What to eat before exercising

Here's what I had this morning:
1 small banana.
1 small coffee.
1 tablespoon of peanut butter.
1 large glass of water.

Here's why I like to eat this combo before my 40-minute ride into work (where my gym is located).

I feel like the natural sugar in the banana helps to give me a quick burst of energy, while the peanut butter gives me a bit of protein to help keep me going. The coffee is my non-negotiable of the morning (new mom, remember, and slightly sleep-deprived?). And the water is to hydrate myself before working out.

That's what I eat currently. But I thought I'd get an expert's take on what I should eat.

Our Nutrition & You blogger, Joan Salge Blake, is a clinical associate professor and registered dietitian at Boston University in the Nutrition Program. She's also an author.

First, Blake said, you need to eat before you exercise "so that you have enough energy for optimal performance." So don't exercise on an empty stomach!

But, she said, it's equally important to leave enough time before your workout to digest whatever you consume.

"In general, larger meals (making you feel quite full) may take three to four hours to digest, whereas smaller meals (making you feel satisfied but not overly full) may take only two to three hours to digest. If you are having a small snack, you should allow about 30 minutes to one hour for digestion," she said.

She also said that everyone's different, so try experimenting with your eating and exercising schedule.

As for what you should eat, Blake said the consumption of foods "with both protein and carbohydrate before exercise, such as fruit and yogurt, or oatmeal, a few nuts, and skim milk, benefit the body by causing a greater increase in muscle glycogen synthesis than consuming carbohydrate alone." With more glycogen in your muscles, you can increase endurance. Another benefit of consuming both protein and carbohydrate before exercise is that it results in greater protein synthesis after the exercise is over, she said.

What are Blake's top suggestions for the key things to remember when reaching for food before your workout?

1. Allow adequate time for digestion
2. If you eat a large meal, allow 3-4 hours before exercise
3. For smaller meals, allow 2-3 hours
4. Allow a 1/2- to 1 hour to digest a small snack
5. Beware of eating a high-fat meal before exercise because it fat takes longer to digest, and it may cause stomach discomfort and sluggishness.

What do you eat before working out? How much time do you allow for digestion?