Intermittent fasting (IF), once considered a radical approach to dieting, has now firmly established itself in the mainstream. The collective experience of millions, supported by robust scientific evidence, has demonstrated IF’s effectiveness in safely shedding body fat. However, a lingering question remains – how should one approach exercise while fasting? Is it safe to maintain your usual workout intensity when energy levels are low? Should exercise be restricted to feeding windows? And what type of exercise – cardio or resistance training – is most beneficial during a fast?
As a seasoned personal trainer who has embraced and advocated for the intermittent fasting lifestyle for over a decade, I have delved into the intricacies of how fasting impacts exercise and how individuals should tailor their workouts accordingly. If you’ve been seeking guidance on how to optimize your fat loss results through exercise while intermittent fasting, you’ve come to the right place. In this article, I will share the specific workout routines that I have successfully recommended to my clients to enhance their gains while fasting.
Fasted Cardio Workout:
During fasting, your muscles deplete their glycogen reserves, their primary fuel source, prompting the body to turn to stored body fat for energy. Consequently, fasted workouts are known to burn more body fat compared to exercising post-meal. This was corroborated by a 2016 study where participants engaged in a 60-minute run both in a fasted and non-fasted state, with significantly higher fat oxidation observed during the fasted session.
However, working out in a fasted state may lead to reduced energy levels. Here are three highly effective steady-state cardio workouts that will keep you in the fat-burning zone without pushing your body beyond its limits:
Workout One: 25-7-2 Stairmaster
Set the stairmill to an intensity level of seven and use it for 25 minutes. This straightforward stepping workout has gained popularity for its simplicity and effectiveness in burning calories and improving cardio endurance without pushing you out of the fat-burning zone.
Workout Two: Rowing
Rowing engages multiple muscle groups and is excellent for overall conditioning. Maintain a moderate pace on the rowing machine for 30 minutes, aiming for 20-25 strokes per minute to stay within the fat-burning zone.
Workout Three: 12-3-30 Treadmill
Set the treadmill to a 12 percent incline, walk at 3 miles per hour for 30 minutes. This challenging workout targets fat burning and provides a comprehensive cardiovascular workout. I recommend alternating between these three cardio workouts on alternate days, ensuring full-body stimulation.
HIIT Feeding Window Workout:
While fasted cardio workouts focus on steady calorie expenditure and fat burning, incorporating high-intensity interval training (HIIT) can further optimize fat loss during intermittent fasting. HIIT involves brief bursts of intense exercise followed by short recovery periods, leading to a significant calorie burn and triggering the afterburn effect.
HIIT sessions should be scheduled during your eating window, after consuming complex carbohydrates and protein for energy. I recommend waiting at least 90 minutes post-meal before engaging in HIIT. One effective HIIT variation for fat loss is the Tabata Protocol, developed by Professor Izumi Tabata. Here’s a guide to a Tabata-style HIIT workout:
Select your training equipment and warm up for two minutes. Gradually increase intensity to maximum effort by the two-minute mark, then alternate between all-out sprints and brief recovery periods for eight rounds. Maintain intensity throughout and conclude with a cooldown.
Fasted Resistance Workout:
Incorporating resistance training into your fat loss regimen is crucial, especially during fasting periods to preserve muscle mass. Without adequate protein and carbohydrates, the body may break down muscle for energy. To counter this, resistance training should be strategically timed within your fasting cycle.
I recommend training each body part twice weekly while following an intermittent fasting regimen to maintain muscle mass and support fat loss. By incorporating a balanced approach to exercise within your fasting routine, you can optimize fat loss results and achieve your fitness goals effectively.
