Intermittent fasting is praised by most for aiding weight loss and disease prevention. Fasting after a workout has demonstrated that protein synthesis and fat burn increase with time following a workout. This indicates that you will benefit more from your workouts if you wait at least a couple hours before eating or breaking your fast.
While this might be an easier case for some, it might be difficult for you to remain fasting after an exercise because your metabolism is revved up and energized, needing you to refuel your body after workout which could lead you to feel hungry.
Let’s explore how fasting after workout affects you and learn how important it is to eat after your workout.
What Is Intermittent Fasting?
Intermittent fasting, often known as time-restricted feeding, is an eating strategy in which you alternate between fasting and eating on a set schedule. When you eat is more important than what you consume. Some people fast for religious reasons, while others fast for weight loss, health reasons, or the ease of eating less frequently.
In intermittent fasting, you only eat at some times and fast at others. The most common method of practicing intermittent fasting protocols is to fast for a set number of few hours each day. Another option is to fast totally on certain days of the week.
Different Types of Intermittent Fasting
Intermittent fasting can be done in a variety of different ways. The amount of short days and calorie limitations varies between the strategies, and varied trend preferences will exist. Here are the different approaches or time restrictions in intermittent fasting:
- Fast for 12 hours a day
This diet has straightforward guidelines. You must choose and follow a 12-hour fasting window each day. The only thing you can consume is liquid and they have to be calorie free such as water and tea.
Some researchers1 claim that fasting for 10 to 16 hours can induce the body to use its fat burning reserves as fuel, releasing ketones into the bloodstream. This ought to promote weight loss.
For novices, this intermittent fasting protocol is a decent choice. This is because the fasting window is so brief, you can have the same quantity of calories every day, and most of the fasting can happen while you sleep.
The most straightforward approach to completing the 12-hour fast is to include the time spent sleeping. For instance, you could decide to abstain from food between 7 p.m. and 7 a.m. You would have to finish eating before seven o’clock and wait till 7 a.m. to have breakfast, spending most of your 12 hours asleep.
- Fasting for 16 hours
The 16:8 approach, also known as the Leangains diet, involves fasting for 16 hours per day, followed by an 8-hour window for eating.
Men fast for 16 hours daily, while women fast for 14 on the 16:8 diet. If you’ve tried the 12-hour fast before and didn’t experience any benefits, this sort of intermittent fasting is beneficial.
During this fast, dinner is typically finished by 8 o’clock. Then skip breakfast the following day and wait until noon to eat again.
A study2 on mice found that limiting the feeding window to 8 hours protected them from obesity, inflammation, diabetes, and liver disease, even when they ate the same number of calories as mice that ate whenever they wished.
- Fasting for 2 days a week
The 5:2 diet involves eating average-sized portions of wholesome food on five days and consuming fewer calories on the other two days.
Men typically ingest 600 calories and women 500 calories each of the two fasting days.
Typically, you set aside specific days of the week for fasting. For instance, you might eat regularly on the other days and fast on Monday and Thursday. Between each fasting day, there should be at least one non-fasting day.
- Alternate-day Fasting
The alternate-day fasting regimen, which calls for fasting every other day, comes in various forms.
Alternate-day fasting can entail avoiding all solid foods on fasting days for some persons while allowing up to 500 calories for others. People frequently decide to eat as much as they want on feeding days.
One study3 reports that alternate-day fasting is effective for weight loss and heart health in healthy habits and overweight adults. The researchers found that the 32 participants lost an average of 5.2 kilograms (kg), or just over 11 pounds (lb), over 12 weeks.
Alternate-day fasting is a rigorous kind of intermittent fasting. Hence it might not be appropriate if you are new to fasting or if you have particular medical concerns. Long-term maintenance of this kind of fasting could also be challenging.
- A weekly 24-hour fast
The Eat-Stop-Eat diet entails going without meals for 24 hours on one or two days a week. Many people observe a fast from lunch to lunch or breakfast.
You will still follow consuming calorie-free beverages, including water, tea, and others while fasting. However, to help prolong your fast, you can include fluids such as bone broth.
After your 24 hour fast, you should resume your regular eating habits. This type of eating reduces your overall caloric intake without limiting the kinds of first meal you consume.
A 24-hour fast can be difficult and result in headaches, weariness, or anger. Many people discover that these effects gradually become less severe when their bodies become used to this new eating pattern.
- Meal Skipping
Beginners may benefit from this flexible approach to intermittent fasting regimen. It occasionally entails skipping meals.
You can choose which meals to miss depending on how hungry you are or how much time you have. However, it’s crucial to eat wholesome foods at every first meal.
Meal timing is most successful when you pay attention to and act on your hunger cues. In essence, if you practice this form of intermittent fasting you will eat only when you are starving and forgo meals otherwise.
This may feel more natural for some people than other fasting techniques.
- The Warrior Diet
A relatively extreme example of intermittent fasting is the Warrior Diet.
The Warrior Diet entails fasting for 20 hours, only a few servings of raw fruit and vegetables are consumed, and then having one massive meal at night. Typically, the eating window lasts only four hours.
