Regular exercise is an important part of a healthy lifestyle, as it helps us live longer. Getting the most from your workout routine depends on many factors. The timing of your meals and actual workouts matters too. You’ve probably come across people who claim exercising on an empty stomach is beneficial for them. Others never do that. What’s better? Is it safe to exercise on an empty stomach or you should always make sure to do it after your meals? This post has all the answers you need to know.
Is it Bad to Exercise on An Empty Stomach
Even though exercise plays a vital role in a healthy lifestyle, there’s still a lot we need to learn about it. Let’s say you decide to exercise on an empty stomach. The first question that comes to your mind is whether it’s safe or beneficial. Some studies show this approach may have some positive effects.
For example, a paper from the Proceedings of the Nutrition Society showed there is evidence that fasted exercise has the potential to improve training-induced skeletal muscle metabolic profile adaptations. It can also mitigate against the adverse impact of short-term excess intake of energy on glucose tolerance, compared to the fed state. That being said, further research is necessary. It is particularly important to carry out a study that focuses on the long-term effects of exercising on an empty stomach (1).
A study from the journal PLoS One found an exercise program performed on an empty stomach, after overnight fasting, increases the 24-hour oxidation of fat. This effect could be attributed to the circadian nature of the early morning hours or due to the nutritional state (2).
One review of current evidence on this subject suggested different fasting practices reduce fat and body weight, in trained and untrained participants alike. Also, fasting affects protein, glucose, and lipid metabolism and it is linked to hormonal responses. The review also showed studies regarding exercise treatment on empty stomach show conflicting results. Some studies revealed athletic performance decreased whereas other pieces of research showed no effect. These differences occur due to several reasons including fasting duration, experimental design variations, and characteristics of each subject. Scientists recommend athletes to perform low-intensity training when they want to exercise on an empty stomach (3). Walking is a good way to get more activity without overdoing it.
That being said, a study from the British Journal of Nutrition compared the effect of aerobic training performed in fasted versus fed states and made interesting findings. Compared to the fed state, there were significant increases in fat oxidation in subjects who exercised on empty stomach (4).
Based on the evidence mentioned above, exercise on an empty stomach is not exactly bad for you. It can improve fat oxidation, or even cholesterol levels and diabetes. But, it still doesn’t mean this approach is ideal, particularly if you have some chronic diseases.
Exercising on an empty stomach could decrease your stamina and impair energy levels. Plus, you also risk low blood sugar which is associated with nausea, lightheadedness, and shakiness. In some people, exercise on an empty stomach can affect brain function by making them less energized and thereby difficult to concentrate.
This can also affect your blood pressure. Therefore, the best thing to do is to consult a doctor who will provide medical advice on this subject, based on your health and goals, and heart disease risk.
Can You Lose Weight with Exercise on An Empty Stomach?
Advocates of exercising on an empty stomach claim this method can, actually, promote weight loss. Can it really? Current evidence on this subject shows mixed results.
One study recruited 20 young female volunteers all of whom reported they performed aerobic exercise a few times a week. The main goal of the study was to analyze changes in fat mass and fat-free mass after four weeks of volume-equated fasted and fed cardio training in subjects who followed a hypocaloric diet.
The results showed body composition changes linked to aerobic training combined with hypocaloric diet are similar regardless of whether subjects worked out before or after meals. Scientists concluded those who want to lose body fat and follow a hypocaloric diet can choose when to exercise based on their preferences (5).
In other words, exercising on an empty stomach wasn’t more effective than workout at a fed state among persons who reduced calorie intake.
Additionally, one study revealed morning exercise on an empty stomach could have a better influence on body fat reduction than post-prandial physical activity. Exercising in a fasting state can increase cortisol levels, however, and thereby negatively affect long-term weight loss (6).
On the other hand, some evidence reveals fasting before morning workouts can reduce 24-hour energy intake and increase fat oxidation during a training session. Exercising in the morning, on an empty stomach, could be effective for helping subjects maintain their weight (7). It’s useful to mention this piece of evidence was obtained from a study whose subjects were healthy young men. Subjects had a healthy weight. The full mechanism of action requires further research, but the study did show the subjects consumed more food at night on days when they ate breakfast.
