a glass of water, hydrated in hot weather, water-only fasting

Public health officials concerned about the epidemic of diabetes and pre-diabetes have focused on weight loss through exercise and healthy eating. A new study suggests that routine water-only fasting one day a week can pull cholesterol out of the fat cells.

How Could Intermittent Fasting Help?

There have been several studies of alternate-day fasting as a way of achieving weight loss or blood sugar control (Metabolism, Jan., 2013; Nutrition Journal, Nov. 12, 2013; American Journal of Clinical Nutrition, Nov., 2009). In most of these studies, people eat dramatically less (but still something) on the fast day. The body’s adaptation to fasting seems to be beneficial in many respects.

Water-Only Fasting:

Researchers at the Intermountain Heart Institute had observed that people who regularly fasted had a lower risk of diabetes and heart disease. As a result, they enrolled healthy subjects and people with prediabetes and metabolic syndrome in this clinical trial.

During the 24 hours of the zero-calorie fast, blood cholesterol levels rise. But with periodic water-only fasting once weekly over six weeks, cholesterol levels actually fell slightly. The individuals with pre-diabetes also lowered their insulin resistance. The study volunteers included both obese and normal-weight people. They lost an average of three pounds during the study.


The scientists presented their findings at the American Diabetes Association Scientific Sessions, in San Francisco on June 14, 2014. They don’t appear to have published them in the intervening two years.

Instead, they published a comprehensive review trying to determine whether therapeutic fasting regimens have clinical benefits for patients (American Journal of Clinical Nutrition, Aug., 2015). They concluded that more high-quality research is needed before fasting (intermittent or otherwise) can be recommended as a health intervention.

The People’s Pharmacy Perspective:

Water-only fasting once a week sounds like an interesting tactic to lower cholesterol and reduce the risk of progressing from pre-diabetes to diabetes. Other scientists have shown that intermittent energy restriction changes insulin responses and the way the body handles lipids following a meal (British Journal of Nutrition, March 28, 2016). This might explain the results that the Utah researchers found.

If you think about human evolution, it makes sense that periodic fasting would be tolerable if not actually beneficial. Over the course of millennia, our forebears often encountered periods when they would have little or nothing to eat for a day or two.

Learn More:

In pre-diabetes, blood sugar is elevated, but still falls below the cut-off for a diagnosis of diabetes. We discuss other ways to ward off diabetes or reduce the likelihood of complications in our Guide to Managing Diabetes. You will also find a number of methods to reduce blood fats in our Guide to Cholesterol Control and Heart Health.

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  1. James V
    Southern Oregon

    What is the source of the statement that adding cinnamon to coffee will lower blood sugars?

    I’ve read such statements on the internet but, all without citations.

    I have not PubMed yet.

  2. Kassandra

    It says “water only” and also says “no calories” for 24-hours. Does this mean that tea or coffee would be allowed as long as nothing is added to them?

  3. Mary Jane

    Anything that gets Americans to eat less is beneficial. Fasting has a long history in all cultures, and we shouldn’t ignore it.

  4. Daisy Mae

    This sounds like a good idea for a new year’s resolution (if one is into that). Commit to one or two months, then revisit your resolution. You should see some results by then and not feel guilty about giving it up if you don’t see the results you were hoping for.

  5. Steve
    raleigh, nc

    The headlines caught my attention, but upon reading the text, this sounds like dubious advice for the general public. The text suggests doing this on a weekly basis, which seems too often to be healthy or wise, and the supposed benefit, according to the text was a slight reduction in cholesterol levels… I used to do something like this when I needed to lose weight, and it helped me gain control over my stomach, but now that I’ve got the control, I see no advantage in fasting, as I need to keep food in the “pipeline” to avoid constipation and related problems from not eating enough. FYI, when I did practice something like this, I would make it a two day process, with the first day being only liquids, to soften the body shock, and the second day, only water, and very meager meals the day after the fast, as my whole purpose was to shrink my stomach and help me adjust portion sizes.

  6. Ernest
    Albuquerque, NM

    Suggest reading “The Complete Guide to Fasting” by Jason Fung, MD. This book was just published this year and contains a wealth of research references.

  7. Ben
    Blacksburg VA

    I regularly fast from 8pm to noon (16 hrs). Just liquids. Makes me feel better most days. Not sure if there is any link but I just had my blood work done and all indices were very good. Some had been borderline before.

    • The People's Pharmacy

      Dr. Ronat, the report was presented at a scientific meeting and hasn’t yet been published. That is why there was no link; it should also serve as a bit of a red flag. Peer review of research sometimes catches flaws that are not apparent in meeting abstracts.

  8. pp

    I would like more information about this.

  9. PattiC

    Very Interesting news! I found articles on google news and they said it lowered the cholesterol about 12%. I used to fast to lose weight, can’t say as it helped that much but one day is all I’d be able to handle now. :-) Thanks for the heads up!

  10. paul43

    I would appreciate more info on this subject. Thank You

  11. cara

    I knew it would come to this some day. People telling us not to eat. The body was made for food. We need nutrients. It’s true if a person doesn’t eat they won’t get fat nor have diabetes. I realize not eating one day a week isn’t going to harm a healthy person, but some people should never fast. When is common sense going to prevail?

  12. anvelaga

    We, Indians, have religious belief of water only fasting every 15 days – the trend which is declining because of ‘modern’ life style and following blindly the ‘fast food’ culture (no offense but it is the truth). Since there is no ‘scientific evidence’ like above it was never considered a beneficial habit just like the new found “Squatty Potty” (which is the old fashioned way of going to potty in India), benefits of Yoga/meditation as well as using herbs/kitchen ingredients for home remedy. I do appreciate people’s pharmacy for providing the beneficial articles/information. – Thank you

  13. Cathie

    Does this mean no food for the 24-hours or does it mean tat the only liquid we should’ve is water during that time? I am concerned about having no food in a 24-hour period because that makes me feel a bit sick.

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