Have you ever woken up late for work and accidentally skipped breakfast?

Turns out you’ve also practised intermittent fasting (IF).

In fact, you are intermittently fast every day whether you realise it or not.

Let’s say you finish eating your dinner at 8 pm and aren’t eating breakfast until 8 am, guess what, you’ve just fasted for 12 hours.

While calories, macros and meal plans focus on WHAT you should eat, intermittent fasting is the practice of WHEN you should eat.

The most popular methods are:

The 16/8 method, also known as The Leangains Protocol (popularised by Martin Berkhan). This involves a 16-hour fasting period followed by an 8-hour eating window, for example eating between 9 am-5 pm or 1 pm-9 pm. Most advocates skip breakfast as they find it works better from a social perspective.

The 5:2 diet involves eating normally 5 days a week and only 500-600 calories on the other 2 days.

Eat-Stop-Eat, popularised by Brad Pilon. This method involves a 24 hour fasting period 1-2 times per week. For example, you eat dinner at 8 pm on Monday and wouldn’t eat again until 8 pm on Tuesday.

So what do all these have in common? Perhaps you guessed it - they can help limit caloric intake!

Restricting the windows in which you eat, or the amount you eat creates a more favourable situation for a caloric deficit to occur. That’s not to say it’s always the case however, this stuff isn’t magic. You can still overeat significantly in an 8-hour eating window.

What else? Here are a few other benefits you might experience from short term fasting:

• Improved insulin sensitivity, helping you access stored body fat and reduce the amount stored(1).
• Short term fasting increases metabolic rate slightly via increasing growth hormone and norepinephrine release(2).
• Reducing inflammation in the body: a known to be a driver behind many diseases(3).
• Preserving muscle mass: one study found that intermittent fasting prevented muscle loss better than other calorie restriction methods(4).

Now to the question, is fasting worth it? Maybe. It’s highly individual.

Many people find skipping a meal to be a convenient way hit their calorie goals when working in a deficit, while others find the meals during the day to be too much food to consume in the smaller eating window.

Some people perform just fine in the gym while fasted, while others see a significant performance impact. This will also vary depending on the type of activity you’re doing.

No matter what style of fasting you experiment with, there is a phase of adaptation that should be considered. The first time you skip breakfast, you’re going to be starving. Over time, however, your hunger hormones adjust and you won’t notice it as much.

So there you have it, decide for yourself if intermittent fasting is worth trying for you personally.

References

Barnosky, A., Hoddy, K., Unterman, T. and Varady, K., 2014. Intermittent fasting vs daily calorie restriction for type 2 diabetes prevention: a review of human findings. Translational Research, 164(4), pp.302-311.

Johnson, J., Summer, W., Cutler, R., Martin, B., Hyun, D., Dixit, V., Pearson, M., Nassar, M., Tellejohan, R., Maudsley, S., Carlson, O., John, S., Laub, D. and Mattson, M., 2007. Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma. Free Radical Biology and Medicine, 42(5), pp.665-674.

Mansell, P., Fellows, I. and Macdonald, I., 1990. Enhanced thermogenic response to epinephrine after 48-h starvation in humans. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 258(1), pp.R87-R93.

Varady, K., 2011. Intermittent versus daily calorie restriction: which diet regimen is more effective for weight loss?. Obesity Reviews, 12(7), pp.e593-e601.