It’s also useful to mention that the September 2021 issue of the European Journal of Nutrition published a study that showed planned fasted aerobic training can increase energy intake in the following afternoon or evening. This precipitates about a 10% increase in energy consumption during the following 24 hours. That being said, these increases didn’t completely translate to energy expenditure during the workout. In other words, exercise produced acute negative energy balance (8).
What we can conclude here is that it would be impossible to claim exercise on an empty stomach can or cannot promote weight loss. The theory is pretty convincing; during exercise we need energy and the body starts obtaining it from stored fat. This would allow us to burn more fat during the workout, but in some cases, it doesn’t work that way.
As seen above, some studies do show the health benefits whereas others reveal no such effect. Some studies also report the effects are not better than those of exercise in the fed state. More research on this subject is crucial.
Current studies had a small sample size and were focused on short-term results. We also need to bear in mind exercise on an empty stomach could prompt the body to use protein as a source of energy. This automatically decreases the concentration of protein in the body. Your body needs protein to repair muscles after a workout and for optimal fitness levels. At the same time, even if you start using fat for energy during exercise, it doesn’t really mean you’ll have a lower fat percentage in the body. Also, it doesn’t indicate you’re going to burn calories (9, 10, 11).
Should You Exercise on an Empty Stomach?
The answer to this question depends on your goal. First, it’s useful to remember exercising before eating can cause low blood sugar, which has uncomfortable symptoms. You may feel tired and notice it’s difficult to exercise as intensely as you do when exercising after eating. Even a small pre-workout snack can give you more energy to improve athletic performance in the gym.
Eating something before a good workout is particularly important for persons who are older than 55 years of age. Even more so if they tend to work out the first thing in the morning. Over the night, the body goes through physical adjustments that allow us to survive. One of these adjustments is that the body kind of breaks itself down to sustain blood sugar levels. Therefore, early morning exercise on an empty stomach only prolongs this “breakdown state”. Eventually, you may experience muscle loss.
Basically, exercise on an empty stomach may not be such a good idea for men and women who want to increase muscle mass. It’s also not suitable for older adults who want to preserve their muscle mass, as well (12).
Good news, if your main goal is to lose weight, exercise on an empty stomach could be beneficial to some extent. Don’t forget that further research is necessary.
For persons who aren’t athletes, eating something healthy before exercise could be the best option to get the most from its fat-burning potential (13). Your pre-exercise snack should include a combination of protein and carbs.
For example, you can have a spoonful of peanut butter and half a banana. The goal isn’t to eat too much, but to increase energy levels for a quality workout. Eating something before a workout is also beneficial if you need to take your medicine regularly.
Once you’re done with the exercise, you should drink water. Hydration is important. Wait for 60 to 90 minutes before you eat something after your workout.
What Are 10 Reasons to Exercise?
Reasons to work out regularly are numerous, but the top 10 perks of exercising include:
- Energy boost and better quality of life
- Burning more calories at rest
- Weight loss and improved overall appearance
- Stress management
- Reduced risk of illness
- Stronger focus
- Improved cardiovascular health and endurance
- Increased lean body mass
- Better flexibility
- Getting more sleep
What Are 10 Good Exercises?
An active man or woman has a multitude of exercises and activities at their disposal. Ideally, you should opt for workouts or activities that you really like or enjoy. That way you’re more likely to stick to them, especially if you were sedentary before. But some exercises should be a part of everyone’s routine. Top 10 exercises include:
- Burpees – whole-body exercise, improves cardiovascular endurance and muscle strength
- Dumbbell rows – great for back and targeting multiple muscle groups
- Glute bridge – activates posterior chain
- Lunges – promote functional movement, increase strength in glutes and legs
- Plank – targets abdominal muscles and the whole body, stabilizes core without straining your back
- Pushups – activates multiple muscle groups, good for strong muscles and strong bones
- Side planks – strengthen core
- Single-leg deadlifts – improves balance, stability, and leg strength
- Squats – increase core and lower body strength, improves flexibility in hips and lower back
- Standing overhead dumbbell presses – a type of compound exercise that targets several muscle groups (shoulders, upper back, and core)
Get the most from your exercise routine by challenging the body. Increase the number of sets and reps when it becomes easy or effortless to perform the current amount. Also, make sure to combine cardio and strength training by lifting weights.
