Quick Tip - Fast for 24 Hours to Understand the Difference between Hunger and Cravings

Girl Drinking Water

Fasting, that is, not consuming calories, is about to become all the rage within the health and wellness sphere (more on that soon). The incredible benefits of fasting are numerous, from extending lifespan (1) to curing diseases (2), and fasting is certainly a wellness tool everyone should learn to use properly in their quest for optimal health. Fasting has such powerful effects upon the body because it removes a key component to life, food. Basically the larger the lever you pull (water, sleep, food, sunlight, air quality, etc), the larger the potential effect, positive or negative.

When an organism starts to fast, cellular autophagy ramps up (3) and fat metabolism increases (4), and a whole host of other important bodily systems are tweaked, many of which we have yet to understand scientifically. I want to be clear, fasting is a powerful tool, and not a tool to be used irresponsibly.

The increasingly worrying trend within the wellness field is the use of fasting for the sole purpose of losing weight. Because fasting is free and requires little more than perseverance, water, and electrolytes (for extended multi-day fasts), it has a low barrier of entry for anyone to try, no matter how inexperienced. While extended multi-day fasting can be a powerful weight loss tool, a better approach for those new to fasting is to start small with a 24 hour fast first, and potentially experiment with longer fasts from their after consulting with their doctor.

Hunger vs Cravings

With a 24 hour fast, you will not lose drastic amounts of body fat, but what you learn is even more valuable. Fasting is a fantastic way to learn how to differentiate between two types of hunger everyone has experienced: Physiological hunger and psychological hunger (also known as cravings). A good example demonstrating the difference can be summarized with the following hypothetical conversation:

Rebecca - “Oh my god I’m so hungry! Hey Dave what should we have for dinner?”

Dave - “I’m ravenous too! How about we grab some burgers?”

Rebecca - “I’m not feeling burgers, does Mexican food work (cravings)?”

Dave - “Yeah sure I’ll eat anything (hunger)!”

Dave was experiencing physiological hunger. His body required calories, and anything would do. Rebecca on the other hand wasn’t actually hungry. She wasn’t hungry for a burger, but she was craving Mexican food. If Rebecca was more aware of the difference between hunger and cravings in this instance, she might have decided to not eat again until she was actually hungry, therefore consuming less calories and likely maintaining a healthier body weight.

Man Clutching his Growling Stomach

The first time you fast for 24 hours, and it was a conscious decision, you start to learn the difference between cravings and hunger. You might experience cravings a few times, with instances like your coworker bringing in donuts or grocery shopping triggering those psychological urges. By remaining strict and continuing your fast, you’ll find that after 10-30 minutes the craving has passed and you are no longer “hungry”.

A 24 hour fast will also teach you how your body becomes adapted to receiving food at regular intervals. Eat breakfast everyday at 7 am? Guaranteed your stomach will start growling at 7 am or shortly afterwards. That signal isn’t necessarily a sign that you’re hungry, it’s just your stomach contracting via muscle memory as it’s used to processing food around that time. Once again, 10-30 minutes later, the stomach growling will have passed, and the perceived sensation of hunger will be gone.

It’s Only 24 Hours

Try it out! First schedule a 24 hour fast on a day where there will be little if any food temptations, and once you successfully complete that, do a 24 hour fast on a day filled with temptations. Armed with the knowledge that you’ve already successfully completed a 24 hour fast, when you encounter cravings, pressure from others to eat, and hunger pangs, you’ll be well equipped to handle the situation in order to successfully complete the 24 hour fast. If you slip up, just try again!

We’re all given the same 24 hours everyday, how will you use them?


  1. De cabo R, Carmona-gutierrez D, Bernier M, Hall MN, Madeo F. The search for antiaging interventions: from elixirs to fasting regimens. Cell. 2014;157(7):1515-26.

  2. Documentary. The Science of Fasting. Directed by Sylvie Gilman and Thierry de Lestrade.

  3. Jung CH, Ro SH, Cao J, Otto NM, Kim DH. mTOR regulation of autophagy. FEBS Lett. 2010;584(7):1287-95.

  4. Knapik JJ, Meredith CN, Jones BH, Suek L, Young VR, Evans WJ. Influence of fasting on carbohydrate and fat metabolism during rest and exercise in men. J Appl Physiol. 1988;64(5):1923-9.