Health & Wellbeing

Review of intermittent fasting research suggests broad health benefits

Review of intermittent fasting research suggests broad health benefits
A new analysis of current intermittent fasting research suggests the dietary strategy could soon be incorporated as standard medical health and diet advice
A new analysis of current intermittent fasting research suggests the dietary strategy could soon be incorporated as standard medical health and diet advice
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A new analysis of current intermittent fasting research suggests the dietary strategy could soon be incorporated as standard medical health and diet advice
A new analysis of current intermittent fasting research suggests the dietary strategy could soon be incorporated as standard medical health and diet advice
Some of the health benefits of intermittent fasting cited in the new review article
Some of the health benefits of intermittent fasting cited in the new review article

A newly published review article in The New England Journal Of Medicine has examined an array of current research on intermittent fasting, from animal studies to human clinical trials. The review clarifies different fasting regimes while also outlining a variety of health benefits the eating strategies can confer in humans.

Although intermittent fasting is currently a bit of a dietary trend, scientists have been investigating the effects of irregular caloric intakes in animals for several decades. Mark Mattson, an author on the new review and neuroscientist from Johns Hopkins University, explains one of the key processes triggered by intermittent fasting is called metabolic switching.

When an organism is starved of food it shifts how it produces energy, switching from readily accessible glucose in consumed food to a process called ketogenesis, whereby molecules called ketone bodies are produced though the conversion of fat stores. This energy production shift is dubbed metabolic switching, and Mattson’s review article suggests frequent shifts between the two metabolic states can result in an array of health benefits.

“Periodic flipping of the metabolic switch not only provides the ketones that are necessary to fuel cells during the fasting period but also elicits highly orchestrated systemic and cellular responses that carry over into the fed state to bolster mental and physical performance, as well as disease resistance,” write Mattson and co-author Rafael de Cabo.

Some of the health benefits of intermittent fasting cited in the new review article
Some of the health benefits of intermittent fasting cited in the new review article

The review breaks intermittent fasting into two general categories: alternate day fasting and time-restricted feeding. Alternate day fasting involves significant caloric restriction on one day or more each week – the modern 5:2 eating regime is a variation on alternate day fasting. Time restricted feeding, on the other hand, involves fasting for a period within the 24-hour cycle – this category would include the common 16:8 regime, which restricts all caloric intake to a period of no more than eight hours in a given 24-hour period.

What is the ideal intermittent fasting regime? That is still unclear. The article notes that ketone bodies have been found to begin rising in humans within eight to 12 hours of fasting, suggesting time-restricted feeding methods could be effective in harnessing the health benefits of metabolic switching. So 16 hours of fasting every day may be an easy way to implement a form of intermittent fasting. A recent study has even suggested dropping that fasting period down to 14 hours a day confers health benefits.

Mattson and de Cabo suggest in the review article that physicians incorporate intermittent fasting dietary strategies into treatment regimes for patients at risk of everything from dementia to cardiovascular disease. And, understanding the challenges patients have in maintaining these kinds of dietary interventions, the article describes gradually increasing fasting periods over a number of months as the most effective way to deploy such dietary changes.

So, for example, the article suggests for the first month’s intervention a patient only drop to either 10-hour feeding a day for five days a week, or 1,000 calories in total one day per week. Gradually over several months this intervention would transition, so by month four the patient reaches either a complete time restricted feeding regime eating only six hours a day every day, or a 5:2 regime of no more than 500 calories for two days every week.

“Patients should be advised that feeling hungry and irritable is common initially and usually passes after two weeks to a month as the body and brain become accustomed to the new habit,” Mattson explains.

The review article does stress there is much still to be explored in terms of the long-term effects of intermittent fasting and in understanding the biological mechanisms that may be at play. However, it does seem increasingly clear that our current culture of always available food, and near constant snacking, is not necessarily the best way to feed. And, while there is still more research needed before broad conclusions and recommendations can be made, Mattson is confident we are close to a point where intermittent fasting regimes could be incorporated into popular health advice.

“We are at a transition point where we could soon consider adding information about intermittent fasting to medical school curricula alongside standard advice about healthy diets and exercise,” Mattson concludes.

The new review article was published in The New England Journal of Medicine.

Source: Johns Hopkins Medicine

I have tried similar versions of intermittent fasting, the 5:2 and the 16:8. It's not easy, especially since it's difficult for me to fall asleep on an empty stomach. It's quite possible that success with this method would be more achievable if there's someone helping you to stay on track with your regimen.
A few years ago I was in an ideal situation to try fasting. I used the 5:2 technique, electing to eat less than 500 calories on Mondays and Tuesdays. I rode a bicycle to my office, 4 miles each morning, and rode home energetically the 'long' way, 13 miles each evening. My weight dropped from 185 to 160 over a four month period. I did not notice any hunger pangs but the cycling probably contributed to that. A return to a more traditional lifestyle has seen my weight return to 180 over the four years since then. I plan to renew my fasting and cycling regime.

