Lifting weights while fasting may seem counterintuitive, but is safe and can benefit your health. If your primary focus is to lose weight (body fat) while maintaining your body composition, lifting weights could help you focus on building or gaining muscle while avoiding muscle loss.
Many questions and arguments come with lifting weights while fasting. The biggest question is whether lifting weights is good because your body will need to use energy. This is a crucial question that can impact you if you are unaware of how training affects your body when fasting.
Contrary to belief, intermittent fasting does not deplete your muscles if you lift weights. In fact, according to research, resistance exercise along with intermittent fasting helps you maintain your muscle mass1,2.
Intermittent Fasting And Exercise
Intermittent fasting (IF) is an eating plan which involves alternating between times of eating and fasting. When you eat is more important than what you consume.
Intermittent fasting has some benefits, including maintaining lean muscle mass, lowering the risk of diabetes, reducing inflammation, and more3,4,5.
Your body needs nutrition to move, function, and grow. Abstaining from food presents the greatest difficulty for fasting and exercise. Energy, one of the fundamental macronutrients that make up everything you consume, is the fuel that comes from food and is most readily obtained from carbs.
But if you stop using food as a fuel source and reduce your intake, you might not have enough energy for your next workout. Because of this, you might think that intermittent fasting and exercise are incompatible and will not work hand in hand, right?
Not if you approach it correctly.
In intermittent fasting, you schedule your meals according to the time of day, regularly eating during some hours (or days of the week) and fasting during others.
When following a program like this, it’s essential to strategically plan your exercise sessions around when you’re fuelled or fasting to maximize fat loss and muscle building.
Potential Benefits Of Fasted Weight Training
Fasting results in a decrease in insulin. When your insulin levels are low during your fasted state, then your body uses body fat stores as the primary source of energy.
You can attain some remarkable benefits when your insulin levels are low, and together with a fasted training, you are able to achieve the following:
1. Boost Muscle Development
According to studies, a post-workout meal has a more significant anabolic effect after fasted weight training than after-fed training.
As a result, fast training can help your body recover faster from an intense workout and regain muscle mass more quickly6.
Another study revealed that fasting enhanced growth hormones by 1300% and 2000% in males and women, respectively. Growth hormones protect lean muscle tissue and help to balance metabolism7.
2. Increased Blood Flow To Your Abdomen
Studies have shown that training while fasting boosts blood flow to your abdomen8.
You can burn belly fat more quickly by increasing blood flow to your abdomen.
Blood flow is one of the reasons why losing fat in the lower abdomen is typically one of the most challenging areas to achieve.
This is not targeted fat loss. A fasted exercise encourages your body to burn extra fat from challenging areas naturally.
3. Increase VO2 Max And Peak Power
Although VO2 max is essential for endurance athletes, it can also be used if you are a gym-goer.
VO2 refers to your body’s capacity to utilize oxygen.
Regarding weightlifting, fasting weight training might enhance lifting output throughout a workout.
According to studies, people with higher VO2 max levels during exercise burn more fat9.
4. Burn Fat More Quickly
When you’re fasting and glucose isn’t available, your body turns to fat for energy.
Your body needs the energy to perform when you work out. Since glucose is simpler to convert into energy, it prefers glucose (from meals, primarily carbs).
According to studies, fasted exercise enhances lipolysis and fat oxidation rates, helping you burn fat more quickly10.
According to Northumbria University research, exercising first thing in the morning on an empty stomach can increase body fat burning by up to 20%11.
5. An Increase In Insulin Sensitivity
There are times when you are consuming more calories than your body needs.
Your body grows increasingly resistant to insulin if you continue doing this over an extended period of time (the hormone responsible for delivering nutrients where they need to go).
Your body adapts and becomes more sensitive to the restricted amounts of insulin due to consistent fasted training, which causes your body to produce insulin less frequently.
Your body can convert energy, burn fat, and increase blood flow more easily as a result of this improvement in insulin sensitivity12.
Negative Side Effects Of Lifting Weights While Fasting
Like any other type of activity, fasted training has possible side effects. This is why you need to seek the advice of a medical professional before starting fasted training.
You need to be aware of the possible difficulties and side effects such as:
- You Will Feel Weaker at First
When you initially start fasted training, you may feel sluggish if your body is accustomed to using carbohydrates for energy. Your body will become more adept at burning fat for energy once it has adapted. It will learn to use fuel more effectively.
Therefore, refrain from trying a fasted workout in preparation for your upcoming major weight lifting activity. You will need time to adjust to it.
- Rapid Training Can Increase Muscle Degeneration
According to research, fasted exercise can raise muscle breakdown rates, making it more difficult for your body to heal and become stronger13.
A study also shows that a shorter recovery time and improved nutritional absorption are two additional benefits of fasting exercise6.
Cardio vs Strength Training During Intermittent Fasting
In a study published in the Journal of Nutrition and Metabolism, participants who exercised on an empty stomach broke down more fat during cardio13.
According to some research, working out while fasting can speed up the body’s fat-breakdown process and promote weight loss. However, this depends on the exercise and your skill level14.
Intermittent fasting may help you get lean if your goal is to lift weights in order to trim down and look fit.
Fasted exercise may aid in fat loss, according to some data. However, doing so can reduce performance, cause loss of some muscle mass, and eat more after the activity15.
Lifting weights on an empty stomach won’t always result in muscle loss as long as you can quickly replenish your energy stores with a combination of protein and carbohydrates.
As per research, the window time is suggested to vary according to different factors, such as training level16.
Lifting Weights While Fasting: How To Do Fasted Workout Properly?
