A fasted workout is when you exercise on an empty stomach, typically first thing in the morning, having fasted overnight whilst sleeping. Should you skip breakfast before picking up a barbell? Should you eat your breakfast before hitting the Boxing Fitness Equipment? Learn the pros and cons of fasted workouts in our blog.

Safety First!

It is essential to consider your goals, lifestyle, overall health, and preferences before making drastic changes to your eating habits.

Fasted workouts are not suitable for everyone, especially those with health conditions, women that are pregnant or breastfeeding, if you suffer from low blood pressure, have dietary restrictions, or are an athlete with specific training goals.

Always listen to your body and consult with your doctor, a healthcare professional or fitness expert before incorporating fasted workouts into your routine.

Benefits of Fasted Workouts

• Convenience - Getting up early enough to eat and fully digest a breakfast before a 6am gym session is not something that most people are willing to give up their sleep for. Working out fasted and then having breakfast means that sleep doesn’t have to suffer as a consequence.

• Improved Metabolic Flexibility - Regular fasted training can enhance the body's ability to switch between burning carbohydrates (the preferred source) and fats for fuel, improving metabolic flexibility over time.

• Enhanced Glucose Tolerance and Increased Insulin Sensitivity - Research has shown fasted exercise can improve insulin sensitivity and improve glucose control.

• Weight Management or Weight Loss - Whilst fasted training may enhance fat oxidation, it does not result in greater overall weight loss, decreased fat mass or changes in lean muscle, when compared to fed training of equal calorie intake. Nor does it ‘Boost metabolism’. Weight loss depends on creating an overall calorie deficit through diet and/or exercise, the timing of eating has no significant impact.

Downsides of Fasted Workouts

• Muscle Loss or Damage - Muscle tissue breakdown rapidly accelerates after fasted training and without sufficient fuel, the body is at higher risk of injury. Glycogen depletion can also impair the body's ability to repair and rebuild muscle tissue post exercise.

• Increased RPE - Exercising on an empty stomach may increase the rate of perceived effort of the workout, which may cause you to enjoy your exercise sessions less. You may find that your 12.5kg Dumbbells feel more like 15kg Dumbbells.

• Increased Perceived Reward - It can create a mindset of earned recovery fuel, which can negatively influence the size and nutritional value of the post workout meal.

• Potential Disordered Eating Patterns - Diet and exercise are complicated topics, and it is always important to remember that, if you are struggling with disordered thoughts, help is available from Eating Disorder or your GP.

• Potential Nutrient Deficiencies - Skipping a meal can potentially lead to inadequate nutrient intake throughout the day. For those aiming to build muscle, protein synthesis is optimally supported every 3-5 hours. Skipping breakfast is missing a window of opportunity.

Fasted Cardio vs Fasted Strength Training

For both strength and cardio training, the effectiveness of fasted workouts depends on factors such as duration and intensity.

Fasted steady state cardio, such as zone 2 on a stationary bike, can improve metabolic flexibility and VO2 max by increasing fat oxidation. It can help spare muscle glycogen and improve oxygen delivery to muscles, enhancing performance for endurance athletes.

In comparison, fasted high-intensity cardio such as sprints on the air bike, will cause heightened cortisol levels, have a catabolic effect on muscle tissue, and have a detrimental effect on both performance and recovery.

When using barbells and dumbbells, many would argue they feel weaker if they haven’t eaten. However, during periods of repeated fasting, such as during Ramadan. Being fed doesn't necessarily correlate with power, and fasted strength training hasn't shown to be detrimental.

However, it is not ideal for hypertrophy as muscle protein breakdown accelerates after fasted training. This will slow both muscle building and recovery.  Fret not, this can be countered by eating a meal high in protein and carbohydrates within a few hours of training.

Should Men and Women Do Fasted Training Differently?

Men and women may respond differently to fasted training due to variations in hormone levels, body composition, and metabolic rate. For instance, men typically have more muscle mass and less body fat, affecting fuel utilisation and energy expenditure during exercise.

Women's unique physiology makes them more prone to energy imbalances when fasting, especially when combined with intense exercise. This can disrupt hormonal balance, potentially leading to issues like elevated cortisol levels, impaired thyroid function, and irregular menstrual cycles.

If training fasted works for your lifestyle and is giving you results, fantastic. If training fully fueled works for your lifestyle and is giving you results, that’s also fantastic! If you want to train fueled, but don’t have time to have breakfast before you exercise, try something like an electrolyte and carbohydrate drink, or experiment with training later in the day if your schedule allows.

Written by our guest author Chelsea MacColl.

For more content, follow us on Instagram, YouTube, TikTok, and on our official Mirafit Facebook page.

Tags: Misc > Lifestyle