body is getting enough calories and nutrients." The caffeinated beverage helps to keep you alert.

Feeding time: At least an hour before the presentation, to make sure that it is at least partially digested and its effects on your brain are working.

How much should I eat? A moderate amount. Stay away from bulky vegetables so you don't feel uncomfortable.

Avoid: High-fat foods such as butter, mayonnaise, cheese and cream — They will make you feel muddleheaded.

ROMANTIC DINNER

Objective: To be calm and feeling good, debonair, funny, sexy and not too hungry.

Best foods: Eat a light meal such as a small chicken sandwich or scrambled eggs and toast beforehand. For dinner, order foods that are easy to eat and don't require much attention. Fish (without bones) is a good choice because you don't have to fuss with cutting tough meat or spending a lot of time chewing. You should be talking instead. Pasta's too messy. Same with salads. Nibble on bread before the meal is served. Be careful with alcohol.

Why? Eating ahead of time lets you focus on your dinner partner and not on your hunger. Eating carbs before the meal is served calms you down, says Wurtman.

Feeding time: Eat your at-home meal about two hours before the date. If you don't get to finish your meal at the restaurant because you're so busy talking, don't worry: You can have a big breakfast.

How much should I eat? At the restaurant, eat about half of what is served.

Avoid: High-fat foods such as three-cheese pizza or nachos — they tend to induce sluggishness.

WEDDING DAY

Objective: If you're the bride, you probably spent the past six months working to fit into that expensive, one-time-only dress. Ideally, you need meals to help you feel calm and collected.

Best foods: Wurtman suggests eating a substantial breakfast, such as scrambled eggs, toast and juice, or yogurt and cereal, or fresh fruit, yogurt and a low-fat muffin. Then, while you're getting ready, eat foods that are easily digested and bland: a banana or melon, plain crackers, cereal and milk, a nibble of plain chicken and maybe a roll.

Why? Breakfast may be the only meal you get to sit down and eat. Once you start getting ready for the wedding, eat small snacks so you don't feel bloated.

Feeding time: "Try to fit in your snacks during the preparation time, when your hair and makeup are being done," says Wurtman. Then have someone bring you something to eat after the ceremony during picture-taking. If you're too busy to eat, have juice to get a few calories.

How much should I eat? Only what feels comfortable.

Avoid: Alcohol on an empty stomach; it may make it harder to control your emotions.

Charles Stuart Platkin is a nutrition and public-health advocate, and author of "Breaking the FAT Pattern" (Plume, 2006). Sign up for the free Diet Detective newsletter at www.dietdetective.com.