To Fast or Not to Fast before your workout
With fasting being a big hot topic lately, I thought I would address a common question I get regarding fasting and exercise. Should I eat before my workout or exercise fasted?
Let's start with addressing the why. Why would one consider exercising while fasted? There are several opinions on fasted workouts. First, when you have food in your stomach, your insulin levels are increased. This means that your body is in storage mode rather than fat burning mode. Second, some studies suggest that fasted workouts help to burn more fat due to the decreased amount of glycogen stores for fuel. The theory is, that if there isn't enough glycogen to burn, the body will have to burn fat for fuel. Unfortunately, the jury is still out on whether or not this is 100% true but even if you want to give it a try, there are a few things to consider.
1. What will your workout consist of? If you're workout is strength based (resistance training, weight lifting), you might want to think about ensuring your body has enough fuel in order to actually benefit from the workout. If you're lifting weights and your body doesn't have enough stored fuel, there's a chance that your body will start to breakdown muscle. Which might be contradicting the main reason you're actually in the gym! If you're workout is mostly cardio based (running, sprinting, cycling etc.) fasted might actually help you. For one because you won't feel weighted down by food in your stomach. Two, fasted cardio can help increase endurance and burn more fat. So before jumping into your workout fasted, you should determine what your workout will be then decide to fast or not.
2. Timing is important! If you're working out first thing in the morning, you'll have more glycogen stores in your body to help fuel your workout regardless of what it is. If you're working out later in the day and haven't eaten yet, your glycogen stores are pretty depleted and you might do better eating before you exercise. You're also more likely to feel faint, dizzy, or light headed towards the end of a fast so make sure you think about timing when considering a fasted workout.
3. How well do you know your body? Are you the type of person who can skip meals and not skip a beat? Or are you the type that feels shaky, famished, headache, etc. if you miss a meal? If you're the second, you should probably second think fasted workouts.
4. What's your stress like? If you're working a high stress job or live a high stress life, adding in fasted workouts could add even more stress which could be harmful to your health. Stress puts your body in fight or flight mode. You're body doesn't know the difference between being stressed from work, or being stressed from no food. All it knows is it needs to find a way to survive. This means that it will increase the stress hormone cortisol. Prolonged elevations of cortisol in the body can actually stunt fat burning and increase fat storage. It could also be harmful to your hormone health to be in such a state of stress. Make sure you consider your stress levels when considering fasted workouts.
5. What's your main goal? If your main goal is to build muscle, increase strength, gain mass or weight, then you most likely need the fuel before you workout. If you're main goal is to burn fat or lose weight, fasted cardio could benefit you as mentioned above with an increase in fat oxidation. You need to consider your goals, why you want to train fasted and if it's right for you before jumping in.
Most important thing about fasted workouts and fasting in general is to listen to your body! Make sure you are hydrated, make sure you have had enough sleep, aren't stressed, and don't have any health issues. Then be sure to pay attention to your body before, during and after your workout. If you feel dizzy, light headed, faint, moody, get a headache, feel brain fog, fatigue, or notice any other changes, stop and forget about fasting! It can be very dangerous to your health and body so be sure to know what you are doing!