Those who have tried other types of intermittent fasting may benefit from this fasting the most.
The Warrior Diet’s proponents assert that since humans are naturally nocturnal, eating at night enables the body to absorb nutrients in harmony with its circadian rhythms.
You should consume many vegetables, proteins, and carbohydrates (such as dairy products) during the 4-hour eating phase. You also ought to have plenty of non-calorie fluidsas well.
Fasted Workouts And Fasting After Workout
A fasted workout is performed while fasting (at least four to six hours after eating). Fasting allows your body to digest and assimilate much of what you ate at your last meal. That implies your body’s preferred fuel will shift from glucose to fat.
Insulin sensitivity or insulin resistance and glucagon levels fluctuate in response to the quantity of glucose in your blood and liver. When your blood glucose levels are high, your body turns to glucose for fuel.
Glucose is derived from all macronutrients but primarily from carbohydrates. When blood glucose levels fall, your body begins to burn fat to protect the glucose stored in muscle and the liver—this aids in maintaining an optimal blood glucose level.
In some cases, others choose to break their fast after a workout and very rarely do they continue fasting after. However, fasting after a workout has been shown to have its benefits.
Fasting is known to significantly increase Human growth hormone (hGH) secretion, which plays a role in your metabolism and keeps your blood sugar (glucose) levels within a healthy range. Intense exercise also triggers a rise in hGH. Combining the two may maximize your body’s hGH release.
However, fasting after every workout is not ideal and further studies will still need to be done to support the benefits of fasting after a workout. Working out while fasting and breaking your fast after is much more preferable.
The Benefits Of Fasted Workouts
Fasting improves insulin sensitivity, and insulin levels enhance growth hormone synthesis. Both can increase fat loss, crediting the hypothesis that fasting exercise leads to more fat loss.
Having an insulin response when fasting before training is a tactic to boost fat burning in the hopes of utilizing some stored fat. Another study on just 12 men discovered that skipping breakfast before a workout reduced overall calorie consumption for the day—fat oxidation three hours after exercise was actually higher in those who ate before, and feelings of hunger after a workout were similarly lower in those who ate before4.
The Cons Of Fasted Workouts
The high intensity workout influences whether your body burns fat or glucose for energy. Heavy lifting or quick running will burn stored muscle glucose (glycogen) more than fat, whether done on an empty stomach or not5.
You may burn some extra fat during a fasted exercise session, but it is unlikely to be enough to burn a lot of stored fat when all factors are considered6.
Fasting After Workout: What You Need To Know
Food As Fuel
Eating and exercise go hand in hand and it’s important to keep an eye on your nutrition. How you fuel and refuel before and after exercise helps make sure you’re taking in enough energy to fully benefit from your workouts. Fueling your body is especially crucial even while fasting.
- Cardio and Intermittent Fasting – your body uses fat and sugar to fuel exercise. Depleted muscle and liver glycogen stores occur when you fast. If you are doing cardio in a fasted state, avoid extending the fast post-workout, and opt to refuel after you finish.
- Lifting Weights and Fasting – similar to cardio, you go into a fat burning state when doing weight lifting. Lifting puts stress on your body to warrant an immediate nourishment.
What Happens If You Don’t Eat After a Workout?
You’ve probably heard something about what not eating after a workout can do to your body, but it’s worth reiterating.
You break down building muscle protein synthesis throughout a workout, causing microscopic micro-tears in the tissue. That breakdown process allows you to gain muscle mass and help them grow bigger and stronger, but only if you properly refuel with nutrients like protein intake, which helps to heal that damage.
Failure to fuel after an exercise might cause your body to enter a catabolic state, where it will break down and build muscle mass and reduce your metabolism, which is the reverse of what you want.
You’ll also need to consume carbohydrates if your workout includes cardio. To fuel your activities, your body uses glycogen stores, or stored glucose, as energy, which it obtains through converting carbohydrates.
Rebuilding the supply gives you the power to recover correctly from your workout and continue with your day efficiently.
Does Fasted Cardio Lead To Greater Weight Loss?
Whenever fasted cardio comes to mind, early morning workouts are often the most ideal. A fasted cardio is good for burning fat.
This is largely due to the idea that if you fast overnight and work out first thing, insulin is low (when fasting) and should allow more fat to be burned. Your body is also depleted of glucose — its primary energy source — and will instead use stored fat for fuel.
But this isn’t to say that fasted cardio is better when compared to doing cardio after eating a meal.
A large study published in the International Society of Sports Nutrition journal in 2014 looked at changes in body composition following four weeks of fed cardio versus fasted cardio during a hypo caloric diet7.
It was found that body composition changes were similar in the fed and fasted cardio group and ultimately, one can’t actually say that one is better than the other and choosing to do a fasted workout can entirely be based on your preference.
Should You Eat Even If You’re Not Hungry?
Whether you’re hungry or not, eating within two hours of exercise is critical. Yes, that includes those of you who are practicing intermittent fasting.
That doesn’t mean you have to break your fast at the same time every day, though you should if you don’t plan to eat for more than two hours after exercise. If you want to keep to your fasting schedule, you’ll need to plan your eating window and workouts so that you can refuel within that two-hour window.
