Fasted Running: The Pros and Cons
Intermittent fasting has taken the fitness world by storm, with proponents of this calorie control method swearing by it for achieving a better state of being. Athletes, in particular, are gung-ho about intermittent fasting, claiming that it helps them maximize their muscle gain while boosting metabolism. One of the most popular fitness trends out there nowadays is fasted running. Those who practice it say that it has made a world of difference to their fitness levels while helping them shed fat. This article delves into the world of fasted running, looking into its pros and cons, and tries to give you a ringside view into what is now undoubtedly a major health trend.
Fasted running is popular for two main reasons. Firstly, there is a camp of followers who feel they do not have sufficient time in the morning to eat before going on a run. They also find that running on a full stomach causes cramps. The other camp of followers goes for fasted runs because they want the added benefits of running on an empty stomach, like fat loss.
A Quick Look at Intermittent Fasting
Intermittent fasting involves going without food for a certain number of hours a day and consuming all your calories in the remaining hours. These periods are known as the fasting window and feeding window, respectively. It has been claimed that intermittent fasting helps to lose weight, improve insulin levels, improve cardiovascular health, improve brain health, and potentially prevent cancer. During fasting, the body uses up all its glycogen stores for energy and undergoes a metabolic switch wherein it enters a state known as ketosis. In ketosis, the body breaks down its fat stores to make ketone bodies that fuel the body in the absence of glycogen.
Intermittent fasting is a favorite with athletes as it helps them build more muscle while boosting their metabolic rates. Anabolic fasting, in particular, helps with this. From rank beginners to hardcore fasters, intermittent fasting has something for everyone. It has various routines and schedules that can be customized according to your needs. During fasting, it is important to drink enough water to stay hydrated. If you feel hungry, go for a shot of lemon water to keep yourself satiated. If you are starving, sip a cup of bone broth during your fasting window. Remember, you must avoid consuming any calories during the fast to reap the maximum benefits of intermittent fasting.
What is Fasted Running?
Simply put, fasted running means that you run on an empty stomach. Another way of defining it is that you run after going through a long period without food. The majority of people practice fasted running as the very first activity in the morning before they have breakfast or consume any kind of pre-run snacks. Running is an intense activity that requires lots of energy. This is why eating normally in the non-fasting hours leading up to the running time is crucial. This means you must consume enough nutrients to get sufficient energy to take care of running demands and other activities in your daily routine.
Based on the caloric intake and volume of the last meal you had, if four hours have passed after your last snack or six hours have passed after your last meal, you are doing fasted running. Besides getting sufficient energy for your running sessions, looking after hydration and recovery is also important. Depending on the kind of intermittent fasting you are doing, fluids may or may not be a part of your schedule. It is very important to be hydrated adequately to compensate for the fluid and salt loss during running. You must also consider recovery after the running session. You need to pay attention to your running schedule so that you can plan your fasting periods to accommodate recovery times. During recovery, your body will have to replenish the energy it burnt during your exercise session. To do this, it has to have a ready supply of sugars, nutrients, and amino acids.
Benefits of Fasted Running
There are quite a few benefits attached to fasted running. Check them out here:
Fasted Running Could Increase Fat Oxidation
Fasted running increases fat oxidation, meaning that a larger percentage of calories you burn as you run comes from stored body fat instead of stored glycogen in the muscles. Your body has limited glycogen stores in the skeletal muscles and the liver; these levels will go down overnight during fasting. An athlete who is endurance trained can store up to 2,000 calories in the form of glycogen in the muscles and the liver, while other runners can store about 1,500 calories. This is why, when doing fasted running, your body will try to conserve these limited glycogen levels and instead burn fat for energy.
A study has shown that you can burn 20% more fat during endurance training, like running on an empty stomach. 
Fasted Running Could Improve Digestive Problems
If you have a sensitive stomach, you might find that fasted running reduces gas, side stitches, cramping, bloating, and runner’s trots. Studies have discovered that you are more likely to have nausea while running if you are running on a full stomach.  During exercise, blood gets diverted from the digestive tract to meet the enhanced oxygen demands of muscles. Your digestion will cease, and anything sitting around your stomach will stay there without getting digested. This irritates the gut, causing nausea, gas, and bloating.
If you have a sensitive stomach, even snacks can cause nausea. Hence, fasted running will be a good option for you.
Fasted Running Brings Greater Loss of Weight
Studies have shown that exercising on an empty stomach will cause you to consume fewer calories during the day.  Possibly, fasted running decreases appetite by suppressing the hunger hormone ghrelin. Hence, while fasted running does not directly cause weight loss because it will not consume more calories compared to running on a fed stomach, it is likely that it will lead to a greater loss of weight due to the decreased appetite.
Cons of Fasted Running
Despite the benefits, fasted running has some downsides that you should be aware of:
Fasted Running Can Lead to Muscle Loss
When you run on an empty stomach, your body will use up its glycogen stores, and then it will turn to breaking down muscle protein to create glucose. This means that if you run for too long on an empty stomach, your body will start to break down muscle mass to fuel your run. This is especially true if you are not consuming enough protein in your diet.
Fasted Running Can Lead to Poor Performance
Your body needs fuel to perform at its best. When you run on an empty stomach, you are depriving your body of the fuel it needs to perform at its peak. This means that you may not be able to run as fast or as far as you would if you had eaten before your run.
Fasted Running Can Lead to Low Blood Sugar
When you run on an empty stomach, your blood sugar levels can drop quickly. This can lead to symptoms like dizziness, lightheadedness, and even fainting. If you have diabetes or any other medical condition that affects your blood sugar levels, you should talk to your doctor before trying fasted running.
Fasted running can be a great way to boost fat loss and improve digestive problems. However, it is not for everyone. If you are new to running or have any medical conditions that affect your blood sugar levels, you should talk to your doctor before trying fasted running. If you decide to give it a try, be sure to pay attention to your body and stop if you experience any negative symptoms.