By limiting the time you can eat, you effectively limit the number of calories you intake, making intermittent fasting an effective strategy for weight loss. To complement this, you can exercise to make you more fit and tone your body.
However, though exercise is acceptable during a fasting, lifting weights while fasting is not suggested. It’s usually best if you weight lift during your eating windows or on days when you can eat normally.
That said, if you’re going to weight lift or even just any exercise while fasting, start with these simple guidelines to get started:
- Start Fasted Weight Training In The Morning.
This makes it quite simple if you exercise in the morning. Don’t eat breakfast; get up and start working out on an empty stomach.
If you want to do evening workouts, eat dinner afterward. Additionally, it will increase your anabolic reaction and assist your body in digesting the meal’s nutrients6.
You can lift an hour before you break your fast. You can then consume high-protein, high-carb post-workout meals to increase muscle building.
If you are too hungry to lift, lift during your eating window. You can adjust your eating window to eat immediately following your workout.
- Take BCAAs Before Working Out.
While you work out in the gym, your body breaks down muscles. It has been demonstrated that BCAAs reduce muscle breakdown, making it simpler for you to burn fat while intermittent fasting and doing fasted workouts17.
To maximize lean muscle growth, take 3-5 grams of BCAAs before your fasting workout18.
- Make Your Workouts Slow And Low.
If you’re going to exercise while you’re fasting, choose a low-intensity activity. This is crucial for prolonged fasts, including those lasting 24 hours or low-calorie days in the 5:2 diet.
Consider low-intensity steady-state aerobic exercises like walking, jogging, or riding a bike. This is because simpler exercises will encourage your body to burn fat. If you’re going to lift weights, go for lighter ones with which you can perform more reps.
High-intensity workout is not advised during intermittent fasting because these intensive workouts burn glycogen stores for fuel. Therefore, you might experience weariness and soreness following your workout.
- Pay Attention To Your Macros.
The International Society of Sports Nutrition advises aiming for a healthy source of protein and carbohydrates unless your goal is to maintain ketosis, in which case you should continue eating low carbs19.
Eating a balance of protein and carbohydrates before or after an exercise is crucial in supporting muscle gain. To exercise while fasting, try to do it before breaking your fast or during the meal period.
Depending on your personal goals and body weight, portions may change. An example of a healthy meal with good protein and carbs sources include chicken and rice, eggs with whole grain toast, milk and oatmeal, and whole grain pasta and tuna.
Remember how crucial it is to consume enough calories. To gain strength and build muscle, you need calories. So be sure to include enough calories in your meals and snacks if you’re on intermittent fasting.
You don’t have to eat exclusively “clean,” but you shouldn’t overeat processed junk food.
Eat a well-balanced diet with enough vitamins and minerals.
- The Timing Of Meals Is Important.
The frequency of your meals depends on the type of intermittent fasting you practice.
Eating just before a moderate to intense workout is crucial, so your body has some glycogen (stored energy) to use.
Slower, steady-state cardio can be performed whether you are fasting or not. But it would help if you did this while paying close attention to how you feel. Eat a meal soon after your workout if you experience weariness, weakness, or dizziness.
Before beginning a new fitness or nutrition regimen, always check with your doctor, especially if you have a condition like diabetes.
- One Size Schedule Does Not Apply To All
When it comes to nutrition, fasting, and exercise, there is no one-size-fits-all approach. Take your time adjusting to the new way of eating, and think about introducing workouts gradually if you’re new to exercise or intermittent fasting.
If you follow the 16:8 fasting schedule and can only work out in the mornings, you can change the eating window so that you can eat immediately after your workout. Strength training might be a terrific addition if you can lift weights around midday because you’ll be well-fueled before and after the activity. You might be more flexible if you concentrate on low-intensity exercises like gentle yoga or walking.
When Should You Exercise While On Intermittent Fasting?
You can exercise any time throughout or just before your eating window.
This is because protein is essential for muscle gain. Your muscle protein balance—the ratio of your muscle protein production to your muscle protein breakdown—determines everything.
Your muscles have access to plenty of energy and all the nutrients required to thrive when you’re fed. You continuously lose a little muscle mass while fasting.
Then there’s strength and resistance training.
Your muscle protein breakdown, which is responsible for muscle remodeling, adaptation to training, and increasing muscle mass, increases when you lift weights. This is why you should not avoid lifting weights20,21.22,23.
In other words, you lose less muscle after a fasted workout than you do after fasting and resting. However, you don’t begin putting on muscle until you eat24.
Train when your muscles have access to protein after a workout for maximum benefits. They won’t develop without it.
Do your workouts either at some point throughout your feeding window or just as your fasting period is about to end. Training while fasting is acceptable as long as you eat afterward and more importantly, as long as you feel okay and can do well.
While practicing intermittent fasting, you are not required to train in a specific manner.
The most crucial thing you can do is pay attention to how your body feels with your diet and exercise habits.
For instance, shifting your meal window and consuming a small amount of food prior to working out may be helpful if you discover that you feel exhausted after fasted exercises.
Light lifting before a meal can be an option for you if you’re the type of person who dislikes having food in their stomach while exercising.
Fasted weight training may be your answer if you want to burn fat and develop muscle. Though the finest benefits will come from lifting weights (especially heavier ones) during your eating window.
However, do thorough research before jumping into fasted training. Keep in mind that although it offers potential benefits, there are still possible side effects if you lift weights while on intermittent fasting.
Always talk to your doctor or medical professional if you feel something unusual. Ultimately, it truly comes down to what motivates you to work hard while also making you feel your best.
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