Sugar has been the center of a lot of negative press over the last decade, and for good reason. Diets high in added sugar are associated with increased risk of obesity, type 2 diabetes, and cardiovascular disease. Added sugar is also known to lead to a “sugar high,” followed by the crash, which is a result of a quick increase in blood sugar from the surge of glucose and then a drop an hour or two later (or sometimes even more quickly). Controversy over whether or not sugar should be regulated more closely by the government has heated up in the last two years, and some public health advocates and researchers believe it to be toxic and it should be treated like tobacco or alcohol. Regardless of the politics of sugar, limiting added sugar in a diet is beneficial to overall health.
With that said, athletes may not need to worry as much about sugar as the general public, especially when it comes to the sugar high and crash. Endurance exercise leads to many positive physiological adaptations including the body’s response to glucose (the building block of sugar). During exercise, the body becomes more sensitive to insulin, the hormone responsible for bringing glucose into the cells, especially those in the muscle. Thus, the body needs less insulin to get glucose to the working muscles and can handle sugar better. Research has actually shown that exercise is one of the most effective ways to improve insulin sensitivity and reduce incidence of type 2 diabetes, absent of dietary changes. It’s even been shown to be more effective than pharmaceuticals.
Even better, research suggests that trained athletes are better able to use sugar in general, not just during exercise. Athletes’ response to a glucose tolerance test indicates a significantly better use of insulin and greater ability to handle glucose than their untrained counter parts. It’s also been shown that after 10 days of rest, athletes’ ability to handle glucose didn’t change; however, their bodies did produce more insulin after the 10 days of rest in order to metabolize the same amount of glucose. Exercise may also reduce the body’s natural deterioration of glucose tolerance that comes with aging.
What does this mean for runners?
The important take away here is to understand that an athlete’s response to sugar is different than the average untrained individual. Therefore, a glass of orange juice in the morning (which also includes essential nutrients), the added sugar in a fruit filled yogurt, or an occasional cookie isn’t going to send your body into a huge sugar high and crash.
While it’s important to limit added sugars for overall health and weight management, especially if they are replacing foods with essential nutrients, as athletes you don’t need to be as worried about added sugar in your diet as the general public. Also remember that added sugar is sometimes beneficial to your training. During long runs, you want carbohydrates that are quickly absorbed and sugar does the job.
How much sugar is OK to eat?
The World Health Organization (WHO) recommends that no more than 10% of your calories come from added sugar. So, if you are eating a 2,000 calorie diet – about 200 calories can come from added sugar per day. This doesn’t include sugars naturally found in food such as fruit or 100% juice. But, remember this does include things like gels and sports drinks. So if you consume 2 gels on a long run – that is 200 calories of added sugar.
Keep in mind that to maintain weight, calories are what matters most. Added sugar contributes to your calorie intake (4 calories per gram of sugar) and will not keep full for as long as other forms of carbohydrates that include fiber and are therefore digested more slowly.
Do you know how much added sugar you consume on a daily basis? Do you try to avoid all added sugar? What are your thoughts on the current sugar debate?
(Sarah holds an MS in Nutrition Communication from Tufts University Friedman School in Boston. She is working towards becoming a registered dietitian and will begin her dietetic internship at The Brigham and Women’s Hospital in Boston this fall. Sarah is a certified spin instructor and an avid runner and regularly participates in road races from 5k to a 1/2 marathons. Follow her on Twitter @SpinnerSarah and at her personal blog Food and Fitness Friend .)