Intermittent Fasting with Long Fasts : Dangerous or Beneficial ?

Building up to a long fast

If you’re new to intermittent fasting, first sit back and get comfortable with the daily 16-ish hour fasts for at least a month. Let your body and mind adjust.

If you’re a more seasoned faster who has hit a weight plateau, wants to boost results, or gain the additional health benefits, a periodic long fast of up to 48 hours might be a great fit. Start with a goal of 24-36 hours the first time and build to a 36-48 hour fast.

The most important thing is to honor your body. There’s a difference between low energy because you haven’t eaten in a day and a half and actually feeling ill. Pay attention to what your body is experiencing and adjust as needed. Don’t push yourself to a dangerous place for the sake of a few additional hours of fat burning.

Long fast tips

A woman explaining something to another woman.
  • Stay hydrated! Twenty percent of our water intake usually comes from our food, and since you won’t be eating, it is essential to make sure you are drinking plenty of allowed liquids. During the long fast, you can have water, black coffee, and unsweetened tea.
  • Be careful of low electrolyte levels if fasting over 36 hours. Electrolytes keep you hydrated (4). Ingest a pinch of salt, take electrolyte supplements, or drink bone broth.
  • Ease back into eating with a small snack, like a handful of nuts or a protein shake.
  • An hour or two after your snack, have your first meal, focusing on healthy fats like avocado and coconut oil.
  • Eat iodine-rich foods (like seaweed, shrimp, tuna, or eggs) following a fast to support the production of your thyroid hormones. This is especially important for women (5).

Downsides of long fasts

While the benefits of periodic long fasting are many, there are some drawbacks to fasting for more than a day, including hunger, dizziness, sluggishness, and exhaustion. Long fasts can also make social situations uncomfortable.

Who should avoid long fasts 

The following people should either avoid or be extra cautious if fasting over 24 hours:

  • those with type 1 diabetes
  • those with low blood pressure
  • those who are underweight or have a history of eating disorders
  • women who are pregnant, breastfeeding or trying to conceive

Mix up your intermittent fasting routine with a 24-48 hour fast periodically to boost your long-term results.

If you need help with intermittent fasting, join our intermittent fasting community for women only. There you get all the support you need!

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