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The Truth About Sugar for Runners

Sport Nutrition

As a runner, you might be a little bit confused about the role of sugar in your diet.

Is it bad for you? Won’t it slow you down or make you gain weight, or develop diabetes?

Or, is it essential for running performance? Don’t we need it for energy to fuel our runs?

These completely opposite perspectives might leave you questioning whether you should be eating sugar or avoiding it. 

Let’s take a look at this debate and find out the truth about sugar for runners. 


Let’s start with the bad news…

It’s pretty safe to say in North America we eat too much added sugar.

But what are added sugars exactly?

These are the sugars that are added to foods during processing (pop, slurpees, sweet cereals, desserts, muffins), or by us during cooking/food prep (such as adding sugar, honey or syrup to our coffee). It’s important to make the distinction that these do not include sugars that naturally occur in fruits, vegetables, milk, or grains and starches.

Remember though that whether we get our sugar from natural or added sources, it is all digested and metabolized the same way. The real difference is that added sugars are often found in foods that have little to no other nutrition- such as a can of pop or a frappucchino.

How much sugar are we eating?

The Canadian Community Health Survey in 2004 found that on average, we’re consuming about 26 tsp of added sugars per day. Teen boys had the highest level of consumption at 41 tsp per day. To put it in perspective, that’s about 4 cans of coke per day.

It’s important to note that this is self-reported data (meaning the subjects answered a survey about their dietary habits), and that the data is represented as an average. 

This is something to consider because we do tend to fudge things a bit when it comes to self-reported dietary intake; (we might “forget” about little extra treats here and there, or underestimate how much sugar goes into our morning coffee). 

These values are also an average, meaning some people are taking in MORE than 26 tsp per day. 

Each tsp of sugar provides us with 16 calories. This may not seem like a large number, but if you add up that 26 tsp average, it’s over 400 calories per day that the average person is consuming that has little other nutritional value.

So, that’s the story with sugar for a ‘typical’ population. But, what about sugar for runners?

Curious about carbohydrates and running? Click here to find out more

So, what’s good about sugar?

Sugar (or carbohydrates) is actually our body’s primary fuel source. We can think of them as either quick to digest or slow to digest, and BOTH are essential to athletic performance.

Slow-digesting carbs (or complex sugars) like whole grains and starchy vegetables help to keep us full and satisfied. They also provide us with essential nutrients like fibre, protein, vitamins and minerals.

On the other hand, fast-digesting carbs (or simple sugars) provide us with quick energy, which is especially important before or during a workout! Examples of these can be sports drinks and gels or juice. And some (like fruit!) can also provide us with key nutrients!

How much sugar should we be eating?

The maximum added sugars per day recommended by the American Heart Association for women is 6tsp, which equals 24 grams, or 96 calories. 

For men (who it is assumed should eat more calories than women therefore can accommodate more added sugars in their diets) the limit is 9tsp per day, or 36 grams, which equals 144 calories.

To put this into perspective, let’s take a look at a can of pop. The nutrition facts on a can of pop is listed at 150 calories. There is zero protein and zero fat, which means that 100% of the calories are from sugar. 150 calories divided by 4 calories per gram gives us 37.5 grams of added sugars, which is equal to 9.3 tsp. This is more than the daily upper limit for both men AND women.

Do these guidelines also apply to runners?

For runners, carbohydrates should contribute to most of our daily calories and are the foundation of a runner’s diet! 

In terms of added sugars, runners generally don’t need any more than the average person on a day-to-day basis. However, there are times when additional sugar can benefit a runner.

Before or during a long or intense training period, you most likely need some sort of readily available energy source to help fuel your workout. Simple carbs like juice or gels are a great example that provide quick energy.

After a high-intensity training session, easily absorbed carbohydrates are a great way to replenish glycogen stores.

But make sure you don’t rely on sugar as your only source of energy!

Research has shown that runners can actually become more fatigued when consuming only high glycemic index foods like white bread or fruit.

Consuming simple carbohydrates along with some protein and maybe a little fat can keep you fueled up for longer! For example this could look like a piece of toast or fruit with some nut butter in the hours before a run.

Just watch out for foods that contain lots of fibre when training. These take much longer to digest and eating these before a run might trigger an upset stomach or some gut problems while training. To read more about gut issues and running, click here!

Does sugar make us gain weight?

Yes and no. Sugar can lead to weight gain due to excessive calories being consumed. The same would apply to an over-consumption of calories from fat, protein, starches, or alcohol. 

Weight gain and loss can be a complex issue, but at the end of the day if we are eating more calories than our body can use for energy, we will wind up gaining weight.

Given that a single can of pop contains more than a typical person’s limit for added sugars in a day, it is arguably easier to eat too much sugar than it is to eat too much fat or protein. 

Sugar on it’s own does not give us the same satiety signals that high protein, high fat, or high fibre foods do, particularly when it comes in liquid form in beverages.

Sugar is rapidly digested and absorbed in our gastrointestinal tract (the gut). Protein and fat tend to be more “filling” and take a longer time to be broken down by our bodies. This is why simple sugars are so great for fuel during a run, but not so great for keeping us full after a meal.


So what’s the truth about sugar?

The bottom line – sugar isn’t ‘bad’ for you. In fact, it is essential to perform your best as a runner!

We know though that there are different types of sugars – some that are slow-digesting (like whole grains and starchy vegetables) and others that are fast (like fruit, juice and gels).

And for a runner, there’s a time and place for each of them!


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