Are you one of those people who believe fasting is detrimental to your health? If so, then please read this article because I’m busting the common myths about fasting.
I grew up in a traditional Catholic household. This meant that whenever I heard the word, “fasting,” I thought it was only for religious purposes. It wasn’t until two years ago that I heard about fasting as an every day practice.
At first, I thought this was a nutty idea. I mean, who deprives themselves of food on purpose?! But the more I read about it, the more I was intrigued by it. So in July of 2015, I decided to try it myself.
To be honest with you, I received a lot of negative feedback about my intermittent fasting. Most people thought I was crazy. “Didn’t I believe that breakfast was the most important meal of the day?” I have to admit, I did fall for that logic for a long time. “Aren’t you going to lose muscle?” “Why would you want to starve yourself?” “You are crazy!”
What’s crazy to me is that fasting has been around since the beginning of time, yet these common myths still persist about fasting. Today, I want to bust through the common myths and share with you WHY these are just myths and that fasting can actually help achieve optimal health!
MYTH #1: Fasting makes you burn muscle
This is probably the #1 comment I get about fasting – that my body is going to eat my muscle for fuel.
This does not actually happen. Why? The human body has evolved to survive periods of fasting. Our body stores food energy as body fat and uses this energy when food is not available. Muscle, on the other hand, is preserved until body fat becomes so low that the body has no choice but to burn muscle. This will only happen when body fat is less than 4%.
If our bodies burned muscle rather than fat when food was scarce, we would have never survived long as a species. If we are eating normally, our energy comes from a mix of carbohydrates, fat, and protein. As you start fasting, the body starts to burn the sugar (from the carbohydrates) for the first 24 – 48 hours after you stop eating until it runs out of glycogen. When the sugar is gone, the body switches to burning fat.
In fact, fasting is one of the strongest stimuli for growth hormone secretion, and increased growth hormone helps maintain lean body mass. If you are worried about muscle loss, the most reliable way to build muscle is through exercise.
During fasting, hormonal changes kick in and give us more energy (increased adrenaline) and preserve our lean muscle mass and bones (increased growth hormone.) This is normal and natural and is nothing to fear.
Just check out my progress photos…I’m NOT losing any muscle. In fact, I’m building it!
MYTH #2: Fasting puts you in starvation mode
Maybe you’ve heard that skipping a meal or two will put you into starvation mode?
What exactly is starvation mode? It’s when our metabolism decreases severely enough for our bodies to shut down and stop burning energy. This can be tied to our basal metabolic rate (BMR.) Our BMR measures the amount of energy our body burns in order to perform its basic functions – lungs breathing, heart pumping, brain function, digestive system working, etc. Most of the calories we spend each day are not used for exercise but for these basic functions.
Our BMR can increase or decrease up to 40% in response to many variables (i.e. temperature.) Daily caloric reduction can also cause a dramatic reduction in BMR. For example, someone who normally eats 2500 calories per day and then reduces their calories to 1500 per day for a long period of time will result in a 25 – 30% reduction in BMR. The reverse is also true; when people overeat, this causes an increase in BMR.
Because of this effect of calorie reduction on BMR, many people assume that fasting will have the same affect. However, this does not happen. Our bodies do not shut down in response to short term fasting. In fact, metabolism revs up, not down, during fasting!
Our hormones allow our body to switch energy sources from food to body fat. By feeding on our own fat, we significantly increase the availability of “food,” and this is matched by an increase in energy expenditure.
One study showed that fasting every other day for 22 days did not lead to a decrease in metabolic rate, but the participants lost 4% of their fat mass, which is impressive for a period as short as 3 weeks (1).
MYTH #3: Fasting results in overeating
Many people warn against fasting because they say it will cause you to be extra hungry which leads to overeating and ultimately no weight loss.
This is partly true. After a fast, people automatically tend to eat a little bit more than if they hadn’t been fasting.In other words, they compensate for the calories “lost” during the fast by eating more during the next few meals.
However, this compensation isn’t complete. One study showed that people who fasted for a whole day only ended up eating about 500 extra calories the next day (2). They expended about 2400 calories during the fasting day, then “overate” by 500 calories the day after. The total reduction in calorie intake was then 1900 calories, which is a very large deficit for only 2 days.
I have actually found that fasting tends to decrease my appetite, especially as the fasting duration increases!
MYTH #4: Fasting deprives the body of nutrients
There are two types of nutrients: macronutrients and micronutrients.
Macronutrients are proteins, fats, and carbohydrates. Micronutrients are vitamins and minerals that are provided by out diet that are required for overall health.
With shorter fasting periods (less than 24-hours), there is plenty of opportunity before and after the fast to eat nutrient-dense foods to make up for missed meals. For longer fasts, it is a good idea to take a multivitamin to prevent any vitamin deficiencies.
Of the three major macronutrients, there are no essential carbohydrates the body needs to function. However, there are certain fats and proteins that we have to get in our diet. These are called essential fatty acids and essential amino acids.
During fasting, our body reduces the losses of these amino acids and fatty acids by decreasing bowel movements. To further preserve proteins, the body breaks old proteins down into their component amino acids and recycles these into new proteins.
Even though this process is happening, when we are fasting, we are not consuming more of these essential fatty acids and amino acids, so it can be helpful to follow a low carb diet, which increases the percentage of fats and proteins consumed so the body has more stored energy when food isn’t readily available.
MYTH #5: Fasting causes low blood sugar
When I was about to begin my intermittent fasting, I was so scared that I would become shaky and sweaty due to low blood sugar. I was actually travelling the first time I tried fasting, and was going to be on an airplane most of the time. However, I was pleasantly surprised. I felt no dizziness, no shakiness, and no sweatiness!
During fasting, our body begins by breaking down glycogen (glucose that is kept in short-term storage) in our liver to provide glucose. As we sleep and don’t eat every night, this process keeps our blood sugars normal. If we wake up and continue fasting, our glycogen stores become depleted. However, the liver can manufacture new glucose in a process called gluconeogenesis. This means that we do not need to eat glucose for our blood glucose levels to remain normal.
Between the glucose we have already stored away in the form of body fat and what the liver produces in gluconeogenesis, we have plenty of fuel when no food is available.
I hope that I’ve debunked the myths about fasting for you. After reading that, are you ready to give fasting a try? Let me know in the comments below!
If you’re interested in combining fasting with a low carb, high fat, moderate protein way of eating but aren’t sure where to start, consider joining one of my upcoming Drop a Dress Size challenges!