Fasted Weight Training: Fitness Pros & Cons

The worlds of fitness and nutrition run parallel to each other, crossing paths frequently and to the benefit of health enthusiasts everywhere. Whether it’s the positive effects of consuming protein on building muscle mass or taking supplements for improved muscle recovery, it’s clear that how we benefit from exercise is directly impacted by what we put into our bodies.

But how is fitness affected by what we don’t put into our bodies? Intermittent fasting has become a popular dieting method recently for health and weight loss. With the intention of losing fat and gaining muscle mass during weight training, is it possible that fasting could help with this?

Today, we’ll take a closer look at what fasting is and how it can impact your next strength training work out.

What Is Intermittent Fasting?

The results are in, and intermittent fasting is on a steady incline in popularity for its reported weight loss and health benefits. There are multiple different ways to fast intermittently. Still, many participants prefer to fast for 16 hours each day or for 48 hours once per week. During this time, no food or sugary drinks are consumed.

While fasting has made a name for itself recently, it’s certainly not a new practice. Various religions have and continue to encourage fasting for numerous reasons; Greeks have also used the practice for different medical therapies since the 5th century BCE.

Some of the most common benefits of fasting are:

• Anti-Inflammatory – Chronic inflammation is a serious condition that, if left untreated, can lead to a variety of health conditions, such as stroke, lupus, arthritis, and heart disease. Studies have shown that fasting can reduce inflammation and decrease the chances of developing these health conditions.
• Blood Sugar Lowering – Those with diabetes have been increasingly using fasting to help lower blood sugar. Multiple studies have shown promise with the impact that fasting can have in helping to reduce insulin resistance and improve blood glucose levels.
• Cholesterol-Lowering – Some studies have shown that the risk of heart disease can be lowered by reducing bad cholesterol through fasting.
• Brain Health – Neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease, have shown in studies to be impacted by fasting through a possible cognitive function enhancement.
• Blood Pressure Control – Fasting has shown in some studies to help reduce high blood pressure in some adults with obesity.
• Weight Loss – One of the primary reasons intermittent fasting is used is for weight loss. The act of reducing calorie intake and increasing fluids has been shown to aid in the increase in metabolism and a boost in weight loss.

The Science Behind Fasting and Fat Loss

Fat loss is vital in the process of strength training. By focusing on the last fasting benefit, weight loss, we can take a closer look at how this directly correlates with the reduction of fat in the body. There are three ways in which fasting can directly affect your body’s metabolism to burn calories faster:

• Increase in HGH – Human growth hormone (HGH) contributes to your body’s loss of fat. When in a state of fasting, HGH levels are shown to increase, thus aiding in fat loss.
• Norepinephrine Production – Norepinephrine is used to convert fat cells into energy through fatty acids. Fasting helps speed this process up by sending norepinephrine directly to fat cells.
• A Decrease in Insulin – Insulin is shown to decrease through fasting, which in turn, helps to burn fat.

Pros of Fasted Weight Training

Fasting while weight training has key positive benefits that any strength trainer can appreciate. We’ll start with the one we just discussed, fat burning:

• Fat Burning – With the assistance of HGH, insulin, and norepinephrine levels, fasted weight training can make way for more muscle growth by actively helping with fat reduction. 
• Muscle Retention – When you’re building muscle, having an increased capability to retain the muscle you’ve worked so hard for is ideal. Some studies have shown that, through fasting, participants saw much less muscle mass loss than average. 
• Indigestion Avoidance – Through fasting, you can gain the ability to avoid indigestion. Indigestion is frequent during working out due to the decrease in the blood used to aid with digestion.
• Performance Enhancement – There have been some studies that show that fasting helps boost performance; this is possibly due to lower blood sugar levels, leading to an increase in fat burning. 

Cons of Fasted Weight Training

Just as with any critical decision, it’s crucial to weigh the cons against the pros. While there are some fantastic pros to fasted weight training, there are some definite negatives that warrant consideration:

• Performance Reduction – Just as the possibility for performance enhancement has been shown, there is a similar chance of a reduction in performance. Calories help provide energy for your body to burn. When you aren’t consuming calories during a fast period, your body can react by slowing down to conserve energy loss.
• Long-Term Fat Burning Reduction – Following a workout, your body continues to burn fat over the next 24 hours; however, when fasting, your body could see a slow down in continued fat burn due to the lack of calories being consumed.
• Muscle Mass Loss – Production of the stress hormone cortisol can be increased during a fasted state. When cortisol is present, more amino acids are sometimes burned, resulting in a reduction of muscle mass.
• Overeating – Any time you combine a reduction of eating with the simultaneous burning of calories, there’s a possibility of overeating to compensate. When over-consumption of calories happens, it can increase fat and weight levels.

As shown, there are definite pros and cons to fasted weight training. When deciding if it’s right for you, it’s essential that you consider what your weight training goals are and if fasting aligns with those goals. If you’re unsure, give it a try to see what works! Every body is unique and will react differently to different methods.