Nutrition, Whole Health

Fasted vs Non-Fasted Exercise: What Works Best?

Eating Before a Workout – Should one exercise on an empty stomach (fasted) or have a snack beforehand?

The table below descries the differing scenarios.

Training Type

Non-Fasted

Fasted

Endurance Athlete:

* Training Low,  low glycogen (energy) stores.

NO

To improve metabolic efficiency: body will adapt to use fat for fuel (can go longer before ‘hitting the wall’).

The desired effect is not immediate.

Maximize performanceEat before exercise: have snack/meal high in carbs, low fat with some protein:

Maintains energy & delays fatigue; augment performance, stay sharp; maintain blood sugar.

NO

Strength and muscle gains (hypertrophy- increase muscle size)Eat a meal with protein (easily digestible) & carbs before workout for energy needed to perform & to increase muscle mass.

NO

High Intensity Interval TrainingNeed carbohydrates for fuel.  Also, need nutrition to maintain/gain muscle mass.  Otherwise body will break down lean tissue (muscle) for energy.

NO

Weight Loss Helps to ‘burn fat’  BUT  also need to be mindful of caloric intake for the rest of the day.  Do not overeat afterwards.
Make sure to eat after exercising to rebuild muscle and reduce muscle soreness.  Consume carbohydrates and easily digestible protein, but not fat. Fat does not digest quickly so it would not be accessible for recovery.
*Rikki Keen, MS, RD, a certified specialist in sports dietetics and certified strength and conditioning specialist says, “science has shown placing the muscle in a stressful state of low glycogen levels during selected aerobic training sessions can trigger a cascade of hormonal and gene signaling that further enhance training adaptations within the muscle cell.”

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