Fasting Twice A Week Might Boost Brain Health, But It’s Still Not A Smart Idea

Scientists are reporting that fasting one or two days a week can boost your brain health and increase longevity. While that sounds like a good recipe for an eating disorder, there are better ways to make sure your diet is good for the brain and body than starving yourself every few days.

The study comes from the National Institute on Ageing, where researchers looked at whether intermittent fasting—eating no more than 500 calories per day, one or two days per week—could help protect the brain against Alzheimer’s, Parkinson’s and other degenerative diseases. The results in both animals and humans so far have been promising.

That’s not surprising. Earlier this month, Mayo Clinic researchers reported that overeating can double the risk of memory loss in older adults. There’s increasing evidence of links between obesity, diabetes and dementia, and that things like trans fats can cause brain shrinkage. Conversely, the effects of a low-calorie diet on longevity and brain health are well known. Rats and mice on calorie-restricted diets have increased their lifespan by up to 40%. And calorie restriction—known as CR among devotees and researchers—has gained an intense human following and spawned popular books like The Longevity Diet.

But consistently keeping caloric intake low is something not a lot of people have the desire or willpower to do—which is why NIA researchers want to see whether regular, short-term bursts of CR could have the same effect. Or maybe it could work even better. Mark Mattson, head of the NIA’s neuroscience laboratory, thinks overall calorie restriction “is not likely to be the best method of triggering” brain protection.

“It is likely to be better to go on intermittent bouts of fasting, in which you eat hardly anything at all, and then have periods when you eat as much as you want,” he said. “In other words, timing appears to be a crucial element to this process.”

Mattson also said intermittent fasting would be easier for people—knowing that after a day with little or no food they could eat as much as they wanted the next day—than cutting back on calories overall. Really? Twice-weekly fasting seems like a less tenable plan than overall CR to me. People following a calorie restricted diet (1,200-1,400 calories per day) all the time get used to it. Their bodies get used to needing less calories. They figure out ways to still get all the nutrients they need while eating less food, ways to cook, eat and feel full that are nutritious but low-calorie.

In order to do calorie restriction successfully and healthily, it takes a total dietary overhaul—the kind which you can’t learn fasting twice a week and then eating as much as and whatever you want the rest of the time. If your body doesn’t get used to an overall decrease in caloric intake, aren’t you likely to compensate for the fasting days by eating more/worse on non-fasting days? And to feel incredibly hungry and grumpy when you do fast? Maybe I just don’t get it (I’m no neuroscientist), but it doesn’t seem like something that would work well for many people outside a laboratory setting.

It does, however, seem like a recipe for creating disordered eaters. Starve yourself twice a week, eat as much as you want other times? That’s sure to inspire a really healthy relationship with food.

As the UK Alzheimer’s Society told the Huffington Post: ”The best way to cut down your chances of developing dementia is to combine a balanced diet with regular exercise, not smoking, and getting your blood pressure and cholesterol regularly checked.”

I think all the research on the interplay of diet, brain health and longevity is fascinating (and important). I may even become a total CR nut someday. But this periodic fasting scheme just seems dangerous and silly. It’s exactly the kind of magic bullet approach we love—do this one straightforward thing and then you can keep doing everything else the same and still lose weight/stay healthy/not die!

Eating for health requires an overall commitment. The upside is that cutting back on processed foods and eating a diet high in Omega-3′s, fruits, vegetables and whole grains can also boost or extend your brain’s health—and you don’t have to live like an ascetic or a bulimic teenager to do it.


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    • Wayne Daniels

      Going without food for a day is not starving yourself! We are designed to survive long periods without eating.Do some research.

      • Bunny Walker

        Thank you! I was just about to chime in with that! I’m beginning to get frustrated with this website’s bloggers for their alacrity to decry things as gateways to eating disorders.

      • HonkyTonks

        “Not a good idea” – according to you. There are many people who are quite happy to practice intermittent fasting, and don’t have issues with eating. Look into it.

    • 2 Meal Mike

      “Starve yourself” seems to be a term used more in response to ideas that contradict past assumptions about healthy eating (eat all day, small snacks, etc). I once preached that line about more meal too as a trainer, till I did my own research and started to listen to my own body.

      Science (and people) has shown that eating less often may be a more sustainable way to lose weight, keep it off, enjoy doing it and also still make the right food choices. The body works in long term scenarios over time, not meal to meal. It compensates and balances out. It spares muscles. It regulates metabolism accordingly.

      This is a good place to start to understand that the role of metabolism and meal frequency is more complex than just skipping a meal:

      If you eat 500 calories a day, that is not the same as someone who skips a meal (intermittently fasts) and still eats enough overall. If you eat junk food after fasting all the time, you probably won’t lose weight. If people have past issues with eating disorders, this way will probably not work well with them (unless they can embrace eating bigger healthier meals).

      Most of what is told out there is loosely based on some singled out facts, but passed down really as opinion. In the end, I’ll go with eating less and enjoying what I eat more. If that’s starvation…then I’ve been starving myself for the last 6 or so years and enjoy every minute of it.

    • Jenn

      As someone who suffers from disordered eating, I resent the “eating disorder” label being tossed around. Fasting is not an eating disorder. As someone who is prone to disordered eating, I would be hesitant to fast, as it might be triggering, BUT a person with a healthy attitude towards food can absolutely benefit from fasting occasionally, as the idea is that the body just doesn’t need as much food as we give it in our society of abundance, rather than thinking about it as “this means I get to eat whatever I want later.”

    • John

      Uninformed opinionated writing makes for poor journalism, blog or otherwise.

    • W. Ying

      Yes, it is right.
      Our ancestors just did that way in the wild nature 10,000 years ago.
      So, our DNA adapt it well.

    • Jennifer

      Actually, it’s way more livable than counting and restricting your calories every single day. Fasting twice a week helped me tremendously, and actually has helped me become aware of when I’m really hungry on eating days. Also, it’s not recommended to eating everything you want on non-fasting days. You eat sensibly without being neurotic about counting calories the rest of the week, and then fasting for two 24 hour periods when it’s convenient.

    • Pema Wangchug

      I’m a very active 24 year old man who exercises (boxing, Lifitng weights, Aerobics, and Running) 6 days a week. I started the 24 hour fast protocol (twice a week) for 2 weeks now, and I feel great! You really feel atuned to your body and I’m already seeing results. Please do more research before making such opinionated and unsubstantiated claims.

    • Luke

      I do this, and it seems fine to me. Your point about making up for it and overeating on the normal days, in my case, is untrue. I actually found that I ate less than I normally did (because I used to overeat) on the non-fast days. I also, found that I ate very healthy food on the fast days, because you still want to eat enough to keep you going, so you ensure that you are eating low calorie foods, such as fruit and veg. I found after the first 2 weeks that my energy levels were increased, I was eating healthier all week round and losing weight. It might not be for everyone, but I prefer this than the idea of eating only 1200-1500 calories everyday, that sounds like hell, having to watch it every single day.
      Come to think of it, this whole article just seems like it is the opinions of 1 person who hasn’t actually bothered to even try it to see or even speak to someone who has, but just judged it on their uneducated preconceptions. I think I may have just wasted 10 minutes of my life.