Health and Fitness,  Lifestyle

FAQ: This is What Happens When You Fast for 24 Hours (in a Nutshell)


So what really  happens to your body during a 24 hour fast?

  1. Believe it or not, you will not shrivel up and wither away! Our bodies are  smarter than they (sometimes) appear and have biochemical mechanisms in place to adapt.
  2. Eight hours after your last meal, your body enters the “fasting” state because it takes about that long for your body to FULLY digest and absorb all nutrients (depending on the content of your pre-fast meal).
  3. At this time, your body uses its carbohydrate [glucose] stores (AKA glycogen) to provide energy.
    After an overnight fast, you will mostly deplete your liver glycogen stores. Research shows that after a 24-hour fast, without exercise, muscle glycogen stores were reduced by about 50%.
  4. Once you use up your glucose stores, your body breaks down your fat stores for energy, but of note, your body does start to utilize fat before your glucose stores are fully depleted. This is why researchers suggest that “intermittent fasting” can rev up your fat-burning mechanisms (it’s physiology!).



In a prolonged fast, your body will also start breaking down your muscles to utilize protein for energy.

How does our body know to which source of energy to use? I’m going to skip the details (for now) to avoid getting too scientific for you, but it’s hormonal changes that occur during fasting, which mediate these biochemical processes outlined above.

How Should We Break Our Fast?

Here are my tips for the best way to break a fast:

  • Drink water (especially if you haven’t for 24 hours, which is common for religious fasts).
  • Have a small meal full of nutrient-dense foods like fruits and vegetables.
  • Chew your food well. A minimum of 30 chews is suggested for each bite! (okay mejo OA to / okay this is exaggerating!)
  • Focus on foods that are easy to digest — try cooked vegetables over raw.
  • Eat foods you know your body previously tolerated well.
  • Don’t think about your break-fast meal as “making up” lost calories. You don’t want to get sick from overeating!

Original source: https://www.precisionnutrition.com (added slight edits)



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