What You Need to Know About Fasted Exercise

What You Need to Know About Fasted Exercise

Exercising while fasted is a common practice for many people who get up too late to have breakfast before their spin class starts or who simply can’t stomach food early in the morning. 

But did you know that there are benefits to exercising fasted?

More than that, if it is something you haven’t tested out and having to eat before working out makes you less inclined to hit the gym, it might be worth a try.

Here’s what you need to know:

Fasted Exercise is Best for Certain Types of Workouts

Many people are hesitant to take on fasted exercise because they have heard it is bad to exercise without eating first, or that it could be dangerous, leading to fainting, low energy, brain fog and more.  The truth is, fasted exercise is only right for certain types of workouts.  For example, if you are looking to build muscle and heading to the gym to bulk up, fasted exercise is not the answer because your body will break down muscle for energy. Likewise, if you are engaging in high intensity exercise for an extended period of time or doing exercise for a long duration – such as a marathon training run – you should fuel your body before you begin.

Fasted Exercise can Improve Insulin Sensitivity

When you start a workout fasted, your insulin levels are low because you have not had any sources of glucose in the last several hours, and your glycogen is depleted as well.  After your exercise, when you consume food again, your insulin response is hyper sensitive because it has been quite low for a period of hours.  This means you secrete less inulin and get the same results.  This is good news for people who are in the early stages of diabetes and are suffering from insulin resistance. 

Fasted Exercise can Burn Fat

The most common reason many people turn to fasted exercise is to burn fat and lose weight.  The idea is simple: because you haven’t eaten any food and do not have glucose or glycogen available – your body’s first source of energy – your body will turn to its second source, which is fat, and burn this for fuel.  The mechanics of it are more complicated than that however, and simply because you are exercising fasted does not mean your body will start burning through all its fat stores. Rather it will use what it needs to fuel you and then rely on intake of glucose afterwards.  Be aware that you aren’t over-consuming on glucose sources after your workout though, as this will negate the fat burning effects and put you into a positive calorie intake instead of a deficit.

While fasted exercise certainly has its place in a health and fitness routine, it is not for everyone.  Don’t do fasted exercise just because you think it is the ticket to weight loss, and instead, give it a try to see if it works for you and makes you feel good.

By: Laura Peill, RHN, BScH –  Viand Nutrition

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