5 Nutrition Mistakes Runners Make

By Jen Rawson, RD

Nutrition mistakes occur to everyone—from newbie runners to seasoned athletes. Making mistakes and adjusting them is often how we learn what works best for our body. But if you can avoid a few of these common nutrition mistakes, you might just save yourself some time and energy.

Losing Weight to Improve Speed

Many runners aim to lose weight to improve their running performance.  A commonly cited statistic is a runner’s pace increases 1.5-2 seconds per mile for every pound lost (above their ideal body weight). This is based on small-scale studies where trained participants either had weight added to them via harnesses or subtracted via pulleys.1,2 Unfortunately, these studies artificially added or subtracted weight, which does not consider the realities of losing weight.

To lose weight, you must be in a calorie deficit and when in a caloric deficit the body does not build muscle. In fact, it often loses muscle mass and preserves fat mass. Trying to increase speed or power with decreased muscle mass proves challenging for most runners leading to frustration from not seeing the promised results. Cutting calories in the pursuit of weight loss may also come at the expense of training as it impacts energy levels and muscle recovery.

A better strategy for improving performance would be nourish the body appropriately, fuel for recovery, and follow a plan built for speed.

Using Running as a License to Eat

What runner hasn’t said, “I ran X number of kilometers today, so I deserve this "cupcake” or “I earned this plate of nachos”? The problem with this line of thinking is that most people overestimate their exercise burn and underestimate their food intake often leading to the mysterious weight gain many runners experience.

Only allowing yourself food when it’s “earned” can be problematic for your relationship with food and exercise. All food can fit into the diet when you focus on fullness and satisfaction and not calories burned. And running or any exercise should be for the benefits such as the joy of movement, the feeling of accomplishment, improved health, or stress relief and not for earning food.

Eating Too Many Carbohydrates and Not Enough Vegetables

Carbohydrates belong in a runner’s diet. They are a runner’s primary source of fuel. Plus, they provide valuable nutrients such as fibre, vitamins, and minerals; not to mention they bring satisfaction and enjoyment. Endurance runners particularly need a higher proportion of carbohydrates in their diet however when carbohydrates take over the vegetable portion of a plate you miss valuable antioxidants important for recovery.

A balanced plate should contain about ½ plate vegetables, ¼ plate protein foods and ¼ plate whole grains. An endurance runner can maintain these similar proportions and increase the size of the plate or add in high carbohydrate snacks pre and/or post-exercise to meet their increased carbohydrate needs.

Relying Too Heavily on Sports Nutrition Instead of Real Food

Sports nutrition products like gels, gummies, protein powder, sports drinks, etc. have a place in a runner’s world as convenient sources of nutrition.  However, supplements can never match the benefits of real food. Choosing sports supplements over food comes at a premium price to both your wallet and your body.

Sports supplements may meet your carbohydrate or protein needs, but they lack the complexity and diversity of nutrients found in food and can lead to excess intake of sugar, artificial sweeteners, and sodium. For example, drinking a sports drink after a long run replaces your carbohydrate and electrolyte needs but a banana with peanut butter and water would do the same and contains fibre, protein, and vitamins. Choose sports supplements for convenience when training long distances or when on the go but opt for real food to meet your needs as much as possible.

Waiting Too Long to Eat After a Run

Eating post-run is important for recovery but also for managing hunger and eating habits. Runners often don’t feel hungry right after running but wait too long and the hunger catches up. When you become over-hungry, you are much more likely to reach for quick convenience foods that often have less nutritional value than a balanced meal. This cycle will happen to everyone occasionally but if it becomes a pattern, it can lead to improper recovery.



  1. Cureton, KJ, et al. “Effect of experimental alterations in excess weight on aerobic capacity and distance running performance.” Med Sci Sports, 10,3(1978). 194-199.


  1. Zacharogiannis, E, et al. “The Effect Of Acute Body Mass Reduction On Metabolism And Endurance Running Performance.” Medicine & Science in Sports & Exercise, 49,194(2017).