Q: I often have low energy during workouts but can’t figure out why. Could my nutrition in the hours leading up to my workout be the cause?
A: Bad days at the gym should be the exception rather than the rule. If you’re healthy and not sleep-deprived, nutrition could very well be the culprit behind poor workouts.
Many people think they’re set if they’ve “eaten something” before a workout and have a protein shake ready for afterward. But what did they eat and when? Eat long before your workout and you might run on empty at the gym. Eat big just before your workout and you’ll feel like napping throughout.
So what should you do?
At the very least, make sure your glycogen stores are full. Glycogen stores get depleted even while you sleep. Eat adequate carbohydrates at breakfast, and again a couple hours before exercise. If you work out on an empty stomach, a sports drink will help, but it has its drawbacks. The sugar will first serve to replenish your glycogen stores, not to feed your muscles. And if you gulp the whole bottle before your workout, you can expect to crash a half-hour or so later.
If you lift first thing in the morning, sip a sugary drink throughout your workout (and get at least 20 grams of protein afterward). At any other time, make sure you already have some carbohydrates in your system via a meal consumed approximately two hours before your workout. This meal should contain “slow carbs” — those that get digested slowly, continuously top off your glycogen stores and provide an even source of energy.
The preworkout meal shouldn’t be too heavy. It should get digested easily enough to pass into your intestines before you start working out; otherwise, you risk gastrointestinal discomfort, such as cramping or nausea. A light meal will also make sure there is chyme in your small intestine. Chyme is a mix of gastric juice and partly digested food that can enhance the absorption of preworkout supplements and reduce the chance that they could cause gastrointestinal symptoms.
— Kamal Patel, MPH, Examine.com Director