Before I even get started on this topic I want to warn you that I am NOT a physician nor a biologist. I may be a scientist and I may understand a thing or two about medicine and biology but I don't give medical advice. I can only speak to what works for me and what has worked for others with whom I've been in contact. If you ever want to try something I mention in this blog but feel uncomfortable doing so, I would advise you either trust your gut OR get a medical doctor's opinion.
Intermittent fasting (IF) is when you go for a period of time without eating anything. That period of time can last anywhere from several hours to more than a year, as the case was with a Scottish man who fasted for 382 days. The choice is yours. Of course, if someone told me they were going to live on water and vitamins for a year I'd probably slap them on the side of their head and ask if they'd lost their mind. If you're interested in the story about this guy you can read it here: http://pmj.bmj.com/content/49/569/203.full.pdf . What impresses me the most is that he has maintained his weight loss and did not become ill. So, if you want to be monitored almost continuously, go ahead, fast for a year. Otherwise, you may wish to take a more conservative approach.
There are several different approaches to this and if you are considering it then you need to read about all four of the most common types of IF and choose the one that meets your needs as they all have different strategies and goals. I will provide links to two of them as well as links at the bottom of this post to the various medical journals, etc., that support the notion of IF.
Finally, before I really delve into the topic you need to be aware of one thing that none of the studies or anyone, really take into account is that if you are a female, your stage of life (pre-, peri-, or post-menopause) will determine if this is even a viable option for you. Well, that seems to be the case with almost anything. Yes, it does matter if you are in one stage of your life or another, and yes it does matter if you are overweight or not, and yes it does matter what your hormones are doing. Only you can determine if something is right for your body at your particular time in life.
I've written half a page and haven't even started the topic.
So, why fast? There are many health benefits associated with it, that's why, and here they are:
· FAT BURNING
Increased growth hormone factor which aids in fat loss, decreases insulin in the body and increases the body's ability to burn fat, increases insulin sensitivity thereby improving the body's fat burning mechanism, increases the levels of epinephrine and noradrenaline--two substances that activate hormone-sensitive lipase that is present in fat--and releases that fat to be used as fuel. There has also been a study that shows that for those who have binge eating issues or those who eat out of boredom, rather than true hunger, are able to stop these behaviors and will naturally decrease their caloric intake. So, for weight loss and/or getting your eating under control while sparing lean muscle mass, this is a good thing.
There aren't many studies on humans with regard to IF's ability to help cancer patients and I find it ridiculous when scientists use animal studies to provide "proof" of something that involves human health--we are, after all, not rats--but there has been a study, with humans (not a great one, but there you have it) to which I will turn.
This study involved 10 cancer patients of different genders with different types of cancer. This is what they found (I will put quotes here and citations at the bottom of the page) "patients...voluntarily fasted prior to (48-140 hours) and/or following (5-56 hours) chemotherapy. None of these patients, who received an average of 4 cycles of various chemotherapy drugs in combination with fasting, reported significant side effects caused by the fasting itself other than hunger and lightheadedness.The six patients who underwent chemotherapy with or without fasting reported a reduction in fatigue, weakness, and gastrointestinal side effects while fasting. In those patients whose cancer progression could be assessed, fasting did not prevent the chemotherapy-induced reduction of tumor volume or tumor markers."
· NEURONAL AUTOPHAGY
Just a fancy way of saying that nerve cells eat the old, tired, cells and recycle the waste, and repair themselves. I know this is an over-simplified definition and certainly not complete, but that is the gist of it. I will include links so that you can read, in-depth about this if you choose.
Without this process your brain would not develop or function the way it was meant to. Some scientists believe that Alzheimer's could be prevented or even delayed by IF. I can't really say a lot about this because the studies are mice studies and again, we aren't mice. I can only tell you what some of the possible benefits and give you the links. You can decide for yourself.
So, we have these, and a few other, benefits to IF. Should you try it? Well, that depends on what you want to believe and what your goals are.
I didn't start out doing it intentionally. It just sort of happened naturally and then I read Mark Sisson's blog posts (links at the bottom) about this process and the benefits. I can only speak to the weight-loss/maintenance side of things because that is what I know about personally and from anecdotal evidence of others. Yes, I trust anecdotal evidence from reliable sources.
The first type of IF that I want to share is called Leangains. My husband, Rudy, who is a personal fitness trainer and has about 6% body fat just naturally eats and trains this way. Neither of us had ever heard of Leangains until I started my research on IF. I know this works, even if I am at a loss to explain why. Honestly, I always worried about Rudy and his "horrible" eating style.
