The 16/8 Intermittent Fasting System: What and Why?
When facing disease, inflammation and/or weight gain, most people start to plan what they are going to eat in an effort to achieve greater health. But knowing not only what to eat but when to eat is equally important. Intermittent Fasting is a strategy for planning the timing of eating.
When people ask, why fast? Why deliberately starve yourself? First, I tell them that periods of eating and fasting are natural for the human body, just like periods of activity and rest. The body functions better with a balance of both.
I also like to tell them that fasting does not equate to excess hunger or “starving yourself”. People who practice intermittent fasting quickly come to realize that mild feelings of hunger are normal and they pass. The longer you do intermittent fasting, the more adapted you become and hunger comes in mild waves. People who fast learn to trust that the wave will pass and they can make it through another hour or two, sometimes longer until their eating window or when they have time to eat.
The final thing I like to say is, do you ask a runner or jogger why they run if nothing is chasing them? No, you wouldn’t ask them that because it is clear that the runner is using his activity as a strategy for health. It is the same with fasting. Fasting is a strategy for health.
You become more “insulin sensitive” when you fast. This is because you are not overusing insulin all the time to constantly push sugar into the cells. Your body, your pancreas, your cells are getting a break. If you are using insulin all the time in a chronic fashion, your body no longer responds– this is desensitization. Because insulin is a hormone, it is supposed to be pulsatile, not continuous. The continuous/chronic production of insulin is the cause of high blood sugar. The insulin can no longer push the sugar into the cells.
Insulin itself also has a toxic effect when in chronic use and will lead to inflammation. Again, this is because insulin is a hormone and meant to be pulsatile. So when insulin production goes on chronically for years, the body’s adaptive mechanism is to become insulin resistant. The body is resisting the overload.
Time is a crucial component because you only become diabetic and inflamed due to chronic production of and exposure to insulin over time. This is why the prediabetic state takes about 13 years to manifest.
As time goes on and exposure goes on with it, the body’s insulin stops being able to push sugar (glucose) into cells, sugar spills out into the bloodstream and into tissues. Over time, diabetics experience wounds that won’t heal and chronic infections. This is because there is sugar filling up all the extra spaces. It’s looking for a place to go since it cannot fit into the cells anymore.
Intermittent Fasting is a fancy way to say “I strategically plan the timing of when I eat.” A simple way to understand this is to know that when you are in a fasted state, insulin is low. When you are in a non-fasted state, insulin is high (as long as you are eating carbs but more on that later).
This is why your doctor asks you to fast when you get a blood sugar test. They want to see if sugar is still hanging around the bloodstream after many hours (8-12 hours). If sugar is high this means insulin can’t do its job because the body’s cell will no longer accept glucose. The receptors on the cells are not working because the cell is already too full, like a suitcase that has been filled with too many clothes. The suitcase is at maximum capacity. The latches are broken and clothes are spilling out onto the floor.
Benefits of Fasting Extend Beyond A Healthy Insulin Response
Aside from balancing out the insulin response, fasting is good for inflammation and autoimmune diseases. In a fasted state, the body increases all cellular “housekeeping.” It cleans up debris, repairs cells and “resets” the immune system. People who fast live longer, have less cancer, cardiovascular disease risk and dementia.
Where to start: The 16-8 Method
There are many ways to fast. You can fast for hours, days, or weeks. But the easiest way for people to start fasting is by implementing a 16:8. This is when you decide on an 8 hour “eating window” and the rest of the time (16 hours), you are fasting.
Examples of eating windows:
The window you choose may vary depending on what works for your schedule. I ask people to leave a 3-hour time frame between bed and dinner. So if you finish dinner at 7pm, you are asleep by 10pm, then the next day you don’t eat until 11am. You have fasted for 16 hours.
Water, tea and coffee are all allowed outside of the eating window. Sugar and creamers/cream, etc.. are not allowed. If you absolutely need something in your coffee, in the beginning days of you fast, you can use a fat source like whole cream (not ½ and ½ but whole cream that has all the fat) or butter. If you use whole cream or butter, it is not a “true” fast but it is still going to help you get into fat burning mode because it will not cause a large spike in insulin. However, as you get used to fasting, you will transition to black tea or coffee for your morning beverage so you can get the full benefits of a true fast.
Fasting Allows for More Flexible Eating
Fasting is a tool and it is flexible. Because you are spending more time in a fat-burning (low insulin) state, you can be a bit more flexible in your eating window. That said, for people with a lot of inflammation, weight gain, diabetes or pre-diabetes, you will likely need to stay relatively low-carb or keto in your eating window.
Fasting can be used as a “delay, don’t deny” strategy. I do recommend that people stick to healthy foods as much as possible in their eating window. That said, fasting is a handy tool after a weekend of social gatherings where food was maybe a little bit too abundant!
