There are 6 factors to consider when selecting your fuel choice for running or cycling. I’m going to highlight 2 of those factors in this article, and follow up with you all soon in another post highlighting the other 4 factors.
Macronutrient breakdown refers to the amount of carbohydrate, protein, and fat in the product. Quick, pop quiz – which of these is essential for us to take in during exercise?
The answer is carbohydrate! During exercise lasting over an hour or so, you’ll need to take in carbohydrates to supply your muscles with energy. For exercise lasting 1-3 hours, the recommended range is 30-60 grams of carbohydrate per hour. For exercise lasting longer than 3 hours, some athletes may need up to 90 grams of carbohydrate per hour to support the prolonged activity.
When you look at a product, check to be sure that it is a good source of carbohydrate. Look at the label and check the number of grams of carbohydrate listed in the nutrition facts. Be sure that you could picture yourself taking in an amount of that product that reaches our goal rates listed above.
Many “sports bars” targeted towards strength training athletes contain high levels of protein and low levels of carbohydrate – we want to avoid these. In fact, too much fat or protein in a product can be detrimental for endurance athletes during exercise for several reasons:
a) It slows digestion, meaning that energy might not get to your muscles very quickly.
b) It can cause gastrointestinal upset.
c) You might not get enough carbohydrate to supply your muscles if you’re eating a product with excessive fat/protein.
Factor #2: Type of carbohydrate
Your body can only absorb so much of any one type of sugar at a time. It’s important that your fuel choices contain multiple types of carbohydrate in order to maximize absorption of those sugars, as well as reduce the chances of gastrointestinal upset. Most engineered sports products are formulated with multiple types of sugars. You might notice the labels say it has a “2:1 glucose: fructose ratio” or “multiple transportable carbohydrates.”
You can also check the ingredient list to look for multiple types of sugars/carbohydrate. Look for words like glucose, dextrose, fructose, sucrose, maltodextrin, honey, etc. Here are a few notes that may help you navigate your way through some confusing terms:
- Dextrose and pure corn syrup are both 100% glucose (so both are the same type of sugar).
- Sucrose is another word for “table sugar” – comprised of 50% glucose and 50% fructose (so it has 2 different types of sugar in 1 ingredient).
- Honey is 30% glucose, 40% fructose, and 20% water.
- High fructose corn syrup is typically 45% glucose and 55% fructose (data on HFCS is controversial in terms of health - it's your personal choice whether or not to use during exercise).
- Agave nectars contain between 70-90% fructose and 10-30% glucose (yes, agave contains more fructose than HFCS! Keep in mind using almost all fructose can contribute to GI upset, so I’d recommend avoiding products with agave)
- Maltodextrin is a polysaccharide comprised of several repeating glucose molecules (1 type of sugar). Because maltodextrin comes in a chain of sugar molecules, it does have a lower osmolality compared to other products which can help reduce GI upset in some people. It’s also often used in products because it’s less sweet so you avoid that ‘sickly sweet’ flavor present in some products. Ideally, it should be combined with another type of sugar in order to promote maximal absorption and energy production. Some companies do combine it with another source; others don’t.
Contrary to popular belief, maltodextrin is actually broken down very quickly and easily absorbed – similar to the rate of pure glucose. It is not a “slowly released carbohydrate.” And this is fine, because we actually don’t want a slow release during exercise – we want quickly absorbed carbs that supply our body with energy immediately. Because the insulin response is blunted during endurance exercise, we are not worried about large insulin spikes causing a sharp drop in blood sugar levels. Instead, we should be focused on getting quick, easily digestible carbohydrates regularly throughout exercise to provide a continuous supply of energy to the muscles.
Lastly, an important note related to ingredients - real food products are highly underutilized in sports nutrition! Regular foods like bananas, raisins, dried cranberries, candies (sweedish fish or jelly beans), or fig newtons are all carbohydrate rich choices that naturally contain different types of sugars. Multiple research studies prove that raisins and bananas work equally well compared to sports nutrition products in terms of performance. In addition, regular foods are often cheaper and more readily available.
Stay tuned as I highlight the other 4 factors in an upcoming article!