Fasted cardio refers to performing cardiovascular exercise on an empty stomach, typically first thing in the morning before eating breakfast. The idea behind fasted cardio is that in the absence of recently consumed carbohydrates, the body is more likely to use stored fat for energy during the workout.
While it’s true that after fasting, your body uses stored carbs and fat for energy, leading many to believe it results in more fat loss, the reality is a bit different. So, do you really need to do fasted cardio for fat loss? Let’s discuss this in detail.
What Do The Studies Say?
In 2014, a major study published in the journal of the International Society of Sports Nutrition investigated how body composition changes after four weeks of doing cardio either on an empty stomach (fasted cardio) or after eating (fed cardio) while on a calorie-restricted diet. The study found that, as long as the total calories consumed were the same, the changes in body composition were similar for both groups.
Two years later, the British Journal of Nutrition published a comprehensive review and analysis of various studies on fasted and fed cardio. This research focused on how these types of exercise affect fat and carbohydrate metabolism, not just fat loss. It was concluded that performing aerobic exercises in the fasted state induces higher fat oxidation.
Fasted cardio has also been shown to be effective in improving whole-body glucose tolerance and insulin sensitivity, important for weight loss and overall health.
So, Is Fasted Cardio Worth It For Fat Loss?
Although research suggests that fasted cardio can lead to higher levels of fat oxidation during exercise, this is not the same as fat loss. If your goal is to maximize fat burning during your workouts and improve insulin sensitivity, fasted cardio may be a good option for you.
However, if fat loss is your goal, the most important aspect here is burning more calories than you consume. Creating a calorie deficit along with combining both cardiovascular and strength training exercises will help you to preserve muscle mass, improve performance, and achieve fat loss faster and healthier.
Regardless of whether you choose fasted or fed cardio, and even for your strength training exercises, post-workout nutrition is crucial. Your body needs to repair its muscle tissue and replenish glycogen stores after exercise. Consuming a balanced meal with adequate carbohydrates and protein can help with your post-workout recovery and enhance your results.
Is Fasted Cardio Safe?
Mostly, yes. If you’re in good health overall, it may be fine and safe for you to add short or moderate-length steady-state fasted cardio workouts to your routine.
However, if you’re planning on working out for any extended period of time or doing a high-intensity workout, doing fasted cardio can be risky, as it might lead to low blood sugar or dehydration, causing potential side effects like feeling lightheaded, dizziness, shaking, or even passing out.
It is also suggested to avoid fasted cardio if you are pregnant or have any medical condition sensitive to low blood sugar or blood pressure. Additionally, if you’re a complete beginner, it’s best to avoid fasted cardio — understanding your body well should be the very first step on your exercise journey.
Conclusion
Ultimately, the key to effective fat loss is consistency, calorie deficit with a balanced diet, and a comprehensive exercise program that includes both cardiovascular and strength training exercises. Fasted cardio may be helpful for some people, particularly those who find it convenient and have specific goals, like shedding those last few pounds.
As with any fitness strategy, it’s important to consider personal health conditions and consult with a healthcare or fitness professional before incorporating fasted cardio into your routine.
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References:
Schoenfeld, Brad Jon, et al. “Body composition changes associated with fasted versus non-fasted aerobic exercise.” Journal of the International Society of Sports Nutrition 11 (2014): 1-7.
Vieira, Alexandra Ferreira, et al. “Effects of aerobic exercise performed in fasted v. fed state on fat and carbohydrate metabolism in adults: a systematic review and meta-analysis.” British Journal of Nutrition 116.7 (2016): 1153-1164.
Van Proeyen, Karen, et al. “Training in the fasted state improves glucose tolerance during fat‐rich diet.” The Journal of physiology 588.21 (2010): 4289-4302.
