Why Athletes Need Sugar and Carbs in Their Diet

Do you have a sense that avoiding carbs is eating “clean?” Do you figure that anything with bread or flour in it is junk food? Is sugar something to be avoided at all costs? If so, we need to have an intervention. Carbs—including sugar—are good, actually. And avoiding them can do more harm than good when it comes to health and fitness.

To find out how much carbohydrate you’re actually getting, any nutrition app (like Cronometer, which is free) can keep track of how many grams of carbs you get throughout the day. If you use an AI-based tool, like the chatbots built into many wearable apps these days, make sure to double-check against the food’s actual label to be sure it’s tracking the grams of carbs correctly.

Don’t confuse low-carb diets with healthy eating

As I’ve often said, the things we do to lose weight are not the same as things that make us healthier. You can lose weight on a low-carb diet, and that’s fine. But that doesn’t mean that avoiding carbs is going to make you healthier in general.

And in fact, a lot of the downsides of dieting can be improved by allowing yourself more carbs. The fact that low-carb and higher-carb diets can both work for weight loss does not mean that they are equivalent in every way. People who eat more carbs tend to have less fatigue during exercise and get to be more flexible in their diet, whether they are trying to lose weight or not.

Carbs include sugar, starch, and fiber

Before we get deeper into this subject, let’s talk about what carbs are. Pretty much everything we eat can be categorized as a fat (including oil), a protein, or a carbohydrate. Carbohydrates, or carbs, include: 

• Sugars, including table sugar, glucose, and fructose. There are naturally occurring sugars in fruits, vegetables, and milk.

• Starches, which plants use as a form of carbohydrate storage. White bread and white rice are examples of foods that contain a lot of starch without much else.

• Fiber, which our bodies can’t completely digest. Different types of fibers are found in whole grains, fruits, vegetables, and beans.

You may hear about “complex” carbs. To a biochemist, starches and fiber are both complex carbs. But the term has been misused to mean “foods with fiber in them,” like fruits and whole grains. White bread is full of complex carbs, so don’t take this distinction too literally. 

What’s important to remember is that sugars and starches can both be broken down to create energy for our body fairly quickly. Fiber slows down this process, but so do fats and protein. So if you need fast energy when you’re in the middle of a run, you may prefer sugars or starches. If you want a full meal that you can digest over time, giving you all its various healthy benefits, foods with fiber, protein, and fats will be good for you—but these meals can include sugars and starches in the mix as well.

Sugar isn’t poison or toxic

It’s not great to get a lot of added sugar in your diet; that much is true. And most Americans do get a lot of added sugar in our diet, far more than our bodies can put to good use. I’m not endorsing that excess. (Most of us would probably be better off if we cut out at least some of that sugar.)

But I am saying that we need to pay attention to why too much sugar is bad, and not overreact by demonizing sugar or saying it’s poison, it’s toxic, and that it needs to be eliminated. There’s absolutely no reason to believe those myths. Too much sugar is bad for us because sugar is a dense source of “empty” calories. But our bodies can deal with a moderate amount of sugar just fine. 

And if you’re an athlete—even a recreational one, somebody who likes to jog and lift—you may find that simple carbs like sugar help to fuel your workouts. That, in turn, lets you do more quality exercise. Take marathoners as an example: sucking down packet after packet of sugary gels is not natural or normal; but neither is running 26.2 miles at a steady pace without stopping. The one fuels the other. Even if you want to make an argument about what humans evolved to do, you’ll need to come to terms with the fact that hunter-gatherers eat a lot of honey. 

Carbs can reduce fatigue before and during workouts (and maybe also in your daily life)

If you’ve ever felt pooped during a long workout, you might chalk that up to the workout itself. But people who are either dieting or who are choosing to eat “clean” may feel this way because they’re short on carbs. 

I say this based partly on research that has shown fueling to make a huge difference for endurance athletes, as in my example above about marathoners. That much is scientifically established. 

The other part is a mostly anecdotal, but strongly supported-by-anecdote observation, that people who eat carbs before their workout tend to feel more energetic in those workouts. It’s why the best stim-free preworkout, if you want to avoid caffeine, is called eating a damn snack. If you’ve been doing fasted cardio, or you’ve been eating keto all day long and then trying to grit your teeth through a workout when you’re exhausted, try having some carbs before your workout. You’ll feel a world of difference.

And it’s not just physical performance. Research also shows that eating a low-carb diet can interfere with cognitive tasks like memory and attention. Your body can get by on a low-carb diet, but it performs best when it has carbs available.

Eating carbs allows more flexibility in your diet

A big part of the reason low-carb diets are effective for weight loss is that it’s hard to avoid carbs when you’re eating out, or grabbing a quick snack on the road. Most processed food products include carbs, but so do most home-cooked meals, unless you’re specifically preparing them without carbs. 

As a result, you don’t have much to eat when you’re following a strict low-carb diet, and that’s a big part of why it becomes so easy to limit your calories. But notice that if you’ve cut out carbs, you’ll end up avoiding a lot of healthy foods, including fruits, vegetables, and whole grains, which have plenty of vitamins and other nutrients that need to be present in a healthy diet. It’s real hard to eat fiber if you’re swearing off starches and sugars as well. 

More carbs means you don’t need as much protein

It’s important to get enough protein, and I don’t just mean hitting the bare minimum of the RDA. If you work out, you’ll want more protein, and if you’re trying to lose weight, you’ll want even more protein, to name a few common reasons why it’s good to work protein into your diet.

Carbohydrates actually help you with this job. Carbs are understood to be “protein-sparing,” meaning that if you get plenty of carbs in your diet, your body is less interested in breaking protein down to burn it for energy. Or to put it another way: on a low-carb diet, some of the protein you eat goes to waste, just because your body needs some kind of fuel for energy, and it doesn’t have its preferred source, carbs. So if you have a hard time getting enough protein in your diet, making sure that you have plenty of carbs will help the protein you do get to go farther.