Meanwhile, my wife adopted a 16:8 hour daily fasting routine. Over several years her weight has dropped from 160 to around 112. She works out several times a week but not especially strenuously, mostly just walking or dancing. She is probably fitter now in her 70s than she has ever been since I first knew her in her teens, when she weighed around 132 as captain of her school swim team.

As an engineer I tend to be detail oriented, track progress and keep records. I'm convinced fasting is beneficial and easy to adopt. When I started my routine I ate mostly packaged frozen meals with stated calorie content so it was easy to keep score. It also encouraged me to eat modest portions of healthy foods. I also found that eating cake or ice cream on non fasting days had no obvious negative impact. When I over fasted I found I became tired but just eating more corrected that while not causing any weight gains.
For anyone who wants to try the 16/8 fasting method here's what I've been doing for about two months with great success: I eat only from 2PM until 8PM (I'm on a somewhat more limited 18/6 fasting schedule) and I go to sleep at 10PM which means I never go to bed hungry. It's working very well for me. I've lost weight instead of gradually gaining. I'm usually hungry when I wake up, but I just take a sip of water every time I think about food, and as long as I keep my mind and/or body active until 2PM I can easily "not eat" until then. I chose this fasting method because I can do it every day without changing the foods I normally eat. This was important to me because if I had to change my diet I would probably not stick to it. I would never try to measure my caloric intake or calculate how many calories each food I eat provides, and fortunately this fasting method eliminates these issues completely.
Kyril Mocine
I really want this to be true.
But why do we see so much internet writing saying essentially 'Skipping breakfast BAD!".
Am I misunderstanding something - Is 16:8 not, in essence, the same as skipping breakfast, and just having lunch and dinner?"
Hoping to hear from experts - would appreciate any insight!
One of my neighbors lost a lot of unwanted weight. I asked and he said the only method that worked for him was fasting, so I tried it.
I'm 68 years old, 6 foot even, was at 240 pounds. Not obese but definitely not health. His method for quick weight loss was 1 day of eating, one day of fasting. I tried that and in 6 months was in the 190's, which I have not been since college. The hardest part was the psychology of fasting; the snacks at night were (and still are) my downfall when I fail to fast. I find that after the day of fasting, the second day is much easier. I do not take my fasts past 48 hours, although I think I could easier than I thought. On days I eat, I only eat a sandwich at night, usually a very healthy sandwich like a bahn mi. When I got to 190, I started just eating only the bahn mi on a daily basis and the weight stayed relatively stable. I have not seen any memory gains, but do feel much more healthy.
Remember that there were no obese Neanderthals or primitive hunter gatherer that were fat, basically, because their way of life could not be abundant: they ate when they found food and that means they could go on days without food (in the worst cases).
Skip to modern times, there is an over abundance of easily accessible food everywhere. Just turn around or go to that other room, there will be some sort of snack... Office space ? Vending machines are there to screw you. Office parties ? Good golly ! Now, go on youtube or amazon prime and check for the movie "The Science Of Fasting" - it really works but granted, it's very difficult to stick to a long fasting habit (like the Neanderthals) so nowadays, we've been trying to dial in on a "magic formula" if you will, that people can follow. And that magic could be something to happen on a daily basis, but if you have people around sabotaging your efforts - think "going out for dinner" ....
Works well for me - I'm a fan.
Just a normal lunch at noon, and a normal dinner at 7-ish. No snacks; lots of black coffee for breakfast is fine.
Down 35 in 6 months (started in June at 6'0 and 227; around 192 before Thanksgiving). No other changes; don't exercise at 56!
Global Genius
I have very successfully done for a months a time 23:1 fasting. That is one single keto meal a day. For example, a large portion of fat, bacon, 4-6 eggs with plenty of cheese. The health results are awesome, more muscle, lots of more energy; in my case like 100X more energy, for example I now can do twenty miles hikes with no problem. For me it was not about weight lost, it was about gaining better health.
Jim Witherspoon
I've been doing alternate day fasting since September, and I am now at my goal weight of 160. It's so simple, no mental effort required. I feel good during my fasting day, drinking water will stave off the worst of any hunger symptoms. Great feeling of accomplishment the next morning! So great to be able to eat a normal "maintenance level" of calories, or even more, during my "eating window". Now that I am at my goal weight, I'll continue to fast as a "maintenance" method, because in the past I've always gained a lot of weight back after "dieting". Lately I'm not strict on fasting every other day - I just throw in "fast days" when I think I need one.
akarp even obvious in the names. 'Breakfast' should literally be 'breaking our fast'.