I’ve been experimenting with this thing for a little over a year now.
I first started off doing it for 16 hours at a time.
I then worked up the bravery to try it for 24 and 36 hours.
Today, I wrapped on doing it for 4 days.
What is it?
The F-Word: Fasting.
Now I know, you’re probably thinking,
- “you’re crazy,”
- “don’t you feel terrible?”
- “Weren’t you irritable and angry?”
- “You’re going to go into starvation mode (whatever that means).”
- “Shouldn’t you eat every 4 hours?”
Well here’s my answer:
- No, I’m not.
- No, I actually feel the best I have in my entire life.
- No, I wasn’t irritable and angry (if you are when you’re fasting, it’s probably a combination of a personal problem and a blood sugar problem).
- No, starvation mode during fasting is a myth; think about it, if our ancestors bodies shut down when they were unable to eat for a few days, we wouldn’t be here.
- No, you definitely shouldn’t eat every 4 hours; stop listening to “Big Food.”
Fasting isn’t really a diet. It’s an un-diet.
Instead of worrying about “oh, I can’t eat that thing,” or “oh, I have to eat more of this thing — it’s high in antioxidants,” you just…don’t.
Literally, you don’t do anything.
It’s the easiest — and laziest — health and weight loss strategy that there is.
What About My Blood Sugar?
I’ll break down the metabolic process just a bit.
- Phase 1 – Feeding: Your blood sugar goes up as you absorb food. Insulin is secreted by the pancreas in order to move glucose into skeletal muscle. Excess glucose gets stored in the liver. When the liver is full, glucose gets converted to fat.
- Phase 2 – Postabsoptive: 6-24 hours after meal; Blood sugar and insulin begin to fall. The liver begins to break down glycogen, releasing glucose into the blood. These stores will last your body 24-36 hours
- Phase 3 – Gluconeogenesis: 24-48 hours after meal; glycogen — aka. sugar — runs out…and you’re not dead. The liver manufactures new glucose from amino-acids.
- Phase 4 – Ketosis: 48-72 hours after meal; Insulin has remained low, stimulating lipolysis — the breakdown of fat for energy use. Triglyceride (storage fat) is broken into glycerol and three fatty acid chains; glycerol is then used to create glycogen for the brain, saving amino acids — your precious muscles. The body uses fatty acids to create ketone bodies, supplying 75% of the brains energy.
- Phase 5 -Protein Conservation: 5 days; High levels of growth hormone maintain muscle mass and lean tissue; metabolism is supplied by fatty acids and ketones. Increased adrenaline prevents any decrease in metabolic rate.
So yes, your blood sugar will drop.
Luckily, your body is pretty savvy, and will create enough from the tissues you have in order to keep blood sugar at a baseline level.
If your diabetic, talk to your doctor about managing your medications around this process.
Why You Won’t Starve and Die
“Starvation mode” refers to the idea that your energetic processess — your metabolism — will decrease severely, and your body will “shut down” if you miss a meal or just don’t eat.
While daily caloric restriction does have a dramatic negative impact on your Basal Metabolic Rate (BMR), fasting does not.
Your metabolism actually increases during a fast.
The world record fasting was 382 days, and the patient suffered no ill effects. He started at 456 pounds and subsisted on noncaloric fluids, multivitamins, and various supplements. He ended his fast at 180 pounds, and remained at 196 pounds even 5 years later, showing little-to-no metabolic slow-down.
Contrast this with contestants of “The Biggest Loser,” who restrict calories to 70% of BMR and overexercise; who lose an average of 127 pounds, and who have a 93% failure rate.
That’s right, 93% of them have regained all of their weight after leaving the show.
Clearly, their “eat less, move more” mentality is flawed.
Wait, what?! My doctor told me to eat less and move more!
Here’s why it doesn’t seem to work:
A calorie is not a calorie. Macronutrients — glucose (carbohydrates), fats, and amino acids (protein) — are used in different ways.
- Excess glucose and fat can be stored for later use.
- Excess protein can’t be used, and is converted into glucose.
3. Your body tops off muscle glycogen stores (storage glucose) — immediate fuel available for activity. Once the muscle tanks are topped off, excess glycogen is stored in the liver.
4. Once the liver tank is topped off, excess glucose is converted into triglyceride and shuttled off to body-fat stores.
5. Unused dietary fat that is left in the blood is stored as body fat.
Unfortunately, your body prefers glucose over fat as an energy source when you’re consistently feeding.
You can’t pull from both glucose and fat stores at once. In order to access that troublesome body fat, you need to first empty the excess glycogen stores.
In other words, you’re not going to pull a steak out of the freezer to eat if you already have one, ready to eat, in the fridge.
At this point, we have to talk about a hormone you’ve probably heard a lot about. It’s your body’s Paul Revere.
“The sugar is coming!”
I’m referring to insulin.
6. Insulin is secreted from the pancreas in response to the presence of glucose, signaling the body to absorb glucose into fat, liver, and skeletal muscle tissue.
