Many years ago, I became fascinated with digestion and its effect on performance. Not long afterward, we began using a phrase that I still refer to today: Gastric Emptying.

Simply put, gastric emptying is the process—and the rate—at which food leaves the stomach and moves into the small intestine, where the majority of nutrient absorption takes place.

And when you’re concerned with training and performance, that timing can matter considerably.

Admittedly, it initially led me to more questions than answers. But the main question was ultimately this:

Is your pre-training meal competing with your supplements?

That question came back to me this morning.

At 0700, I ate a roughly 300-calorie blueberry, oatmeal, banana and egg pancake with a tablespoon of natural peanut butter and a tablespoon of raw honey. A relatively small meal.

Carbohydrate. Protein. Fat. Fiber. And each of those components can influence digestion differently.

The honey provides rapidly available carbohydrate. The banana, blueberries and oatmeal provide additional carbohydrate along with fiber. The eggs and peanut butter contribute protein and fat, which can slow gastric emptying.

That led to two questions: how long should I wait before taking my pre-training supplements? And—when are the nutrients from that meal actually available to fuel my training?

Those aren’t necessarily the same question.

Gastric Emptying Isn’t an On/Off Switch

This is where our understanding of digestion needs to become a little more sophisticated.

Food doesn’t sit completely untouched in the stomach for two or three hours and then suddenly move into the intestine. Digestion is a process.

As the stomach mechanically and chemically processes a meal, portions of that meal are progressively delivered into the small intestine. Absorption is therefore already occurring while gastric emptying continues.

That means some of the carbohydrate from my breakfast can already be contributing to circulating glucose while other components of the meal are still being digested.

The stomach doesn’t have to be empty for the meal to begin contributing to performance. And that’s an important distinction.

Not All Meals Empty at the Same Rate

Meal size matters. Composition matters. Fat matters. Fiber matters. Protein matters. Even the physical form of the food matters.

Generally, a small carbohydrate-dominant meal will leave the stomach faster than a large meal containing substantial amounts of protein and fat.

So saying, “Food takes X hours to digest” isn’t particularly useful.

• What food?
• How much?
• What was eaten with it?
• And what are we trying to accomplish afterward?

Those are much better questions.

Now Let’s Add Supplementation

But here’s where it gets interesting. As an example, let’s start with L-Tyrosine.

L-Tyrosine has become an important part of our pre-training supplementation because it serves as a precursor to the catecholamines dopamine, norepinephrine and epinephrine—neurotransmitters involved in alertness, attention and the body’s response to physical and mental stress.

That’s why we’re interested not simply in taking it, but in creating favorable conditions for its utilization.

Tyrosine is a large neutral amino acid. And it isn’t traveling alone. Other large neutral amino acids derived from dietary protein can use overlapping transport systems, including transport across the blood-brain barrier.

Consequently, swallowing tyrosine immediately alongside a substantial protein meal may not be the ideal strategy if our specific objective is increasing tyrosine availability to the brain.

But there’s another important lesson here: context matters.

My breakfast wasn’t six eggs and a large steak. It was a roughly 300-calorie pancake containing a relatively modest amount of protein, plus one tablespoon of peanut butter and honey.

So while amino-acid competition may still exist physiologically, its practical significance isn’t necessarily the same as it would be following a large protein-heavy meal.

This is where physiology has to meet reality. Dose matters. Meal size matters. Composition matters. Timing matters.

So What Did I Do?

My practical schedule looked something like this:

At that point, I don’t need breakfast to have completely cleared my stomach. That’s not the objective.

I want the meal sufficiently progressed through digestion that carbohydrate and other nutrients are becoming available while simultaneously creating reasonable separation between dietary protein and supplemental tyrosine.

Timing Doesn’t Have to Be Perfect

There’s another side to this that I think is important.

We can become so obsessed with optimization that we make something relatively simple unnecessarily complicated.

The difference between taking a supplement at 8:47 and 9:03 probably isn’t determining the success or failure of your training program.

We’re looking for useful physiological windows, not magical minutes on a clock.

Understanding gastric emptying simply gives us another tool for arranging nutrition, supplementation and training intelligently. And once you understand the underlying mechanism, you don’t have to memorize somebody else’s schedule.

You can make informed decisions based on your meal, your supplements and your training.

That’s really what fascinated me about gastric emptying all those years ago. It wasn’t simply how long food stayed in the stomach. It was realizing that what we consume, when we consume it and what we ask our bodies to do afterward are all connected.

Nutrition doesn’t occur independently of training. Supplementation doesn’t occur independently of nutrition. And training doesn’t occur independently of either one.

They’re interacting systems. Understanding those interactions allows us to stop merely consuming things—and start timing them with intent.