Does Intermittent Fasting Actually Work?
What is Intermittent Fasting?
Intermittent fasting or "Time Restricted Eating" is an eating plan where you have a window of time that you don't eat, and then you have a smaller window of time that you do eat.
There's several ways of doing this. Some of these include:
"1 Meal a day"
Alternate day fasting
Fasting once a week
Cycled during a 24 hour time frame - Most common
Fast 16-20 hours, 4-8 hour eating window
Before we move on, I think it's important to say that intermittent fasting is NOT a form of starvation. Your body is using stored up nutrients to keep your body going. When you starve or enter into a period of starvation, you run OUT of that stored energy in your body and begin to break down vital things like organs. So, just a point of clarification.
Science of Intermittent Fasting - Fed and Fasted States
Fed State or whenever you eat food
Your body breaks down food into glucose, which is the main energy source for your body.
Anything left over is transformed into "storage forms of energy". There are 2 main forms of stored energy in your body. They are:
Glycogen, which is stored in the liver
Fats, which are stored in the adipose tissue
Fasted Stated or whenever you don't eat food for a prolonged period of time
1st:
Glycogen—> glucose
On average it takes about 10-20 hours to fully use these glycogen stores. However, if you're ACTIVE, you use up your glycogen reserves MUCH more quickly. Once the glycogen storages are depleted, the body taps into those energy stores in the adipose tissues (fats).
2nd:
Adipose Tissue—> ketones
These fats are converted into ketones in the liver via the process of Beta Oxidation (whoa..big fancy word). The name's not important. These ketones are used throughout the body for additional metabolic fuel
So, a quick recap of the fasted state. Whenever you don't eat something for a long period of time, you body will FIRST burn through your glycogen stores in your liver. When those run out, your body then burns fat in order for you to get sufficient energy.
However, there is a final point I'd like to make. In the fasted state, particularly during periods of prolonged exercise, your body will also break down muscle tissue into amino acids (the building blocks of proteins) and use those for energy as well. The mechanism of this isn't important but the concept is. This is why it is essential to replenish these amino acids by eating enough protein during your eating time frames, so your body doesn't have to keep breaking down your muscles.
Benefits
So I will say right off the bat that MOST of the super beneficial things about intermittent fasting that we've seen has been primarily only in rats. However, the results are good!J ust a quick summary on one of the major studies: they took a bunch of rats and didn't let them eat for 16 hours, and then the other 8 hours they let them eat WHATEVER they wanted. The end result: none of the rats could really gain weight. They also found in the period of not eating, these rats up-regulated liver enzymes that are responsible for fat metabolism.
These rats became extremely efficient at burning fat
It’s important to understand that a 16 hour fast to a rat is NOT the same for 16 hours for humans as our metabolisms obviously differ. So, that’s why it’s unclear if the benefits at this level would easily translate to humans.
Some of the other benefits include:
Reduced levels of inflammation
Increased production of neurotrophic factors that stimulate something called neurogenesis, which is a process that supports the overall growth and survival of neurons
Optimum hormonal profile
Increased autophagy, (removal of cellular waste)
Better weight loss - Primarily in obese individuals
This is likely to occur because only giving someone a narrow window in which they can eat ultimately facilitates caloric restriction by simply eating less food.
Fasting can have an appetite blunting effect (after the initial switch from normal eating patterns to intermittent fasting).
Potential problems or drawbacks
There’s no hard set rule of what intermittent fasting is. Like I said before, there are several options out there, so it makes creating scientific studies difficult because the fasting period can vary so much.
There are possible side effects that can occur such as headache, fatigue, heart burn etc and it can be potentially seriously dangerous especially if you have a pre-existing medical condition. No long term studies available that follow those who intermittently fast for years and can accurately predict specific outcome measures.
My overall thoughts
There appears to be new, upcoming, and promising medical research suggesting intermittent fasting can be quite beneficial. Try it for yourself and see how you feel! However, I’d be wary on trying this for extended periods of time due to unstudied long term outcomes that are either positive or negative. Try cycling intermittent fasting, in whichever manner you choose, in 1-2 month periods followed with a month long “wash out” phase.
Last thing: Before you start intermittent fasting, please consult your local health care provider to make sure intermittent fasting would be safe with YOU!
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