The Over/Under on Performance

Overtrained or underfed: How to tell the difference, and what to do to get back on track.

Let’s say you have a friend who has been training consistently for a long period of time. She never misses a workout, and every time she trains, she works at a high intensity, pushing herself to that red line day after day. After several months, she complains about feeling unmotivated, fatigued and irritable, and she expresses concern about her plateaued progress, trouble sleeping and a persistent soreness that rarely abates.

Are you overtraining, or under-fueling?

The Over

Given these symptoms, you’d likely identify her issue as overtraining, and indeed this could be the culprit. Overtraining occurs when the volume and frequency of your activity exceeds your recovery capacity, either from programming that progresses too quickly or from boosts in training volume that last for extended periods without allowing for adequate rest and recovery. Overtraining causes oxidative stress, which is a natural part of exercise as your body metabolizes oxygen to produce energy and encourage cellular repair. This process also produces free radicals, which are normal to some degree. However, with overtraining, the number of free radicals produced overwhelms the repair processes and can damage cells, DNA and mitochondria, causing inflammation, muscle fatigue and soreness that negatively impacts performance.

The Under

But before you diagnose your buddy as overtrained, there is another factor that could be at work: under-fueling. Under-fueling occurs when you take in fewer calories than you need in order to sustain a particular activity at a particular intensity over a period of time. This is not the same as restricting calories in order to lose weight because under-fueling is not done purposefully. It is usually a misunderstanding of your actual nutrient needs as they relate to your training protocol. As with overtraining, your symptoms will slowly compound if your workouts increase and your nutrition stays the same or if you are following a meal plan not suited to your activity. For example, an endurance athlete who suddenly switches to a low-carb diet without accounting for the amount of fuel she needs will likely perform poorly until her nutritional needs are addressed.

The Verdict

So how do you determine which ails you — overtraining or under-fueling since the symptoms are so similar? It is difficult, but the things that stand out with under-fueling are a noticeable loss of lean muscle mass, frequent illness and the loss of your menstrual cycle.

The good news is that both conditions are preventable. If you think you’re overtraining, rein in your training a bit and allow for some days off. Adopt a periodized plan that rotates between light, moderate and heavy volume/weight-training schedules, and get plenty of sleep and recovery time. If you suspect you’re under-fueled, track your food in a diary for several weeks and ensure you’re at least meeting your basic metabolic needs, as per the formula below. This has been shown to be most accurate and is as follows for women:

10 x your weight (kg) + 6.25 x your height (cm) – 5 x your age (years) – 161 = REE (resting energy expenditure)

Once you’ve determined your REE, multiply that number by the appropriate activity factor below to determine the number of calories you need per day:

  • Light – 1.56 
  • Moderate – 1.64 
  • Heavy – 1.82

Make sure you hit that target daily in order to keep your training on track and your progress moving forward