Here’s the obligatory medical warning: You should not start this or any diet or exercise program without consulting your doctor. I am not a doctor, and nothing in here constitutes medical advice.
It bucks most current dietary advice. We’re told that dieting for weight control consists of a calorie restricted diet where you eat a ton of small meals a day. There’s a whole host of science that shows that thinking is wrong – not to mention the fact that American’s have been dieting like that for decades.
Calories in vs. calories out needs to die in a fire.
There’s a secret reason why the calories in, calories out model of weight loss doesn’t work. Are you ready? The human body doesn’t use calories for fuel. The human body uses different chemical processes to create the energy it needs from various sources, whether from the food you just consumed, your fat stores or from glycogen stored in your liver.
The human body is not a simple machine; it’s continuously storing fuel, releasing fuel. The fuel it uses depends entirely upon your hormonal state. It’s pretty complicated, but the main player here is insulin. Eat enough throughout the day, and you can develop insulin resistance or type II diabetes.
In general, if you don’t have some metabolic condition, you want to keep insulin low. Insulin makes your body store fat. Different foods release insulin in a variety of ways – carbs release it faster, while fats are the slowest. This is why high-fat low-carb diets like ketogenic diets work – they are controlling insulin release.
Anything you eat, however, even a tiny amount of fat, protein, or carbohydrate, is going to cause your body to release insulin. This is one of the reasons intermittent fasting has become so popular.
What Is Intermittent Fasting?
Intermittent fasting is just like what it sounds. You stop eating for some period repeatedly. There are various ways to do this. One of the simplest ways is to restrict your eating to an 8-hour window each day. This leaves your body in a fasting state for 16 hours.
Intermittent fasting is the real Paleo. It’s the way our ancestors ate. We came from hunter/gatherers. Three meals a day and two snacks are a modern invention.
But Fasting is Terrible for Reasons, Right?
Modern dietary advice might tell you that fasting is going to slow your metabolism. The science shows that intermittent fasting increases basal metabolic rate – the amount of energy you use just from existing each day.
On the other hand, caloric restriction, like with most modern diets, actually does slow down your basal metabolic rate. This makes maintaining any kind of weight loss next to impossible. In a study of contestants on the weight loss reality TV show, The Biggest Loser, only one contestant managed to keep the weight off. One of the winners had a metabolic rate 800 calories a day lower than when he started. The dieting from that show devastated his metabolism.
You’ll never see a Biggest Loser reunion show.
Another common misconception is that fasting makes you lose muscle mass. This is not true. Fasting spares lean body mass. Again think of the hunter/gatherers. If they lost their muscle mass when fasted – they wouldn’t be able to hunt. Our bodies aren’t made that way. In fact, some of the processes that fasting trigger might be helpful for building muscle mass.
Lastly, a lot of people think that fasting will make them sluggish and tired. That’s just not true. It may happen a little in the beginning as your body switches fuel systems, but fasting is great for energy level and cognition. The brain gets fed its preferred fuel, and its cells can clean out the gunk. I’ll talk more about brain effects below.
Why Would You Want To Try Intermittent Fasting?
There are many health benefits to intermittent fasting, here are a few:
Intermittent fasting is a great way to turn up your metabolism and control insulin – helping tremendously with weight loss. It spares lean mass while burning predominantly fat for fuel.
Intermittent fasting can be combined with almost any other method of eating – vegan, paleo, keto. You can, and probably will be, restricting calories on a fast – but that won’t cause the metabolic problems of normally restricted calorie dieting.
Extreme calorie restriction and fasting have both shown promising results for longevity. Studies on fasting have shown massive increases in the release of grown hormone and testosterone in men.
Fasting has also been shown to reduce C-Reactive proteins, inflammatory markers in the bloodstream. Inflammation is implicated in everything from depression to arthritis.
One of the processes supported by fasting is called autophagy. Autophagy is where your cells kill off and consume their worn out parts. It sounds gross, but it is a critical process to prevent things like Alzheimer’s and certain cancers.
Fasting naturally decreases insulin resistance. Insulin resistance is strongly linked to metabolic syndrome. Metabolic syndrome is a cluster of things like high blood pressure, cholesterol, and blood sugar, and increased abdominal fat. These things increase the risk of heart attack, stroke, and other severe health crises.
Brain Health and Smarts
Supporting autophagy helps prevent Alzheimer’s, but it can also increase neuroplasticity. Besides Renewing the brain makes it more efficient at creating new pathways. There is also research that shows that fasting just two times per week can lower the risk of Parkinson’s.
According to a neuroscientist, Mark Mattson, from the National Institute on Aging, fasting improves cognitive function, increases stress resistance, reduces inflammation, and increases the production of proteins in the brain which grows and strengthens the connection between neurons. He also states that fasting may help grow new nerve cells from your stem cells.
Anecdotally, I feel sharper when I fast. Once more consider our ancestors. If their minds got dull when they hadn’t eaten in a couple of days, they wouldn’t be able to catch food, and they would die. You and I wouldn’t be here.
OK, So I Want to Try Fasting
Intermittent fasting is a stress on your body, and it’s certainly not appropriate for some people. Check with your Doctor – get your bloodwork done.
I recommend checking out the work of Dr. Jason Fung. You can find a lot of video of him for free on YouTube and other sites. He breaks down the science of IF so that anybody can understand it. He also has a couple of great books, available on Amazon.