Alternate-day modified fasting is put to the test for lifespan extension.
Does Intermittent Fasting Increase Human Life Expectancy?
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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.
Is it true that alternate-day calorie restriction prolongs life? Doctors have anecdotally attributed improvements in a variety of disease states to alternate-day fasting including asthma, seasonal allergies, autoimmune diseases like rheumatoid arthritis, osteoarthritis, infectious diseases like toenail fungus, periodontal disease, and viral upper respiratory tract infections, neurological conditions like Tourette’s syndrome and Meniere’s disease, atrial fibrillation, and menopause-related hot flashes. The actual effect on chronic disease, however, remains unclear.
Alternate-day fasting has been put to the test for asthma in overweight adults. Asthma-related symptoms and control significantly improved, as did their quality of life, including objective measurements of lung function and inflammation, significant improvements in peak airflow, significant improvements in mood and energy. But, their weight improved too—about a 19-pound drop in 8 weeks—so, it’s hard to tease out effects specific to the fasting beyond the benefits we might expect from weight loss by any means. For the most remarkable study on alternate-day fasting, you have to go back more than a half century.
The 2017 cholesterol findings were the most concerning data I could find on alternate-day fasting. The most enticing was published in Spain 61 years earlier, in 1956. The title of the study translates as “The hunger diet on alternate days in the nutrition of the aged.” Inspired by the data being published on life extension with calorie restriction on lab rats, researchers split 120 residents of an old-age home in Madrid into two groups. Sixty residents continued to eat their regular diet, and the other sixty were put on an alternate-day modified fast. On the odd days of the month, they ate a 2,300-calorie regular diet, and on the even days were given only a pound of fresh fruit and a liter of milk, estimated to add up to about 900 calories. This continued for three years. So, what happened?
Over the duration of the study, 13 died in the control group, compared to only 6 in the intermittent fasting group. But those numbers were too small to be statistically significant. What was highly significant was the number of days spent hospitalized. Residents in the control group spent a total of 219 days in the infirmary, whereas the alternate-day fasting group only chalked up 123 days. This is held up as solid evidence that alternate-day fasting may improve one’s health span and potentially even one’s lifespan, but a few caveats must be considered. It’s not clear how the residents were allocated to their respective groups. If instead of being randomized, healthier individuals were inadvertently placed in the intermittent fasting group, that could skew the results in their favor. Also, it appears the director of the study was also in charge of medical decisions at the home. In that role he could have unconsciously been biased towards hospitalizing more folks in the control group. Given the progress that has been made regulating human experimentation, it’s hard to imagine such a trial being run today; and so, we may never know if such impressive findings can be replicated.
Please consider volunteering to help out on the site.
- Johnson JB, Laub DR, John S. The effect on health of alternate day calorie restriction: eating less and more than needed on alternate days prolongs life. Med Hypotheses. 2006;67(2):209-11. https://www.ncbi.nlm.nih.gov/pubmed/16529878
- Johnstone A. Fasting for weight loss: an effective strategy or latest dieting trend?. Int J Obes (Lond). 2015;39(5):727-33.
- Johnson JB, Summer W, Cutler RG, et al. Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma. Free Radic Biol Med. 2007;42(5):665-74.
- Vallejo EA. La dieta de hambre a dias alternos en la alimentacion de los viejos. Revista Clinica Espanaola. 1956;63:25 -27.
- Trepanowski JF, Kroeger CM, Barnosky A, et al. Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial. JAMA Intern Med. 2017;177(7):930-938.
- Stunkard AJ. Nutrition, aging and obesity: a critical review of a complex relationship. Int J Obes. 1983;7(3):201-20.
Image credit: John Moeses Bauan via unsplash. Image has been modified.
Motion graphics by Avocado Video
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.
Is it true that alternate-day calorie restriction prolongs life? Doctors have anecdotally attributed improvements in a variety of disease states to alternate-day fasting including asthma, seasonal allergies, autoimmune diseases like rheumatoid arthritis, osteoarthritis, infectious diseases like toenail fungus, periodontal disease, and viral upper respiratory tract infections, neurological conditions like Tourette’s syndrome and Meniere’s disease, atrial fibrillation, and menopause-related hot flashes. The actual effect on chronic disease, however, remains unclear.
