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4 Surprising Ways Your Diet Is Affecting Your Productivity

When, what and how you eat can have some eye-opening effects on your ability to get things done — and get ahead — at work.
What you eat can have surprising effects on your ability to work.
What you eat can have surprising effects on your ability to work.

You know that your diet has a profound effect on your weight, your sense of wellbeing and even your risk factors for certain illnesses, but did you know that it also has an effect on your productivity?

You might feel a surge of productivity after lunch, or feel especially useless on mornings when you skip breakfast, but when, what and how you eat can all have some surprising effects on your ability to work.

1. Caffeine: The Double-Edged Sword

There’s a reason nearly two-thirds of Americans drink coffee every day, with an average of 2.7 cups per day, per drinker. Coffee is one of America’s favorite caffeinated beverages, meant to serve as a pick-me-up before or during work.

Image: Steaming Cup of Coffee
Steam rising from coffeeJohn Brecher / for NBC News

Instinctively, you might guess that caffeine has a positive effect on your productivity, since it’s associated with higher energy levels, reduced fatigue and better alertness and focus. And for the most part, you’re right. A cup of coffee has about 200 milligrams of caffeine, which is enough to suppress the adenosine in your brain that would ordinarily make you feel sleepy, and provide you with cognitive boosters like better memory and cognitive function. If timed right, coffee (and other forms of caffeine) can improve your performance in the short term.

Create a budget for your caffeine consumption, so you don’t overindulge and interfere with your sleep cycle. Consider gradually shifting to decaf coffee as the day moves toward a close.

However, much depends on how you consume caffeine, and in what quantities you consume it. Consuming too much caffeine can lead to jitteriness and anxiety, distracting you from work and interfering with your sleep schedule; and if you lose too much sleep, no amount of caffeine will be able to make up for your cognitive impairment. At the same time, caffeine dependency can actually cause withdrawal symptoms if you’re ever left without coffee for a day.

2. Low Blood Sugar Can Wreck Performance

Experts suggest keeping fruit or nuts around as a snack to boost your energy midday, and that’s generally good advice, but it pays to know why. Blood glucose is a complicated topic, and its effects on productivity aren’t cut-and-dry.

Researchers have found that the ideal amount of blood glucose to have circulating in your body is 25 grams; less than that, and your productivity will take a hit. Any more than that, and you won’t be able to do much with the extra energy.

So how does this matter to your diet? Almost anything you eat will raise your blood sugar in some way; therefore, if your blood sugar gets too low, you’ll need to eat something if you want to achieve your optimal performance.

However, not all things raise blood glucose in the same way or in the same amounts; foods higher in the glycemic index, like candy bars and white rice, will cause your blood glucose to spike, preceding a crash shortly thereafter. Low glycemic index foods, like oatmeal and most fruits and vegetables, will provide a steady release over the course of hours.

3. Hunger Can Kill Productivity and Make You 'Hangry'

Have you ever felt less productive and more irritable because you were hungry? You aren’t alone. It turns out, judges give harsher sentences when they’re hungry, and people are generally less productive when they have food on the mind. This is linked to blood glucose, but serves independently because of the subjective feeling of hunger. Eating filling foods, like proteins and foods high in fiber, early in the day will help you stave off hunger—and feel a lot less grumpy. Having a healthy snack nearby can also help.

4. Obesity Causes Productivity Loss

The foods you eat have an impact on your health, but your health has an impact on your productivity. When it comes to absenteeism (days missed due to health complications) and presenteeism (productivity lost during the day due to health complications), the annual cost for a normal-weight employee is $10,000.


The annual cost for an obese employee is $16,000. Put simply, engaging in unhealthy eating habits could cause health-related productivity losses 60 percent more than those of average employees.

How to Fuel Your Workday

So what can we learn from these four insights? Follow these fast tips to get the most out of your workday:

  • Keep healthy choices available. It shouldn’t surprise you that healthy foods like fruits, vegetables and lean meats are significantly better choices than fast food or vending machine fodder. Having these foods nearby as a potential snack can keep you making healthy choices (and keep your blood glucose regulated throughout the day).
  • Don't skip breakfast. Start your day off right with a substantial meal, full of proteins and complex carbohydrates. Eggs and whole wheat toast are a solid bet.
  • Graze. Don’t save up for lunch and stuff your face. It’s better to graze, steadily throughout the day, to keep your blood glucose levels even—again, as long as you’re indulging in healthy options with a low glycemic index (GI).
  • Have a caffeine "budget." Caffeine is good for your productivity, but only when consumed in moderation. Create a budget for your caffeine consumption, so you don’t overindulge and interfere with your sleep cycle. Consider gradually shifting to decaf coffee as the day moves toward a close.
  • Get some exercise in, too. Though not directly related to your diet, consider getting some exercise in before or during the day. As little as 20 minutes of exercise can give you a short-term cognitive boost and reduce your fatigue. Plus, the exercise will keep you in better shape, so you won’t suffer from the productivity loss associated with obesity over the long term.

You don’t have to become a health nut to reap major benefits. A handful of simple changes to what, when and how you eat and drink each day will do the trick!