There's no denying that sugar packs a wallop on your body. The sweet temptress is addicting in all its forms, stroking your brain's reward centers and overwhelming your body with bursts of energy.

But if you didn't already know, excess sugar can hammer your health. Fructose found in sugary drinks like soda might damage your brain; people who often guzzle sugary beverages are more apt to have a crappy memory and a significantly smaller hippocampus, which is vital for learning, according to new research from the Framingham Heart Study.

Before we start delving into even more reasons why a fit guy might want to remove the sweet stuff from his diet, let’s clarify some murky areas.

First things first: What is sugar?

You'd be surprised how many people simply don't know this.

“Sugar is a simple carbohydrate that provides energy for your body to use,” says Jordan Mazur, M.S., R.D., the coordinator of nutrition and team sports dietitian for the San Francisco 49ers. For endurance athletes—marathoners, triathletes, and cyclists—sugar is something of a holy grail, providing quick-hit fuel when they start to fade. Your brain also depends on glucose, one of the main forms of simple sugar (the others being fructose and galactose) to power other functions in your body. But nutritionally? “Sugar has no other value,” Mazur explains.

It's also important to note that you don't have to consume straight-up sugar to get glucose. Your body can derive simple sugars (aka monosaccharides) from more complex carbohydrates, which your body needs time to break down, and therefore provide sustained energy.

We don’t mean to vilify simple sugar, though. There’s a big—huge—difference between natural sugar and the factory-made stuff like sugar alcohols, artificial sweeteners, or other processed gunk. Here's everything you need to know about glucose, fructose, and galactose, which are the three most basic forms of sugar.

The difference between "natural sugar" and "added sugar"

“Naturally occurring sugar is what’s found in whole, unprocessed foods, such as milk, fruit, vegetables, and some grains,” Mazur says. “One of the most common natural sugars is fructose, found in fruit, and lactose, found in milk.” These sugars aren’t necessarily bad, but they are sugar.

Added sugar is what's dumped into processed foods and drinks as they’re being made. “Food manufacturers may add both natural sugars (like fructose) and processed sugars (such as high-fructose corn syrup) to processed foods and drinks,” like bottled juices and packaged snacks, he adds. Likewise, any type of sugar you add to your food at home—brown sugar, agave—is also an added sugar, even if it's inherently a natural sugar.

In general, natural sugars can be good for you when consumed in moderation and at the right time of day. “For example, athletes who consume sugar before intense exercise and after exercise can put the fuel back in their tank for the next time they work out,” Mazur says.

Be aware, too, that added sugar can go by lots of different names on nutrition labels—so even natural sugars can be added sugars in certain contexts.

Should you slowly ease sugar out or cut it out completely?

It's tempting to drop sugar altogether, but it's probably not the best approach. “Going cold turkey can leave your body in a state of shock, especially your brain, which uses carbohydrates, or sugar, as its main fuel source,” Mazur says. Remember: Sugar and carbs are still your main fuel sources for high-intensity workouts.

Some people choose to follow a sugar- and carb-free keto diet, which forces the body to burn fat for energy, a process called ketosis. The keto diet can require weeks of acclimatization. It can be helpful for people trying to lose weight, but presents challenges to athletes in non-ultra-endurance sports.

Otherwise, you'll want to keep some sugar in your diet. Carbs are your brain’s primary fuel, per research published in Trends Neurosci. In fact, while your brain only accounts for about 2% of your body weight, it consumes approximately 20% of glucose-based energy. Try to consume sugar when you’re most active, because your body will use it for fuel (pre- and post-workout, when it’ll be eliminated, and not converted to or stored as fat), Mazur says. 

5 ways to ease sugar out of your diet

  1. Try zero-calorie sweeteners, like Splenda, in moderation, Mazur suggests. While the science has gone back and forth about whether artificial sweeteners are better for you, it comes down to preference. If you want to cut sugar as a means of cutting calories, this can help.
  2. "Buy fresh fruits or fruits canned in water or natural juice," Mazur says. Anything canned in syrup, especially heavy syrup, is a no-go.
  3. This is a really easy fix: "Instead of adding sugar to cereal or oatmeal, add fresh fruit. Try bananas, cherries, or strawberries," Mazur says.
  4. "Enhance foods with spices, like ginger, allspice, cinnamon, or nutmeg instead of sugar," he adds. Spices pack tons of flavor, but without the calories.
  5. Take white and brown sugar out of your kitchen, or throw them away altogether, Mazur says. Your taste buds will adapt to coffee and tea without added sugar, and slowly you'll stop craving it. Put an emphasis on vegetables, whole grains, and lean proteins that can fill you up and kill cravings. You want low-sugar foods readily available and in-sight. Also, educate yourself. Some of the most commonly eaten foods are latent sugar bombs. Take a look at this list of surprisingly sugar-rich eats

Foods and drinks that can be deceptively high in sugar:

  • Whole-grain cereals and granola
  • Flavored instant oatmeal
  • Frozen foods
  • Granola bars, protein bars, and nutrition bars
  • Pasta sauce
  • Smoothies and fruit juices
  • Yogurts
  • Barbecue sauce, ketchup, salad dressing, and other condiments

Here's how most of these popular foods compare, sugar-wise, to a powdered donut