Can You Workout on an Empty Stomach?

Can you workout on an empty stomach? It’s a common question with a lot of conflicting answers. In this blog post, we’ll set the record straight and give you the answer backed by science.


Working out on an empty stomach — also referred to as “fasted” or “restrictive” cardio — is a popular topic within the fitness community. It’s been suggested that this style of exercise has various benefits, including fat loss and improved athleticism. However, there is conflicting research about whether fasted workouts can be beneficial and safe for everyone.

This guide provides an overview of fasted cardio, including what it involves, the potential risks and benefits, and who may benefit from trying it. Additionally, advice is provided on how to safely incorporate fasted exercise into your routine if you decide to do so.

Benefits of Working Out on an Empty Stomach

Exercise on an empty stomach has become a popular trend among gym-goers, due to its promising weight-loss benefits. Working out on an empty stomach can help you burn more fat and can also help promote muscle growth. However, there are some potential downsides to working out without food. In this article, we will explore the pros and cons of working out on an empty stomach.

Improved Insulin Sensitivity

It has been demonstrated that working out on an empty stomach can improve one’s insulin sensitivity. Insulin sensitivity is related to the way the body uses glucose for energy production. This is especially important for individuals who are predisposed to metabolic disorders such as type 2 diabetes, obesity and non-alcoholic fatty liver disease. Research suggests that working out in a fasted state can increase the uptake of glucose from the food you eat by up to 20%. This results in better insulin sensitivity, which helps control blood sugar levels, reduces hunger, and increases fat burning potential. Additionally, studies have found that those who exercised while still fasting had lower levels of post-meal glycaemia and insulinaemia – both markers of healthy metabolism.

Increased Fat Burning

Working out on an empty stomach has the potential to increase fat burning and enhance performance. Research suggests that working out in a fasted state can help improve body composition and boost metabolic rate. In a fasted state, it is believed that the body will start to use stored carbohydrates as fuel, eventually leading to greater fat breakdown and a more lean physique. Your body is most likely to use stored fat for fuel during low-intensity exercise such as walking or biking. Additionally, when training in a fasted state, you may notice increased focus and mental clarity due to increased levels of noradrenaline in the blood. This can make for an optimal workout experience.

Improved Performance

Working out on an empty stomach may be beneficial for several reasons. One of the major benefits is improved athletic performance. Working out on an empty stomach forces the body to use fat stores and increases glycogen utilization, leading to improved performance during your workout. It also helps your body become more efficient at using stored fat as fuel, making it easier to burn off extra calories during a workout session. Another benefit is increased calorie expenditure, which can lead to greater weight loss over time. Research shows that calorie expenditure increases when you are working out in a fasted state compared to working out in a fed state, so this is an ideal way to get more bang for your buck in terms of calories burned. Finally, workouts on an empty stomach may also boost cardiovascular health by improving heart rate and decreasing inflammation markers in the body.

Risks of Working Out on an Empty Stomach

Working out on an empty stomach can be tempting because it can feel like you are getting a better workout in less time. However, there are risks associated with working out on an empty stomach. These risks include decreased performance, decreased muscle-building potential, increased fatigue, and dehydration. It’s important to understand the possible risks of working out on an empty stomach so you can make an informed decision about your workout routine.

Low Blood Sugar

Fasting and exercising can be a dangerous combination. When your blood sugar, or blood glucose, is low, it can lead to dizziness, weakness, and other side effects that are dangerous when combined with physical activity. Low blood sugar can cause feelings of lightheadedness which can lead to falls or other injuries due to a loss of coordination. Additionally, exercise on an empty stomach may cause electrolyte imbalances due to dehydration from perspiration and the inability of glucose in the muscles to absorb water-soluble vitamins needed for proper muscle functioning and energy production. Low levels of carbohydrates also mean increased fat deposits and slower muscle growth as well as longer recovery times between workouts. Therefore, it is important for individuals exercising on an empty stomach to properly hydrate in order to reduce these risks associated with low blood sugar levels during intense physical activity.

Low Energy Levels

When working out on an empty stomach, your body is not able to use its energy reserves effectively. Since you haven’t had enough time to digest the food you’ve eaten, your blood sugar level will likely be low. This can lead to fluctuations in your performance and increased fatigue. Additionally, a lack of nutrients will prevent your muscles from contracting efficiently and reduce the intensity of your workout.