Alternate-day fasting has been put to the test for asthma in overweight adults. Asthma-related symptoms and control significantly improved, as did their quality of life, including objective measurements of lung function and inflammation, significant improvements in peak airflow, significant improvements in mood and energy. But, their weight improved too—about a 19-pound drop in 8 weeks—so, it’s hard to tease out effects specific to the fasting beyond the benefits we might expect from weight loss by any means. For the most remarkable study on alternate-day fasting, you have to go back more than a half century.
The 2017 cholesterol findings were the most concerning data I could find on alternate-day fasting. The most enticing was published in Spain 61 years earlier, in 1956. The title of the study translates as “The hunger diet on alternate days in the nutrition of the aged.” Inspired by the data being published on life extension with calorie restriction on lab rats, researchers split 120 residents of an old-age home in Madrid into two groups. Sixty residents continued to eat their regular diet, and the other sixty were put on an alternate-day modified fast. On the odd days of the month, they ate a 2,300-calorie regular diet, and on the even days were given only a pound of fresh fruit and a liter of milk, estimated to add up to about 900 calories. This continued for three years. So, what happened?
Over the duration of the study, 13 died in the control group, compared to only 6 in the intermittent fasting group. But those numbers were too small to be statistically significant. What was highly significant was the number of days spent hospitalized. Residents in the control group spent a total of 219 days in the infirmary, whereas the alternate-day fasting group only chalked up 123 days. This is held up as solid evidence that alternate-day fasting may improve one’s health span and potentially even one’s lifespan, but a few caveats must be considered. It’s not clear how the residents were allocated to their respective groups. If instead of being randomized, healthier individuals were inadvertently placed in the intermittent fasting group, that could skew the results in their favor. Also, it appears the director of the study was also in charge of medical decisions at the home. In that role he could have unconsciously been biased towards hospitalizing more folks in the control group. Given the progress that has been made regulating human experimentation, it’s hard to imagine such a trial being run today; and so, we may never know if such impressive findings can be replicated.
Please consider volunteering to help out on the site.
- Johnson JB, Laub DR, John S. The effect on health of alternate day calorie restriction: eating less and more than needed on alternate days prolongs life. Med Hypotheses. 2006;67(2):209-11. https://www.ncbi.nlm.nih.gov/pubmed/16529878
- Johnstone A. Fasting for weight loss: an effective strategy or latest dieting trend?. Int J Obes (Lond). 2015;39(5):727-33.
- Johnson JB, Summer W, Cutler RG, et al. Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma. Free Radic Biol Med. 2007;42(5):665-74.
- Vallejo EA. La dieta de hambre a dias alternos en la alimentacion de los viejos. Revista Clinica Espanaola. 1956;63:25 -27.
- Trepanowski JF, Kroeger CM, Barnosky A, et al. Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial. JAMA Intern Med. 2017;177(7):930-938.
- Stunkard AJ. Nutrition, aging and obesity: a critical review of a complex relationship. Int J Obes. 1983;7(3):201-20.
Image credit: John Moeses Bauan via unsplash. Image has been modified.
Motion graphics by Avocado Video
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Does Intermittent Fasting Increase Human Life Expectancy?
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Content URLDoctor's Note
Well that was interesting! I had never even heard of that study until I started digging into the topic.
There are a few more videos coming up in this fasting series. Stay tuned for:
- The 5:2 Diet and the Fasting-Mimicking Diet Put to the Test
- Time-Restricted Eating Put to the Test
- The Benefits of Early Time-Restricted Eating
All of my fasting videos can be found on the topic page.
Here are all of the previous ones if you missed any:
- The 3,500 Calorie per Pound Rule Is Wrong
- The Reason Weight Loss Plateaus When You Diet
- The New Calories per Pound of Weight Loss Rule?
- The Benefits of Calorie Restriction for Longevity
- Potential Pitfalls of Calorie Restriction
- Benefits of Fasting for Weight Loss Put to the Test
- Is Fasting Beneficial for Weight Loss?
- Is Fasting for Weight Loss Safe?
- Alternate-Day Intermittent Fasting Put to the Test
- Is Alternate-Day Intermittent Fasting Safe?
For more on longevity, check out:
- Increased Lifespan from Beans
- Fruits, Veggies, and Longevity: How Many Minutes Per Mouthful?
- The Okinawa Diet: Living to 100
- Methionine Restriction as a Life-Extension Strategy
- How to Increase Your Life Expectancy 12 to 14 Years
- How to Boost FGF21 with Diet for Longevity
- The Best Diet for Healthy Aging
If you haven’t yet, you can subscribe to my videos for free by clicking here. Read our important information about translations here.
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