Remember when you were a kid, and your mother made you wait thirty minutes after lunch before running around to play?
There’s a good reason to leave a window between eating and heightened activity: Your body can’t focus on digesting food when you ask it to perform other actions like active play or exercise.
Physical activity or any activity that’s stressful, including a dreaded work meeting or life event—occurs in a different physical and mental state than what you need for digestion. This stressful state is called the “fight or flight mode.” In fact, your thoughts can impair or improve salivary response, stomach acid production, enzyme secretion, and the release of gastrointestinal (digestive) hormones.
Stress responses: your brain’s job
It’s your brain’s job to decide for your body whether to divert attention to stress responses, such as when you exercise, or to nourishing functions like resting and digesting. If you’re in fight or flight mode because of a mental or physical stressor, your body will divert energy and blood flow away from the digestive process and toward other priorities like managing and responding to the stressful stimuli.
If your body senses that it needs to be on alert or handling stressors, the natural cycle of “rest and digest” is switched off, which means that autonomic (automatic or subconscious) body functions are down-regulated. Therefore, if you want to digest your food optimally, allow a mental break or “chill-out” period when switching from a stressed (fight or flight) state into a state where you are ready to rest and digest food (known as the “parasympathetic” state).
This goes against most things you’ve been told about post-workout nutrition, doesn’t it? You have likely been told to make sure you eat within thirty minutes of working out when you actually should wait until thirty minutes after your workout. What you’ve been taught is ideal for professional athletes and bodybuilders, but not for the average person.
Digestive system & Exercise
Unless you’re extremely active and need extra calories as a result, such as in the case of a coach who trains people all day or someone with a very active day job, the directive to eat within thirty minutes of a workout doesn’t apply to you. If your activity level is high, and you want to eat immediately after a workout, liquid forms are easier to digest, as they don’t require the same digestive function.
The reason we have been told to eat within thirty minutes of working out is that we may gain a metabolic advantage from calories taken in during this window of time. The problem is that it’s nearly impossible to gain this advantage from whole foods when your digestive system is still in fight or flight mode.
The average person who simply exercises regularly and does not perform any hard training as a competitive athlete takes insufficient food each day to replace the nutrients depleted by exercise. In fact, many of my clients have found that dropping their post-workout shake allows them to finally lose the fat they’ve been battling for months. Instead, they wait at least thirty minutes and continue with solid whole foods at mealtime. Without calming down into rest and digest mode, your digestive function won’t work optimally, which means decreased stomach acid production, as well as impaired (either too fast or too slow) overall digestion.
Whether you’re in fight or flight mode acutely from an intense workout or chronically from a stressful life, the fix is the same. Take a few moments—as many as you can—to relax and breathe when you sit down to eat. (Yes, I said sit down, and I don’t mean in the car while driving!) Making a conscious effort to activate the rest and digest mode so that you can eat in a calm, mindful state will help your entire digestive process run smoothly—literally.
So, relax, decompress, reset your mind, and take a few deep breaths before sitting down at the table to eat. Do your best not to eat on the run, in your car, or immediately before or after exercise.