If you're looking for a quick pick-me-up snack, you might wonder whether to reach for a crunchy apple or pour yourself a cup of coffee. Both apples and coffee give you energy, but in very different ways. Which you choose will depend upon the type of energy you're looking for.
"Energy"
When you hear that a food gives you energy, there are two possible meanings to the word. Some foods give you calories, where a calorie is literally a measure of the amount of energy -- meaning potential to do work -- in a food, explains Dr. Lauralee Sherwood in her book "Human Physiology." Other foods fire up your nervous system and make you feel attentive and energetic, without actually providing your body with cellular fuel.
Apples
Apples contain calories. The three types of calorie-providing molecules in food are proteins, fats and carbohydrates. Apples have small amounts of protein and fat in them and contain plenty of carbohydrates, including both sugar and starch. When you eat an apple, you absorb the nutrient molecules, and your cells can burn them to generate ATP, which stands for adenosine triphosphate. ATP is literally cellular fuel, and your cells use it to do everything they do that requires energy, explain Drs. Reginald Garrett and Charles Grisham in their book "Biochemistry."
Coffee
Unlike apples, coffee contains almost no calories, unless you add calorie-containing extras like milk and sugar. The "energy" you get from a cup of coffee doesn't come in the form of nutrient molecules that your cells burn to make ATP. Instead, coffee stimulates your "fight or flight" nervous system, causing your heart to beat faster and your blood to flow to the peripheral muscles. You also feel more attentive when your "fight or flight" nervous system is stimulated.
Which to Choose
Depending upon what you're looking for in a snack, you might pick an apple, or you might pick coffee. If you haven't eaten enough and are feeling tired because you're low on fuel, the apple will give your cells the fodder they need to continue working. If it's after lunch and you're ready for a nap but have to keep working, however, you might benefit more from the coffee, which will make you feel attentive without increasing your caloric consumption needlessly.
References
- "Human Physiology"; Lauralee Sherwood, Ph.D.; 2004
- "Biochemistry"; Reginald Garrett, Ph.D., et al.; 2007
Member Comments