Rule 2: Get most of your calories after your workout
There are two reasons for this.
1) Resistance training (i.e. lifting things up and putting them down) improves something known as “insulin sensitivity.”
As explained above, insulin is an anabolic hormone. So with increased sensitivity, more of the calories you consume will be used for building muscle, rather than storing fat. Because of this, you’ll get the most bang for your proverbial buck by saving your food for after your workout.
2) Lifting while your body is in a “fed” state may decrease your workout performance.
Digestion, like any other body process, takes a bunch of energy. Think about how you felt immediately after Thanksgiving dinner: tired, gluggy, or comatose are all probably apt descriptors. That’s because your body was diverting energy to the digestion process, thereby reducing available energy for your other body functions.
Sure, not every meal is as extreme as this. But a similar competition for energy goes on all the time. Because of that, saving more of your eating for after your workout may actually leave you with more energy than if you had a preworkout meal, and it may even be better for building muscle.