Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

A century ago, fasting—starvation as a therapeutic measure—was described as the ideal measure for obesity (as you can see, fat shaming is not a new invention in the medical literature). I’ve extensively covered fasting for weight loss in a nine-video series starting with this one, but what about all the other purported benefits? I do have a video series on fasting for hypertension, but what about psoriasis, eczema, type 2 diabetes, lupus, metabolic disorder, rheumatoid arthritis and other autoimmune disorders, depression, anxiety—why hasn’t it been tested more?

One difficulty with fasting research is: what do you mean by fasting? When I think fasting, I think of water-only fasting, but in Europe they tend to practice so-called modified fasting, or Buchinger fasting, which is more like a very low-calorie juice fasting with some vegetable broth. Some forms of fasting may not even cut calories at all. Ramadan fasting is when devout Muslims abstain from food and drink from sunrise to sunset, yet interestingly, they end up eating the same amount, or even more food, overall.

The largest study on fasting to date was published in 2019. More than a thousand individuals were put through a modified fast, cutting intake down to about 10 cups of water, a cup of fruit juice, and a cup of vegetable soup a day. They reported very few side effects, which is in contrast to the latest water-only fasting data, which only involved half as many people, but reported nearly 6,000 adverse effects. Now, the modified fasting study did seem to try to undercount adverse effects, only counting reported symptoms if they were repeated three times, but still only reporting single cases of things like nausea, feeling faint, upset stomach, vomiting, or palpitations, whereas the water-only fasting study reported about one to two hundred of each. What about the benefits, though?

In the modified fasting study, participants self-reported improvements in physical and emotional well-being, along with a surprising lack of hunger. And the vast majority of those who came in with a pre-existing health complaint reported feeling better, with less than 10 percent reporting their condition worsening or remaining unchanged. They weren’t just fasted though, but engaged in a lifestyle program, which included being placed before and after on a plant-based diet. Too bad they didn’t have some people just do the healthier diet without the fast to tease out the fasting effects.  Oh, but they did! About a thousand folks fasted for a week on the same juice and vegetable soup regimen versus those put on a normocaloric (meaning normal calorie) vegetarian diet the whole time.

Both experienced significant increases in both physical and mental quality of life, and interestingly ,there was no significant difference between the groups. In terms of their major health complaints—rheumatoid arthritis, chronic pain syndromes like osteoarthritis, fibromyalgia, and back pain, inflammatory and irritable bowel disease, chronic pulmonary diseases, and migraine and chronic tension-type headaches, the fasting group appeared to have an edge, but both groups did good, with about 80 percent reporting improvements in their condition, with only about 4 percent reporting feeling worse.

Now, this was not a randomized study; people chose which treatment they wanted; so maybe, for example, those choosing fasting were sicker or something. The improvements in quality of life and disease status were also all subjective self-report, which is ripe for placebo effects, no do-nothing control group, and the response rates to the follow-up quality of life surveys were only about 60-70 percent, which also could have biased the results. But extended benefits are certainly possible, given they all tended to improve their diets. More fruits and vegetables, less meats and sweets, and therein may lie the secret. Principally, the experience of fasting may support motivation for lifestyle change. “Most fasters experience clarity of mind and feel a ‘letting go’ of past actions and experiences, and thus may develop a more positive attitude toward the future.”

As a consensus panel of fasting experts concluded, “Nutritional therapy is a vital and integral component of fasting. After the fasting therapy and refeeding period, nutrition should follow the recommendations… of a plant-based whole-food diet….”

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