Should You Work Out On An Empty Stomach?

You’ll probably already know that nutrition is key to achieving your desired body and maintaining fitness. Choosing the right food and preparing your pre and post-workout meals is as crucial as your exercise routine.

But what if we subtract a bit of nutrition from the equation?

Many people advocate for fasted workouts or working out on an empty stomach. Many have reported achieving excellent results in weight loss and body recomposition. But does this routine work, and is it the right one for you?

This article will discuss the scientific benefits of fasted workouts and guide you on how you can safely apply them to your training.

Your body relies on critical macronutrients for energy- these are your carbohydrates, proteins, and fats.

Your body taps into your reserved carbohydrates or glycogen for quick fuel during physical activities such as exercising and playing sports.

If stored glycogen is depleted, especially when you fast or exercise on an empty stomach, your body will begin to burn fats instead to power up your cells.

In theory, this whole process will result in significant fat loss within a few weeks if you can sustain it.

Most studies define fasted workouts as not eating before a workout for 8-14 hours, commonly performed in the morning before breakfast.

Generally, fasted workouts are safe. But it is vital to consult your doctor if you have metabolic conditions such as hypoglycemia or diabetes before trying this major routine.

It is also best to remember that each person has different reactions to metabolic changes in their body. Some experience boost in mental clarity, allowing them to focus on their exercises, while others feel unmotivated and experience a drop in strength, thereby affecting the quality of their exercises

You may also feel lightheaded or nauseous during the first few days of being in a fasted state since your body is still adapting to its new energy source.

Before trying this method, it is best to have the right mindset.

Fasted workouts should be done with the intent of long-term adaptation in your metabolism, not just for immediate benefits.

“Essentially, this routine trains your body to use and break down stored fat faster and more efficiently over time.”

Making your body shift to fat as your primary energy source can be quite challenging, especially if you are not used to fasting. If that is the case, you may have less energy and be unable to perform with 100% effort during your training.

Because of this, a burst of high-intensity exercises can be beneficial for you to maximize your training before running out of gas.

If high-intensity exercise is too taxing for your body, especially in the first few days of fasted workouts, trying steady-state cardio or jogging for 30-45 minutes in the morning on an empty stomach is also a good start.

Although the evidence is quite conflicting, here are some of the possible benefits of fasted workouts:

Fat loss is a significant benefit of fasted workouts. For example, one study found that those who work out on an empty stomach before breakfast burn a whopping 20% more fat than those who take pre-workout meals or breakfast.

This is primarily due to a dramatic drop in insulin levels when you fast, allowing your body to tap on your stored fat and break them down.

Growth hormone (HGH) is naturally released in the body in short bursts throughout the day. This hormone is responsible for various developments in your body, such as muscle growth and utilization of stored fats.

Studies show that exercise and fasting both lead to significant spikes of growth hormone in the body, allowing you to reap the benefits of a boost in HGH, such as weight loss, an increase in muscle strength, and many more.

Fasting results in an overall increase in insulin sensitivity. This means that your cells become more efficient in using glucose in your blood and reduces blood sugar levels. This could be beneficial for people with diabetes if their doctor recommends it.

Here’s a workout you should try fasted:

Performing fasted workouts trains your body not to rely on glucose for energy. Long durations of fasting put the body in a metabolic state called ketosis. This means that your body starts producing ketones from the fats in your body.

Ketones are a natural source of fuel, and unlike fats, ketones can cross the blood-brain barrier allowing them to fuel both the brain and the body. Compared to glucose and fat, ketones are more efficient in providing more energy while using less oxygen.

Over time, this can translate to increased mental performance and strength.

Fasted cardio and fasted workouts may increase your long-term endurance levels (VO2 Max). A study involving endurance athletes, those who perform fasted cycling have significantly increased their VO2 Max and resting muscle glycogen concentration.

One of the downsides of fasted workouts is the chance of muscle loss. During a fasted workout, the body doubles the protein breakdown in our muscles, and this could hamper your gains if you are building muscle mass.

Ensuring that you are maintaining your protein needs every day is essential to counter this effect. Eating at least 1g of protein per lb of your body weight to prevent muscle loss is ideal. This means if you weigh 170lbs, you need 170g of protein in your diet every day.

So, should you work out on an empty stomach? It depends.

If your goal is to lose fat faster, fasted workouts can give you incredible results. However, if you are trying to build muscles, you have to optimize your nutrition to prevent muscle loss.

If your energy level is significantly lower during fasted workouts, you may benefit more from taking your pre-workout meal or breakfast.

Fasted workouts should be treated as a long-term routine and a way to train your body to use your stored fat faster and more efficiently.

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Bert Bauzon is a licensed physiotherapist specializing in spinal care and sports rehabilitation. He writes articles and books about exercise science and health care.

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