An extreme technique called alternate-day fasting can lead to very fast weight loss, new research finds.
Alternate-day fasting involves eating freely one day, followed by a day of fasting.
On fasting days, only water or unsweetened tea or coffee is allowed.
After just four weeks, people in the study lost an average of almost 8 pounds.
This meant they lost an average of 4.5 percent of their body weight.
The alternate-day diet also had a range of other benefits, including reduced belly fat, lower cholesterol and reduced levels of biological markers linked to aging, disease and inflammation.
Dr Thomas Pieber, study co-author, said:
“Why exactly calorie restriction and fasting induce so many beneficial effects is not fully clear yet.
The elegant thing about strict ADF [alternate-day fasting] is that it doesn’t require participants to count their meals and calories: they just don’t eat anything for one day.”
For the study, 30 healthy people of normal weight went on the ADF diet for four weeks.
A comparison group of 30 people could eat whatever they wanted.
Professor Harald Sourij, study co-author, explained the results:
“We found that on average, during the 12 hours when they could eat normally, the participants in the ADF group compensated for some of the calories lost from the fasting, but not all.
Overall, they reached a mean calorie restriction of about 35% and lost an average of 3.5 kg [7.7 lb] during four weeks of ADF.”
People with viral infections, though, should not fast, said Professor Frank Madeo, study co-author:
“We feel that it is a good regime for some months for obese people to cut weight, or it might even be a useful clinical intervention in diseases driven by inflammation.
However, further research is needed before it can be applied in daily practice.
Additionally, we advise people not to fast if they have a viral infection, because the immune system probably requires immediate energy to fight viruses.
Hence, it is important to consult a doctor before any harsh dietary regime is undertaken.”
About the author
Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology.
He has been writing about scientific research on PsyBlog since 2004. He is also the author of the book “Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks:
- Accept Yourself: How to feel a profound sense of warmth and self-compassion
- The Anxiety Plan: 42 Strategies For Worry, Phobias, OCD and Panic
- Spark: 17 Steps That Will Boost Your Motivation For Anything
- Activate: How To Find Joy Again By Changing What You Do
The study was published in the journal Cell Metabolism (Stekovic et al., 2019).