Fasting is Not Calorie Restriction
Calorie restricted diets work short-term for weight loss because you are reducing energy input for a time being. The problem is the body adapts and will slow down metabolism to compensate. This can damage your metabolism if done chronically and people end up gaining more weight even if they continue to “diet” (calorie restrict) and exercise.
Fasting won’t damage your metabolism because you are not calorie restricting, you are just timing your eating in a strategic way. You are deliberately spending a longer period of time with low insulin. You will not worry about or track calories while you fast.
Most people will be doing a low-carb or Keto diet. You will focus on getting in a lot of good fats and protein. This will be your primary source of fuel.
The Body Runs on a Hybrid Engine
Human physiology is very intelligent. It developed a dual engine system where the body can burn two types of fuel sources- sugar or fat. This is why you don’t perish in the middle of the night if you don’t eat a banana. Glucose goes down, insulin goes down and another hormone called glucagon goes up. Fat burning begins.
Insulin and Glucagon are opposites, yin and yang. Two sides of a seesaw. When fasting insulin is low, glucagon is high. Glucagon=fat burn. People begin to lose weight. If you do a very restricted carb diet with intermittent fasting, you will go into ketosis. This is when the body is fully immersed in fat burning mode and the brain begins to utilize ketones as a fuel. Hunger is also suppressed.
Fasting is Normal
The body was built to fast. We evolved over millennia for times of feast or famine. We store energy effectively and efficiently. In modern times, we rarely experience times of famine or even scarcity through the seasons. Winter was normally a time where food was scarce and we would lived off of body fat stores that had increased during summer and fall harvest.
But the benefits of our ability to fast extend beyond just keeping us alive. When we burn fat stores, we produce less oxidative stress, cells repair and we are in a heightened mental state. It has been postulated that some of the cognitive sharpness that occurs during fasting is a biological adaptation. You have to be clear, sharp and quick to hunt prey. You often will be hunting prey when you are hungry (fasted).
Most People Are Doing An 8:16
Hunter gatherers were definitely fat-burners. They didn’t need a snack every 2-4 hours to “keep their blood sugar stable”. This would have been detrimental to survival. It has only been the past 40 years where we have emphasized high carb breakfasts (cereal, toast), consistent snacking and carbohydrates at every meal. The low-fat craze of the 80s and 90s deepened this habit.
Most people are doing an 8:16. They are fasting for 8 hours and eating for 16. We just need to start out by reversing these time frames.
Hunter gatherers were not glucose dependent. They did not fall over in the bush after 3 hours in a fit of hunger or “low blood sugar” and need a snickers bar so they could push through the rest of their hunt. They sustained mental clarity and energy just on their own fat stores.
Glucose dependence is when your body is so used to the insulin-glucose engine system, it cannot switch over to the glucagon-fat-burning engine very quickly or effectively (yet). The result of this lack of efficiency is when blood sugar gets low, the person gets cranky, shaky, nauseous and very hungry. This phenomenon keeps some people glucose dependent because they reach for food the moment they feel these symptoms.
The irony of it is that if they pushed through, drank some electrolyte water (no sugar of course) and ate more fat and protein at their main meals, within a couple of weeks they would start switching easily into fat-burning and would no longer experience these extreme dips.
For healthy people who want to lose some weight
It depends on how much weight you would like to lose. If you are still glucose dependent and not doing keto, starting with a 16:8, 3-7 days a week is reasonable. After 2 weeks, you can shrink the eating window so you are doing a 18:6 or even a 20:4. Some people can easily transition to a 22:2. When you shrink your window you can go to 3 days a week and do a 16:8 the rest of the week.
Make sure to eat enough during your eating window. Again, this is not calorie restriction or calorie counting!
For those who need to lose weight and also have diabetes or other types of inflammation (autoimmunity, etc..)
First off, you should be under the care of a knowledgeable clinician who is trained in dietary management of your particular disease.
Second, everyone is different and has different needs, even those with the same diagnosis or disorder. You should be under the care of a clinician who has done a full intake and review of your systems. Preferably, a team of clinicians who are playing nice with each other and coordinating your care.
That said, most people will follow similar guidelines above but you will check in with your clinician more often. These folks usually need to adhere to some version of a Low-Carb lifestyle. I also recommend to keep track of blood glucose by testing in the morning and 90-120 minutes after meals.
No, Not Everyone Should Be Fasting
Some people should not fast. This includes pregnant and/or breastfeeding women, people over 70 years old (there are exceptions), and people with certain chronic illness. Always, without exception, check with a clinician who is experienced in using fasting as a strategy before you embark on on this lifestyle. It is effective, but like all lifestyle interventions, you must know how to do it correctly and safely in order to get the full benefits!
If you have any questions about Intermittent Fasting, please schedule your free consultation today!