Rudy doesn't eat anything all day long. Then, after a very rigorous weight lifting session that will last anywhere from 1 to 2 hours, he will go another hour or so before he even thinks about eating. He normally does not eat a single bite of food until 9 or 10 PM--15 hours after getting up, and about 2 hours after working out. The thing is this--he really eats a lot when he does eat. Lots of fat (all natural fats), meat, vegetables, and fruits. Then, he eats again an hour or so later, then off to bed. Seriously, this freaked me out and I feared for his health even though he NEVER gets sick. I've known him for 13 years and he has never had a cold, the flu, or even a tummy ache. He has sickle cell and has only had two minor crises (both times when he got too cold), yet takes no pain medications--he doesn't need them, and suffers no ill effects from a disease that is fraught with pain and illness.
Well, this is essentially the Leangains method--not 100% but close. In Leangains you fast for 16 hours and then have 8 hours of feeding--typically 3 meals in 8 hours. Your workouts should take place toward the end of each fasting period. What you eat depends on what your workouts are.
You should weight train 3 days/week, always eat high protein, and on training days you should eat more carbs than fat, and on non-training days more fat and less carbs, and your meal following your workouts should have at least half of your calories for the day.
Most men have no problems with this method, but many women have said they gain FAT while doing this and others say it works fine. Again, those pesky hormones. If you are a woman and want to try it, go ahead, but if you notice that your sleep is at all interrupted or troublesome when it previously was not--stop. That is your warning that this method of IF is not right for you, so stop before you start gaining fat.
Another method is the Alternate Day fast. So, for this you stop eating at a certain time, say 11 PM on Sunday to begin your fast. You don't eat at all on Monday and then you break your fast Tuesday morning, and resume your fast on Wednesday..... I personally couldn't do this as I do endurance training on a daily basis and I need the calories from eating every day. I suppose if I were less active or downright inactive, or was worried about plaques building up in my brain, I would give it a go--but for now, nah, I'll have to take a pass. Many people, though, have reported great fat loss on this.
Then we have the Ori Hofmekler method for building big muscles. With this method you fast for 20 hours and then you have a 4 hour window in which to eat. You eat only one meal/day but you consume a huge meal. If you need a snack during the fasting period, make it small and low calorie as well as a non-protein snack. All of your protein should be eaten during your big meal.
While there are many other fasting methods I actually just use, accidentally, the Eat whenever I am hungry method. If I am hungry when I wake up, I eat. However, most days I don't eat anything until 5 or 6 PM--and I'm up at 4:30 AM and in bed by 10 PM--so that works out to about 19 or 20 hours of fasting. My fasts--again, unintentional--are normally broken with cheese, nuts, and coffee. I find this the most relaxing part of my busy days and is more of a ritual than anything. Then at about 7 PM I eat my dinner which is almost always a gigantic salad filled with a variety of fresh, brightly colored veggies, sometimes mandarin orange segments too, 6 to 8 ounces of chicken breast, and a very creamy dressing. Other times, it's something like pork and pumpkin plus a green vegetable. The thing is, these meals are usually very high in fat, moderate in protein, and low in carbs.
This way of eating took a long time to come about. I used to binge eat or eat when I was bored. I rarely, if ever, do that any longer. Is it because I accidentally fasted? I don't know, but there are others who have said the same for themselves.
I have no problems with my daily long runs or my TRX training--in fact, I do better when I don't eat just before or just after my exercise. I usually feel very energized throughout the day and other people who do this report the same thing.
The only other thing I really want to emphasize is this: If you are NOT fat adapted, meaning you have been paleo or low carb long enough such that your body naturally burns fat for fuel first, it will be very difficult to go such long periods without eating. As you progress more with this lifestyle your body will function better and become more efficient with fat burning and your periods of hunger will just naturally be spaced apart further and further. You'll know when you are fat adapted, but the only way to do that is to limit the amount of carbohydrates and the type of carbohydrates that you eat during the day.
So, try a short fasting period and then gradually increase the amount of time before eating--but ONLY if you are not hungry. If you start to feel ravenously hungry but still have 2 hours before your planned meal, eat anyway and forget the schedule. Your body will let you know and you should listen to your body.
Oh, something else that I found interesting is that people who have done the Atkins diet more than once sometimes have a hard time losing when going back to a lower carb diet (50-100g/day for weight loss) have benefited from doing these types of fasts and have regained their ability to lose on a lower carb diet.
By the way, I am a 50-something, peri-menopausal woman and my experiences may be different than yours, whether you are male or female.
Now, if you want to read some of the studies, or if you just want to read someone's summaries of these studies (remember, I don't believe in reinventing the wheel), here are the links. Personally, I would go to the first one, Mark's Daily Apple. He goes into a lot more depth than I have and has tons more studies spaced out over 7 different articles. If you browse to the end of each article there is a menu with links to the others. Enjoy!
So, until Monday when we'll look at the glycemic index and the glycemic load: facts, misconceptions, and downright lies.