Here's How What You Eat For Lunch Affects Your Productivity

We usually think of food as fuel.

Just fill up your tank during lunch, then get back to work.

But "Best Place To Work" author Ron Friedman says the analogy is dangerously flawed, since certain foods can cause your productivity to plunge.

"Imagine a world where filling up at Mobil meant avoiding all traffic and using BP meant driving no faster than 20 miles an hour," he writes for the Harvard Business Review. "Would you then be so cavalier about where you purchased your gas?"

What we need, Friedman argues, is to better understand how food powers our brains and shapes our days so we can get the most out of each.

Let's start with the basics.

Pasta and soda give you energy for awhile, but then you crash, he says. Meanwhile, burgers, BLTs, and other fatty meals provide sustained energy but make your digestive system work hard, which makes you groggy.

All of these foods are broken down into the glucose that fuels your brain. When you're low on glucose, your attention drifts and you can't concentrate.

The frightening part: The hungrier you are, the more you'll want to eat French fries or mozzarella sticks, since fatigue leads to bad decisions.

So how can you sidestep that deep-fried feedback loop and choose healthier options that don't cause an energy crisis?

What we need, Friedman says, is to make a system for eating better during the workday and thus avoid the mid-afternoon carb crash.

Here are some suggestions he offered on HBR:

Choose what you're going to eat before you're hungry. Decide on lunch at 10:30, not 12:30. We have better self-control for our future selves than our present selves.

Graze throughout the day. You'll avoid the peaks and valleys that come from burgering at 1 p.m.

Make it easy to eat better snacks. Keep almonds and raisins at your desk instead of M&Ms. Schlep some green bananas to work on Mondays, and eat them as they ripen.

It's in line with the research on willpower. Super successful people don't rely on moment-to-moment intuition to make good decisions; they build constructive routines that take the need to decide away.

That's why President Obama always wears the same suit.