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The Dos And Don'ts Of Workout Nutrition

By Justin Sorbo

From Bob. B: “What is the best strategy for managing food 2 hours before and 2 hours after a workout (or whatever pre/post timeframe makes sense, if it is one hour before/after, then fine). For example, is fasting best? Or is fruit best? Or protein? Is one better before and one after? Or does it not matter? I go for a protein bar within an hour after, but I'm not sure it is right. For me for before, it tends to be whatever my normal breakfast is. But if I should have a fruit one hour before for some carb, I could easily do that.”

This is the first of a multi-part series where I’ll address Bob’s questions piece by piece.

2 Hours Before: Nutrition For Performance, Pre-Workout

Pre-workout nutrition is context dependent. It varies regarding the timing of your other meals, your metabolic health, your time constraints, and the duration, intensity, and type of exercise performed. Are you going for a 10 mile run or are you lifting heavy weights for an hour?

Consider the latter option first. Let’s define performance as the biological ability to do a given task optimally for a given time frame, intensity, and number of repetitions. For example, in a strength workout: having enough fuel to complete a given number of sets and reps at X intensity relative to maximal output. If your goal is to do 5 sets of 8 reps of bench press at 90% of your 8 rep max, optimal nutrition would not become a limiting factor in completion of those sets. Strength training primarily relies on two metabolic pathways: PCr and Anaerobic Glycolysis (explained on the next page). Endurance relies on different pathways, which I’ll address in an upcoming article.

For your muscles to contract with enough force over time to move the most weight possible, there must be ample availability of carbohydrate and creatine. Creatine is present in everyone’s muscle cells (you can supplement to get more of it - let’s discuss later). The body stores the most carbohydrate in muscle tissue, with some extra reserve in the liver and the brain. If you eat a diet with a reasonable amount of carbohydrate in most meals, you’ll have plenty of muscle glycogen to perform your best in a workout, regardless of what you’ve eaten immediately prior. Even if you’re on a low carb diet, your body will make carbohydrates from other sources, though not as efficiently. Eat according to “feel” - whatever you like that doesn’t upset your stomach or give you brain fog.

If you’re working out multiple times per day at a high intensity, pre-workout nutrition becomes more important. You might need to replenish your glycogen stores before your next workout, so consider eating a mixed meal (protein, carbs, fats, and vegetables) 1-3 hours prior to training. The bottom line: for most people eating a balanced diet, pre-workout nutrition is next to irrelevant for performance in a strength training workout!

How It Works: Supply, Demand, And A Bunch Of Banks

Energy systems run like a function of economic supply and demand: Movement creates energy demand, and your body has to find a way to feed that demand to satisfy the market. In order to move (or to be alive, sleep, or rest), your body needs energy in the form of ATP (Adenosine Triphosphate), the energy currency of the human body. Remember 6th grade biology? Me neither. Ultimately, the food you eat is composed of macronutrients (protein, fat, carbohydrate) that will be stored and/or metabolized into fuel for biological processes.

There are 4 methods of creating ATP (energy currency $) that run 24/7 with various levels of reliance, depending on the rate and duration of demand for energy during a given task. You might think of them as the cash-producing assets of the body. They are as follows (#1 and #2 are most important for strength training):

  1. PCr (No, not that one - Phosphocreatine): Makes ATP the fastest, but yields the least. Primary source for high intensity exercise up to 10 seconds in duration. When you need money fast, PCr delivers. No oxygen involved. Strength training relies heavily on PCr and it takes the longest to regenerate (hint, hint: this is why you rest in between sets of strength training, even though you’re not out of breath).

  1. Anaerobic Glycolysis: Makes ATP from carbohydrate without oxygen. Primary source for high intensity exercise from 10-30 seconds. Makes more ATP than PCr, but does it a little slower. Carbohydrates stored in muscle tissue (glycogen) provide the fuel to for AG.

  1. Aerobic Glycolysis/Krebs Cycle: Makes more ATP, albeit slower than the prior two. Carbs and fats are the bank for this one. Longer duration exercise (endurance events) rely heavily on this system. Needs oxygen to function. The Krebs Cycle converts lactate (a by-product of glycolysis) to be used in the final boss of ATP generation, listed below.

  1. Electronic Transport Chain: The slow king of ATP, and the big bank for all endurance activities. Makes tons of ATP very slowly, with the help of oxygen. Carbs and fats are the fuel, with a little help from protein.

Whatever the demand, your body’s energy systems have an answer. Eat a balanced diet with protein, carbohydrates, and fats, and you’ll be covered to perform your best in your strength workouts. In my next edition, I’ll cover recovery and protein requirements for optimal health and performance.

Got questions? Send me an email

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