Intermittent Fasting and Exercise

Intermittent Fasting (IF) is an increasingly common way of eating that has become popular over the last few years. IF is also known as time-restricted eating, where the aim is to restrict when you eat, rather than necessarily what you eat.  A recent review of the science of fasting shows that it can improve metabolism, lower blood sugar and lessen inflammation.  It can also help clear out toxins and damaged cells, which lowers risk for cancer and enhances brain function.

How Does Fasting Work?

Put simply, our insulin levels will drop between meals, and as readily available glucose is used up, our fat cells release their stored sugar to be used as energy.  This process can facilitate weight loss and cellular repair in the body. Studies have also showed that intermittent fasting causes less muscle loss than the more standard method of continuous calorie restriction.

If you think IF is something you want to incorporate into your lifestyle, the question is then, how do you exercise safely when it comes to this type of eating?  After all, food is our body’s fuel whenever we are exercising, and with intermittent fasting, you are going through long periods of time without ingesting any type of food and drink, let alone the protein or carbohydrates we normally associate with performance nutrition.

How to Exercise with Intermittent Fasting: 

Listen to your body

Start out by keeping cardio workouts at an aerobic level whenever you are fasting by making sure you are still able to hold a conversation. While it is possible that initially your performance may decline, recent studies have shown that as long as athletes maintain their total intake of calories and micronutrients and their typical sleep quality, they likely would not see any negative effects on performance.

So, if you feel like you are pushing the boundaries of your body, don’t be afraid to stop.

That doesn’t mean that there’s something wrong, it may simply mean that you have to keep practicing and finding the intensity that you are able to handle during the upcoming weeks.

Practice high-intensity workouts after you eat.

If you have a hard or intense training block coming up, it may not be the right time to start fasting.  Some sessions can be done fasted, however keep in mind they may ‘feel’ harder than usual.  Try scheduling your hard workouts after eating to give you enough energy to fuel your body.

Of course, recovery is vital, so if you are doing a hard session in a fasted state and continue the fast, you will miss the vital nutrients you need in recovery such as protein and carbohydrates. This means you will not maximise the benefit from your workout, and can leave you more prone to illness and injury.  Again, time your harder or more intense workouts carefully so that you can eat afterwards to maximise your recovery and workout gains.

Keep your body hydrated

Hydration is always important, but never more so than when you exercise and fast.  We know that electrolytes are lost in sweat, and it is vital they are replaced.  Any fast over 12 hours also increases the likelihood of electrolyte deficiency. This is due to a reduced intake of electrolytes from food, and also because lower insulin levels results in the kidney expelling more electrolytes than usual.

Simply hydrating with water is not enough; it is essential to replace electrolytes using a sugar-free solution such as Bindilyte for all the sodium, potassium, magnesium and calcium your body requires on a regular basis.

Thinking of starting a fast?

If you have particular body goals such as weight reduction or reduced inflammation, then fasting could be a lifestyle worth exploring.

As with any nutrition changes, be sure to take it slowly, and do not expect your body to perform at its best right away.

Finally, be careful to maintain your electrolytes and hydration at all times during fasting to make sure you stay in the best shape possible to hit your workout targets.

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