Is it Good to Exercise When Fasting?
While nothing bad will happen if you exercise when fasting, it may not be the best idea for the person who wants to increase muscle mass. Exercise at a fasting state could urge the body to burn protein as fuel and thereby break down muscle. Additionally, you’re more likely to deplete energy levels this way.
What is Considered an Empty Stomach?
The term empty stomach refers to one hour before eating or two hours after the last meal. Although food generally leaves the stomach within two to four hours, the exact time may depend on several factors. These include relaxation of the upper portion of the stomach, digestion, and emptying (14,15).
Once food leaves the stomach, it moves through the small and large intestines. So, how much time does it take to leave our body altogether? Between two and five days are necessary for food to leave the entire gastrointestinal tract.
Is an Empty Stomach Healthy?
An empty stomach may not lead to serious side effects or noticeable problems when it happens occasionally. But if your empty stomach is a common occurrence, you may experience problems ranging from hunger pangs to low energy, breaking down protein and hyaluronic acid, among other adverse reactions.
Choose your workout time wisely. Your stomach is usually empty before bedtime, but exercising at that time may not be a good idea if you want to fall asleep easily.
How Long Does it Take to Empty Your Stomach?
Generally speaking, it takes up to five days in total to empty the entire GI tract. On average, food takes up to four hours to leave your stomach. Several factors influence the movement of food, which is why it may leave the stomach faster or slower in some people.
What Should Be Eaten on an Empty Stomach?
While you do have the freedom to eat anything you want, some foods are a better choice to eat on an empty stomach than others. So, you may want to eat:
- Soaked almonds
- Raisins
- Papaya
- Watermelon
- Chia seeds
- Porridge
- Nuts
- Buckwheat
- Eggs
- Blueberries
- Whole grain bread with no yeast
- Warm water and honey (not food per se, but beneficial)
Foods to avoid on an empty stomach include:
- Tomatoes – contain high levels of tannic acid and thereby increases stomach acid levels
- Processed sugar – overloads the liver
- Bananas – may cause an imbalance of magnesium and potassium in the body, if eaten on an empty stomach
- Yogurt and other fermented milk products – hydrochloric acid that may form in the stomach can kill the bacteria from lactic acid
- Green vegetables such as cucumbers – abundant in amino acids which may cause heartburn, abdominal pain, and flatulence when consumed on an empty stomach
Conclusion
Exercise on an empty stomach is not harmful, but may also not be the best choice. In some cases, this approach could have more cons than pros. However, the actual answer may vary from one person to another. You may benefit more from having a small, healthy snack before your workout. Many people who want to avoid weight gain decide to exercise on an empty stomach, but you need to take into account your needs and choose the best option.
References:
- https://pubmed.ncbi.nlm.nih.gov/30334499/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5503250/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6983467/
- https://pubmed.ncbi.nlm.nih.gov/27609363/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242477/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4500013/
- https://www.hindawi.com/journals/jnme/2016/1984198/
- https://pubmed.ncbi.nlm.nih.gov/33620552/
- https://www.healthline.com/health/fitness-exercise/working-out-on-an-empty-stomach#weight-loss
- https://www.eufic.org/en/whats-in-food/article/what-are-proteins-and-what-is-their-function-in-the-body
- https://www.medicinenet.com/is_it_ok_to_work_out_on_an_empty_stomach/article.htm
- https://time.com/4986422/working-out-fasted-cardio-benefits/
- https://www.webmd.com/fitness-exercise/features/can-i-work-out-on-an-empty-stomach#1
- https://www.healthline.com/health/how-long-does-it-take-for-your-stomach-to-empty#time-in-stomach
- https://www.nytimes.com/2018/09/28/well/live/drug-medication-empty-stomach-prescription.html