The downside of that process is that your body, while gobbling up glucose in an effort to store energy, decides to put energy burn on hold, effectively shutting off your ability to burn fat.
The more insulin yells, the less the cells listen, leading to higher concentrations of glucose in the blood without the ability to store it. This is called insulin resistance, and can lead to Type II Diabetes (T2D).
7. During fasting, your insulin levels are kept low; there being no incoming glucose.
Your cells are ready to listen when insulin gives the call.
Okay, it’s been a long road, but how does this tie to “The Biggest Loser,” and the difference between fasting and calorie restriction?
High insulin + reduced calories = metabolic slow-down
In order to burn fat, you have to:
Empty out the fridge (muscle and liver glycogen), so that you can pull fat from the freezer.
Keep insulin levels low in order to keep your body in consumption mode, limiting glucose and therefore limiting fat storage mode.
In a calorie restriction, or “eat less, move more” model, you’re eating enough to keep insulin up, and exercising enough to burn through some serious energy stores.
Unfortunately, with insulin kept high due to more frequent, albeit low-calorie feeding, your body is unable to access the freezer-fat.
Sure, you’re depleting glycogen stores in muscle and liver tissue, but with insulin present, your body is told to store everything it can get a hold of.
Thinking that there’s no energy left to use, your body initiates metabolic slow-down in order to ensure that you’re not running on empty.
It’s like your refusal to talk to that “friend” who told you that you were having a bad hair day. You know they’re there, but you refuse to interact with them. Your body knows that the fat-friend is there, but is not willing to interact with it.
Hello depressed metabolism.
Now you’ve stopped losing weight.
You’re eating the same as you did when you lost all that weight, but the scale won’t seem to budge.
Occasionally, it creeps up, but you tell yourself that’s just water weight.
Or maybe you tell yourself that it’s your genetics, and you’re doomed to stay overweight.
You quit your diet, and regain all that weight…and then some.
Why doesn’t this slow-down happen during fasting?
- Calories are low. Like, nonexistent.
- Your body depletes sugar stores within 48 hours, and has to access the fat-freezer.
- With insulin low, your body is allowed to access the fat freezer, and has the ability to access all the energy that it ever wanted.
- With access to nearly unlimited energy, there’s no reason to slow down metabolic rate. We have everything we need right here in the freezer!
Convinced? Want more?
Or perhaps your unconvinced, and you think I’m lying through my teeth.
Studies have shown that fasting every other day for twenty-two days has increased fat burning by 58%, and decreased carbohydrate burning by 53%
Other studies have shown that four days of continuous fasting — which I just wrapped up — increases BMR by 12%.
Why You Won’t Lose Your Muscles
Yes, you’ll use a little bit of muscle protein throughout your fast, especially during Phase 4. Studies, though, have shown that alternate-day fasting, eating every other day, has led to decreases in body weight and body fat without effecting lean mass (muscle and bone) at all.
During fasting, normal protein breakdown, around 75g/day, drops to 15-20g per day.
Yep, your body actually gets better at conserving muscle.
Fasting is a potent way to boost your growth hormone secretion. During fasting, your body increases adrenaline production –boosting your energy — and growth hormone production — preserving muscle mass and bone.
I could prattle on…
…but I won’t.
Sure, there are a hell of a lot of health, longevity, and cancer prevention benefits to discuss, but I’ll save that for a future post, when we both have more time.
I’ll leave you with this:
With the measuring tools I had access to, (a super fancy InBody scale and my own blood pressure device) I entered my fast at 196 pounds, 16.6% body fat, and a blood pressure of 138/82.
I exited my fast four days later at 185.6 and 14% body fat, with a blood pressure of 122/52.
Four days after that, subsisting on daily meals around 2pm when I’m hungry, and a small snack in the evening, I’m still weighing in at 186.
On top of that, I’m not really interested in food. I don’t look at it the same way.
Like alcohol, it’s an addition. A thing to be enjoyed, on occasion, within reason, but not something that I need.
Don’t get me wrong, I broke my fast with a nice juicy steak and some parmesan covered broccoli. I love it, but I don’t feel ruled by it.
I can wait to eat, and I’ll do it if, and when, I’m hungry.
I can look at cookies and chocolate and feel…indifferent. They look delicious, but I don’t need them. (If you know me, that’s a big deal. Ask my wife about eating all of the Girl Scout cookies.)
I still enjoy these things, but I don’t really need them.
Interested in giving it a shot? Perhaps your fed up with dieting and looking for something else?
Go for it.
Try the f-word.
I’m not a doctor. This is not medical advice. I’m just a nerd who likes to read research, and I figured I’d be productive by sharing it with you.
I’m a nerd, I know.
I read it so you don’t have to.
ps. If there’s anything you’re curious about, and don’t have the time, patience, or know-how to learn about it, let me know. I’ll be sure to post on it if it’s worth-while.
pps. Considerable thanks goes to Dr. Jason Fung M.D., whose book, “The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate Day, and Extended Fasting,” guided me through the process and inspired me to write this post.
images courtesy of Kaboompics, Pixabay, Scott Webb Photography.