If you are not hungry after a workout, it is nevertheless recommended that you consume some protein and carbohydrates.
What Is Muscle Mass?
Muscle mass refers to the total quantity of muscle mass in your body composition, which includes skeletal muscle loss, smooth muscle loss, and cardiac muscle loss. It, along with fat and bone mass, can be measured as part of your overall body composition.
What Helps Muscle Protein Synthesis?
The process in which cells make proteins is called protein synthesis. Protein consumption before and after exercise is recommended because it plays an important role in repairing and rebuilding your muscles after exercise.
To increase protein synthesis, ten grams of necessary amino acids or twenty-five grams of complete protein are adequate. The type, time, and amount of protein consumed all have a role in gaining muscle mass.
What Happens When You Don’t Eat Enough After Working Out?
If you do regular exercise, you should know what happens when you don’t eat enough after working out. While fasted workouts are acceptable since nothing harmful will occur, it can lead to problems.
Some of these include:
- Low Energy
- Poor Muscle Recovery
- Poor Weight Management
- Low electrolyte levels
Most dietitians recommend eating within 30 minutes of finishing an exercise. After burning up all available energy, your body requires refueling, specifically with carbs and protein, for energy and to repair the microdamage that exercise does to your muscles.
Foods To Eat After A Workout
It’s ideal if you can have a full meal packed with protein, carbs, and veggies within two hours of exercise, but that may not always be possible.
If you know you won’t be able to sit down for a few minutes or don’t feel like eating a full meal, consume a piece of fruit, such as a banana, on the side or mix it into the smoothie.
Here’s why these type of food are important and a short list of food that are packed with the ideal before or after workout meal:
There’s no need to push the extra protein, but you have to eat protein for your body composition if you’re going directly from the gym to a meal; make sure you have healthy meals on your plate, along with carbs and vegetables.
Consuming an adequate amount of protein ensures that your body has the amino acids it needs to repair and rebuild these proteins. It also gives you the building blocks required to build new muscle tissue.
Carbs are also essential for recovery. It’s especially crucial to replace your glycogen stores after intense cardio activities.
Your body’s glycogen stores are used as fuel during exercise, and consuming carbs after your workout helps replenish them.
- Fruits with a low glycemic index (GI), such as apples, pears, berries, or cherries (GI measures how much a particular food raises your blood sugar control group.)
- Sweet Potatoes
- Quinoa and other grains
- Whole Grain Bread
And, while post-workout nourishment is crucial, keep in mind that it is only a percentage of your overall regular diet. A pre-or post-workout meal will benefit you less than routinely eating nutritious and balanced meals.
This is especially vital if you have specific goals like decreasing weight training or increasing muscle. Not just what you eat after your workout but all your meals and snacks should be planned with those goals in mind.
The Bottom Line
Fasted workouts are a suitable option to try if you’re struggling to see changes in your body composition or lose those last few stubborn pounds. It can maximize the benefits of exercise and intermittent fasting by combining the two.
In the case of fasting after a workout, unless you do a heavy weight session or endurance cardio, you can benefit from it provided that you replenish within a few hours from your workout. Ultimately, post exercise meals are ideal and it’s preferable that you consume protein and carbs for better recovery.
2 Hatori M, Vollmers C, Zarrinpar A, DiTacchio L, Bushong EA, Gill S, Leblanc M, Chaix A, Joens M, Fitzpatrick JA, Ellisman MH, Panda S. Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metab. 2012 Jun 6;15(6):848-60. doi: 10.1016/j.cmet.2012.04.019. Epub 2012 May 17. PMID: 22608008; PMCID: PMC3491655.
3 Varady KA, Bhutani S, Klempel MC, Kroeger CM, Trepanowski JF, Haus JM, Hoddy KK, Calvo Y. Alternate day fasting for weight loss in average weight and overweight subjects: a randomized controlled trial. Nutr J. 2013 Nov 12;12(1):146. doi: 10.1186/1475-2891-12-146. PMID: 24215592; PMCID: PMC3833266.
4 Robert M Edinburgh, Aaron Hengist, Harry A Smith, Rebecca L Travers, James A Betts, Dylan Thompson, Jean-Philippe Walhin, Gareth A Wallis, D Lee Hamilton, Emma J Stevenson, Kevin D Tipton, Javier T Gonzalez, Skipping Breakfast Before Exercise Creates a More Negative 24-hour Energy Balance: A Randomized Controlled Trial in Healthy Physically Active Young Men, The Journal of Nutrition, Volume 149, Issue 8, August 2019, Pages 1326–1334, https://doi.org/10.1093/jn/nxz018
5 Joram D. Mul, Kristin I. Stanford, Michael F. Hirshman, Laurie J. Goodyear, Chapter Two – Exercise and Regulation of Carbohydrate Metabolism, Editor(s): Claude Bouchard, Progress in Molecular Biology and Translational Science, Academic Press, Volume 135, 2015, Pages 17-37, ISSN 1877-1173, ISBN 9780128039915.