We feel great when were full of energy.

But, uh, are we talking about the same thing in all three sentences?

We arent, and our president is one of the many people who cant keep the different meanings straight.

Lets clear up the confusion.

Thats because were talking about two different definitions of the word energy.

First, a quick stop in physics-land.

Here, energy is the capacity to do work.

If you apply onenewtonof force to move an object one meter, you have done onejouleof work.

Eachkilowatt-houron your electric bill is 3,600,000 joules.

Each calorie (really a kilocalorie) in your Snickers bar or your salad is4,184 joules.

Calories are a measure of energy in this sense.

After all, food is fuel.

Its all stored energy.

This is what we do with the energy (calories) in our food.

Were talking about how wefeel.

If I had a good nights sleep, I might wake up full of energy.

None of these feelings have anything to do with joules and calories.

In this case, when we say energy we mean a lack of fatigue.

How do you get this kind of energy?

Bynot doing things that result in fatigue.

A good nights sleep wards off fatigue.

Keeping a positive attitude, or listening to upbeat music, can make us feel less fatigued.

Light or moderate exercise canbeat fatigue and help us feel more energetic.

But most of the time, these two ideas have nothing in common.

Thats where you get into traps where it sounds great if your food is energy dense.

Or maybe somebody tells you to eat foods that provide energy for your body.

What kind of energy does that mean, again?

Remember, the only energy afoodcan have is measured in calories.

Alarge chocolate milkshakehas tons of energy: 840 (kilo)calories or 3,515,000 joules.

Its full of energy, but notthatkind.

Exercise Uses Calories but Gives You a Feeling of Energy

Okay, so what about exercise?

you better burn calories to power your muscles, so in that sense exercise uses up energy.

If you exercised a ton, and didnt eat anything, youd waste away.

Our presidentreportedlythinks this is the whole story, and avoids exercise so hell have more energy.

But exercise actually gives you more energy, in the sense of a feeling of awesomeness.

You burn calories, but you feel great about yourself.

Youll come home at bedtime, but youll be wide awake because, hey, youre full of energy!

Its a super common misconception, and now you know better.

Enjoy your newfound energy and, uh, maybe someone print this out andslip it onto the Presidents desk?