When you don’t have enough glycogen stored in your muscle tissue and liver, your body is forced to rely more on fat as an energy source. This means that during low-intensity exercise such as walking or light jogging, muscles tend to tire more quickly than they would otherwise. Without sufficient energy resources available to sustain high-intensity activities like sprints or weightlifting sessions, overall endurance will suffer significantly.

Ultimately, exercising without having eaten prior can cause a decline in performance due to physical fatigue and lower energy levels. To ensure optimal performance during training sessions it is recommended that athletes consume complex carbohydrates 1-2 hours beforehand in order to provide the necessary fuel for their bodies throughout their training session.


Dehydration can occur when working out on an empty stomach because you haven’t had anything to drink and the activity is causing you to sweat. This can lead to dizziness, confusion, nausea and decreased performance. It’s important to drink enough water before and during your workout by drinking small amounts of water before exercise and then adding more frequently throughout. This helps ensure that you stay hydrated as your session progresses. Additionally, you should also try to stay away from diuretic beverages (such as coffee) before your workout as these can cause dehydration more quickly.

How to Safely Work Out on an Empty Stomach

Working out on an empty stomach can be beneficial for some people, as it can help to burn fat faster. However, it also has the potential to be dangerous if not done properly. It’s important to take the proper precautions and be mindful of your body’s response when working out on an empty stomach. By taking the right steps, you can safely work out on an empty stomach and reap the benefits that come with it.

Eat a Light Meal Before Working Out

Before you exercise on an empty stomach, it is important to have a snack or light meal (of around 250-400 calories) if you have been inactive for more than an hour and need energy. Eating the right type of food will not only give you ample energy and carbohydrates to fuel your workout, but also help protect your muscles. Try having a pre-workout snack like oatmeal, yogurt, or a piece of fruit such as half a banana, almonds or a few dried apricots. Avoid eating high fat snacks as they take longer to digest and might leave you feeling sluggish during your workout.

Having some protein before your workouts can also help prevent muscle damage. Consider having lean proteins like skinless chicken breasts, low-fat cottage cheese or eggs one hour before starting your workout. Your body will absorb the nutrients faster if its in liquid form; making smoothies from whey protein can be very beneficial in this regard. Adding healthy fats such as omega 3 fatty acids will provide more sustained energy throughout the duration of your workout session.

Drink Plenty of Water

Working out on an empty stomach can be beneficial and safe, as long as you take common-sense precautious. It is important to ensure you drink plenty of water before and after your workout to keep you hydrated. When working out on an empty stomach, it is important to stay hydrated. This will help prevent you from developing dizziness or nausea during a workout. Water helps supply the body with energy so drinking adequate amounts of water will help give an extra boost during your routine. It is recommended to drink 1-2 glasses of water just prior to starting your routine and make sure that you have refilled your water bottle during the 20-30 minutes in between sets. Knowing how much water you need for optimal performance can be helpful when exercising in a fasted state, as lower amounts may not be adequate for strenuous workouts.

Avoid High Intensity Exercises

When it comes to working out on an empty stomach, it’s important to avoid high intensity exercises. High intensity workouts cause an increased demand for energy, which can only be met adequately with at least some fuel in your system. When you are running on empty, your body may instead be forced to break down muscle for energy, thus leading to a decrease in performance and increased fatigue. For safety reasons and for best results, stick with low-intensity exercises such as walking or light jogging when working out on an empty stomach.

Also be aware that if your blood sugar is low from not having eaten recently, prolonged exercise can make you lightheaded or cause a drop in blood sugar levels which further decreases performance and increases the chance of injury. Therefore, it is important to ensure that your workout is manageable and not overly strenuous when training on an empty stomach. Finally, remember to hydrate both before and after your exercise session since dehydration can lead to headaches or worse side effects.


To conclude, whether or not to workout on an empty stomach will depend on your individual goals and circumstance. While some studies show that it can lead to greater fats loss in the long run by regulating insulin levels, others suggest that carbohydrates should be consumed before a workout for maximum performance output and improved muscle recovery. Ultimately, it’s important to experiment and see what works best for you. As long as you are fuelling your body with quality foods and staying adequately hydrated, there’s no wrong way to set up your nutrition around training sessions. Be mindful of how you feel before and after workouts, as well as over the course of several weeks – this will provide the best indication of which approach is working best for your body.

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