Regular exercise is one of the best things you can do for your physical and mental health and well-being. This has been shown time and time again in research.[1,2,3,4] Vigorous exercise has also been shown to lower risk of premature death and boost longevity.[1,3]
The bare minimum amount of exercise to support overall health is 150 to 300 minutes per week of moderate exercise, but the life-prolonging benefits really start to show when individuals work out between 300 to 599 minutes each week.[1]
In fact, people who train 2-4x more than the minimum recommended amount have a 26-31% lower all-cause mortality and a 28-38% lower risk of cardiovascular disease mortality.[1]
While the evidence is clear that you should exercise multiple times per week using a mixture of resistance training and cardiovascular training (“cardio”), what’s less clear are the proper ways to fuel your body for those workouts.
Go down the search engine or social media rabbit hole deep enough and you’ll find all sorts of suggestions for the “right” way to for a workout. Oftentimes, you’ll get conflicting information.
Some will say you should work out fasted. Others say you should always eat something before you train.
We’re here to separate fact from fiction and provide insights to help you figure out what works best for your body and hopefully help you answer the question of “is working out on an empty stomach good for you?”
Let’s get started.
The Advertised Benefits of Fasted Workouts
Technically speaking, fasted workouts (i.e. working out in a fasted state) maximizes fat burning, meaning your body is burning stored body fat for energy. Based on this rationale, all of your workouts should be fasted if you’re interested in weight loss or body recomposition.
It’s also true that when you workout within a few hours after eating a meal, you are primarily burning the calories from the food you recently ate for energy, thus not burning fat.
Essentially, why would you want to burn the calories you just ate instead of burning the extra fat on your body.
This is what many ardent proponents of fasted training profess to their followers.
However…
The Truth About Fasted Workouts
While the theoretical mechanism that is promoted on the internet makes sense, it fails to understand just how adept the human body is.
You see, when you spend large portions of the day in a fasted state (in which you’re burning fat for energy), the body compensates later on by burning more carbohydrates to fulfill its energy requirements.
Remember, our bodies are equipped with two primary functions -- carrying on the species (i.e. procreation) and survival. It adapts to whatever we throw at it (within reason, of course).
A critical point to remember is that fat loss is ultimately governed by fat consumed - fat burned.
We shouldn’t care about how much fat burning (“fat oxidation” if we’re being technical) occurs during a given workout. We should focus on how much fat is burned over the course of a day, a week, a month, etc. That is what truly governs meaningful body fat reduction.
Having some carbohydrates before a workout, even if it’s cardio, can help you to train harder, push farther, and ultimately burn more calories, which can help you achieve the calorie deficit needed to burn excess body fat.
Sure, you may burn more carbohydrates for energy during your workout, but the research is clear -- so long as you are in a calorie deficit at the end of the day, week, etc. you will lose body fat (provided you consume adequate protein and engage in resistance training to preserve lean muscle).[5]
Additional studies also indicate that high-intensity exercise training (anaerobic in nature) provides a superior abdominal fat loss effect than low- and moderate-intensity exercise training.[6] High-intensity exercise, such as HIIT or interval training, primarily relies on carbohydrate to fuel your muscles, not carbohydrates. Yet it’s shown to be just as effective for fat loss and calorie burning despite taking up less time.
The Bottom Line
Fasted workouts can work.
Eating before your workouts can work.
It really depends on your schedule, and how you feel (fasted or fed) during your cardio or resistance training workouts.
Do you feel energetic? Do you feel lethargic during your workouts?
These are the questions that you need to consider when deciding which meal planning strategy to adopt for your workouts.
So long as your total daily energy intake is LESS than your total daily energy expenditure (TDEE), you will lose weight whether your cardio is low-intensity, high-intensity, fasted or fed (or some combination of those).
Regardless of which type of cardio you choose to perform, keep in mind that resistance training and adequate protein intake are essential to maintaining lean muscle while stripping away body fat.
A good rule of thumb is to consume one gram of protein per pound of bodyweight. For example, if you weigh 150 pounds, then you will want to consume 150 grams of protein. Ideally this would be evenly distributed across the day and come from high-quality protein sources, including lean beef, dairy, eggs, poultry, seafood, and fatty fish. Protein powder, such as whey protein, egg white protein, or vegan protein powder, is also an effective, affordable, and delicious way to hit your protein goals.
Supplementing with protein powder has also been shown to help reduce appetite and support weight loss/body recomposition.
In addition to protein, caffeine has been shown to enhance fat burning, increase energy expenditure during exercise, and reduce appetite.[7] This is why caffeine is the backbone of our best-selling weight loss supplements, Make Her Lean Max and Pro Ripped Max.
Last, but not least, if you have questions about how many calories to eat for weight loss, what are effective workouts for reaching your goals, or which supplements are best for you, we’re here for you!
When you sign up for our Transformation Challenge and download our FREE 1UP Fitness App, you’ll get access to our private Facebook group where you can ask questions, interact with like-minded fitness enthusiasts, and receive advice from experienced coaches.
References
- Lee, D. H., Rezende, L. F. M., Joh, H.-K., Keum, N., Ferrari, G., Rey-Lopez, J. P., Rimm, E. B., Tabung, F. K., & Giovannucci, E. L. (2022). Long-Term Leisure-Time Physical Activity Intensity and All-Cause and Cause-Specific Mortality: A Prospective Cohort of US Adults. Circulation, 146(7), 523–534.https://doi.org/10.1161/CIRCULATIONAHA.121.058162
- Wang Y, Ashokan K. Physical Exercise: An Overview of Benefits From Psychological Level to Genetics and Beyond. Front Physiol. 2021 Aug 12;12:731858. doi: 10.3389/fphys.2021.731858. PMID: 34456756; PMCID: PMC8397487.
- Reimers CD, Knapp G, Reimers AK. Does physical activity increase life expectancy? A review of the literature. J Aging Res. 2012;2012:243958. doi: 10.1155/2012/243958. Epub 2012 Jul 1. PMID: 22811911; PMCID: PMC3395188.
- Mahindru A, Patil P, Agrawal V. Role of Physical Activity on Mental Health and Well-Being: A Review. Cureus. 2023 Jan 7;15(1):e33475. doi: 10.7759/cureus.33475. PMID: 36756008; PMCID: PMC9902068.
- Schoenfeld BJ, Aragon AA, Wilborn CD, Krieger JW, Sonmez GT. Body composition changes associated with fasted versus non-fasted aerobic exercise. J Int Soc Sports Nutr. 2014 Nov 18;11(1):54. doi: 10.1186/s12970-014-0054-7. PMID: 25429252; PMCID: PMC4242477.
- Harris MB, Kuo CH. Scientific Challenges on Theory of Fat Burning by Exercise. Front Physiol. 2021 Jul 6;12:685166. doi: 10.3389/fphys.2021.685166. PMID: 34295263; PMCID: PMC8290478.
- Tabrizi R, Saneei P, Lankarani KB, Akbari M, Kolahdooz F, Esmaillzadeh A, Nadi-Ravandi S, Mazoochi M, Asemi Z. The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr. 2019;59(16):2688-2696. doi: 10.1080/10408398.2018.1507996. Epub 2018 Oct 18. PMID: 30335479.
