Hydration & Exercise, Part 2: Utilizing the Nutrition Label to Meet Hydration Needs

If you remember from the last blog, Hydration and Exercise, we talked about the importance of proper hydration during exercise and benefits of including electrolytes as part of a hydration routine. In this follow up, we will be discussing how to utilize the food label to make sure your hydration needs are being met.

We talked about how water is good for meeting hydration needs. However, sports drinks offer additional benefits, such as carbohydrates, sodium, and flavor. These are important because they can improve performance by optimizing water absorption and fluid intake. Carbohydrates are an important macronutrient needed to supply the body with energy, while sodium assists in absorption of fluid. A flavor that is pleasing to the palette, encourages someone to drink more. After all, who wants to eat or drink something that tastes bad?

But how do you find the right beverage? Read on to learn about utilizing the food nutrition facts label to meet your needs.

How to read the nutrition facts label

The nutrition facts label identifies nutrient amounts contained in products, as well as other ingredients found in food. When looking at a food label, it’s important to consider how many servings are contained in a package. Some products actually have multiple servings as part of a single container.

As an example, this packaged food contains several servings. Why is this important? In looking at this food label you can see if you eat 1 serving, the nutrients are different from if you consumed the whole package.

With sports beverages, the recommendations to optimize water absorption includes 6% carbohydrate concentration (or 14g carbohydrate per 8oz) and 110mg of sodium per 8oz. When choosing a sports beverage it’s important to use the food label to check these amounts. In a perfect world our food packages would come in single servings and everything would be easy. How many times have you purchased a Gatorade that was only 8 oz? Probably not in a really long time. Like many products, sports beverages have multiple servings in one container.

Take a look at this beverage. You can see 1 serving is 8 oz; however, there are 4 servings in the whole container. In this label, the nutrients listed are according to an 8 oz serving. If you decided to drink the whole bottle, you would need to multiply each nutrient by 4, since there are 4 servings in this package.

In this particular drink, if you look at carbohydrates and sodium, for every 8 ounces, this drink meets the recommended sodium amounts, but falls short in the recommended carbohydrates amount. This probably would not be a good sports beverage for rehydration, even if you drank the whole thing.

Let’s look at another example: In this label, the serving size is 12 ounces. In order to determine if you are getting adequate carbohydrates and sodium for hydration, there are

some simple calculations to help figure that out. Follow the formulas below:

serving size (oz) x 14g carb ÷ 8oz = amount of carbs per 8 oz
serving size (oz) x 110mg sodium ÷ 8oz = amount of sodium per 8 oz

Let’s apply these calculations to this nutrition label. Take note of the following:

Remember:

Target carbs to have: 14 grams per 8 ounce serving
Target sodium to have: 110 mg per 8 ounce serving
Serving size: 12 oz

To determine if this meets your carbohydrate needs:

12 ounces x 14 grams ÷ 8 ounces = 21 grams of carbs

This meets carbohydrate needs

To determine if this meets your sodium needs:

12 ounces x 110mg sodium ÷ 8 ounces = 165 mg sodium

This meets sodium needs

What about the % Daily Value column? What does this mean? Some may mistake the percentage shown on the same row of the nutrients for the concentration of the nutrient in the food. The % Daily Value shows how much of a nutrient in a serving of food contributes to a total daily diet, NOT ITS CONCENTRATION.

Now you know how to choose a sports beverage to optimize hydration. But how can you access your hydration status?

How can you tell if you are well-hydrated during exercise?

Here is a simple activity that you can do to see if you have consumed enough fluids when exercising.

Measure body weight just before beginning to exercise.
Measure how much fluid (in oz) is consumed during exercise.
Measure body weight immediately after completing exercise.
The difference in weight is the fluid that should have been consumed, but was not
A greater than a 2% difference in weight is likely to compromise the benefits derived from the exercise.

If this seems like a lot of work for you, don’t worry! The urine color chart shown below is a more convenient way, though less accurate, to access your hydration status.

Here are some additional suggestions on Fluids and Hydration | US Anti-Doping Agency

GUIDELINES FOR FLUID REPLACEMENT

The following guidelines for maintaining body fluid balance, improving performance in the heat, and preventing heat-related illness appear to be prudent based on current scientific knowledge.

For intense training and long workouts, a fluid replacement drink containing carbohydrates may provide an important source of energy. A 6-8 percent carbohydrate beverage is typically most effective in maintaining fluid balance while supplying the muscles with fuel.
The fluid consumed during activity should contain a small amount of sodium and electrolytes. The sodium may be beneficial for quicker absorption and replacement of sweat loss.
The beverage should be palatable and taste good.
The athlete should drink 7-12 ounces of cold fluid about 15-30 minutes before workouts. If the workout is prolonged, add carbohydrates to the beverage at a 6-8 percent concentration.
Drink 4-8 ounces of cold fluid during exercise at 15-20 minute intervals.
Start drinking early in the workout because thirst does not develop until 2 percent of body weight has been lost, by which time performance may have begun to decline.
Avoid carbonated drinks, which can cause GI distress and may decrease the volume of fluid consumed.
Avoid beverages containing caffeine, alcohol, and those promoted as energy drinks.

Physical activity is important to include as part of a healthy lifestyle. Not only can it be an enjoyable hobby it can positively contribute to overall physical and mental health. Making sure you are meeting your body's needs to optimize the benefits is important when engaging in prolonged physical activity. Remember to drink mindfully while exercising!

Content contributed by Yuyi (Amber) Chen currently a bio-major student at Emory University. Originally from Hangzhou, China, Yuyi has been studying in the US for 8 years. Yuyi is interested in nutrition and hopes to use her knowledge to help people maintain a healthy lifestyle.