What are the Health Benefits of Fasting?

Will fasting make you healthier or help you lose weight?

Monica Reinagel, M.S.,L.D./N
4-minute read
Episode #60

How to Fast Safely

Fasting is not for everyone. Though some people describe feeling euphoric and energized, others feel cranky and sick. And if you’re pregnant, diabetic, severely underweight, recuperating from surgery, or have a serious medical condition, you really shouldn’t fast without close medical supervision. In fact, those with medical conditions are often exempted from religious fasting obligations.

If none of that applies to you and you think you’d like to try an occasional fast, here are some guidelines on how to do it safely.

  1. Keep it short. You don’t have to fast for days at a time to get the metabolic or weight loss benefits. As some of the studies I’ve posted demonstrate, skipping a meal every other day is enough to produce modest weight loss. Fasting for as little as 20 hours at a time is enough to improve insulin sensitivity and other metabolic functions. I don’t recommend going for longer than 36 hours.

  2. Stay hydrated. Those fasting for Ramadan and Yom Kippur usually go without water throughout their fasts. Although no lasting harm appears to come from it, they do often end up somewhat dehydrated. That’s why Ramadan feasts traditionally begin with fruit, soups, and other hydrating foods. If you are not fasting for religious reasons, by all means drink plenty of water during your fast.

  3. Forego vigorous exercise while fasting. A brisk walk is fine but it’s not a good idea to run a marathon or swim the English Channel on a day when you’re not eating as much as usual.

  4. Avoid operating heavy machinery. Don’t operate any heavy machinery--such as automobiles-- until you know how feel while fasting. In Muslim countries, car accidents tend to go up during Ramadan. Then again, that may not be all due to the fasting. A good bit of it may be due to sleep deprivation. Families and friends often gather to break the fast and visit until the wee hours—then get up early for another meal before the fast begins again.

  5. Optimize your nutrition. When you’re not fasting be sure to eat wholesome, nutritious foods. If you’re going to eat less, the nutritional quality of what you do eat becomes that much more important. Fasting for a day and then pigging out on junk food the next day is not a way to move your health agenda forward.

  6. Don’t go too low. If your weight starts to dip below your healthy weight range, you’re fasting too often and may be at risk of nutritional deficiencies. Not sure what your healthy weight range is? I’ll put a link in the show notes to a calculator.



These tips are provided for your information and entertainment and are not intended as medical advice. Because everyone is different, please work with your health professional to determine what’s right for you.

Got a question or a comment for me?  Find me on Facebook and Twitter.

Have a great day and eat something good for me!


Benefits of fasting for weight control and disease prevention (U.S. News and World Report)

Effect of intermittent fasting on insulin action (Journal of Physiology)

Effects of intermittent fasting on cardiovascular health (Annals of Nutrition and Metabolism)

A Year of Intermittent Fasting (Blog of one man’s experience)

Pros and Cons of Modified Fasting for Weight loss (Monica’s Nutrition Over Easy Blog)

What’s a healthy weight? (BMI Calculator)

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