There are many myths about fasting. Here are some popular myths:
Myth #1 – “Breakfast is the most important meal of the day!”
We have all been told to eat breakfast. Unfortunately this is terrible advice.
When you first wake up in the morning, your insulin level is quite low and most people are just starting to enter the fasted state, 12 hours after eating the last meal of the previous day.
The worst thing you could do is to eat food, spiking insulin and glucose and immediately shutting off fat-burning. A much better choice would be to push the first meal of your day out at least a few hours, during which you can fully enter the fasted state and burn stored body fat.
The VERY WORST would be to eat a high carbohydrate breakfast, spiking insulin and glucose as high as possible; in addition to shutting off fat-burning for likely 12 hours, this will drive as many calories as possible into fat stores as well as providing further reinforcement of the burning of glucose rather than fat.
Also, high spikes of insulin and glucose always lead to large drops in glucose a few hours later, which triggers HUNGER (if you want to have hypoglycemia or low blood sugar and ravenous hunger, just eat a breakfast of pure carbohydrates and then wait 2-3 hours to see how you feel). Interestingly, many properly fat-adapted people aren’t very hungry in the morning and have no problem skipping breakfast.
This is appropriate, as throughout our evolution humans have always been hunter-gatherers and rather than eating a large breakfast first thing in the morning we would hunt and gather throughout the day, having a larger meal later in the day. I highly recommend mimicking this pattern by skipping breakfast and eating most of your calories later in the day (referred to as a ‘reverse taper’ of calories, with none in the morning and most in the evening).
Myth #2 – “Eat small frequent meals.”
There has been plenty of worthless advice here. We have been told to eat frequently to “keep your metabolism going” and “don’t let your body enter starvation mode”. This is all the exact opposite of the truth: in order to burn fat, you want to spend as much time in the fasted state as possible and get very very efficient at living on stored body fat rather than caloric intake from constantly eating.
Similarly we have been told to eat protein frequently throughout the day in order to build muscle, and this is also not evidencebased. Yes you do want to eat an adequate amount of protein to build muscle, but eating it once a day is plenty.
Myth #3 – “Fasting leads to burning muscle instead of fat.”
Many people are concerned that if they start fasting they will either stop making muscle or maybe even burn muscle. This is not true. If this were true, humans would not be here today. In fact, growth hormone is increased during fasted states (both during sleep and after a period of fasting). Growth hormone might as well be called “fasting hormone”, as it rises by as much as 2,000% after 24 hours of fasting.
humanfood1Growth hormone is highly anabolic (builds muscle), and is used in combination with testosterone by bodybuilders who want to simultaneously build as much muscle and burn as much fat as possible. Growth hormone elevates in fasting to help preserve muscle in times of fasting, and this makes sense. In our hunter-gatherer ancestors, if fasting and going without food made you weaker and slower you would never catch or find any food and you would die and humans would become extinct.
In fact the opposite is true; while fasting, muscle is preserved or can even grow if you are doing resistance training (highly recommended). Also, people experience a increased level of focus and alertness during fasting thanks to the release of epinephrine and norepinephrine (earlier in our evolution this increased energy and alertness helped us catch prey when necessary).
Myth #4 – “Your metabolism slows down when you fast.”
This is completely false. A number of studies have proven that in fasting up to 72 hours, metabolism does not slow down at all and in fact might speed up slightly thanks to the release of catecholamines (epinephrine or adrenaline, norepinephrine, and dopamine) and activation of the sympathetic nervous system (sympathetic nervous system is often considered the “fight or flight” system, while the opposite is the parasympathetic nervous system or the “rest and digest” system).
It makes sense that this fight or flight sympathetic nervous system would be activated during the daytime, when hunter-gatherer humans are most active and in the fasted state (looking for food), followed by parasympathetic “rest and digest” mode in the evening after eating a large meal.
Myth #5 – “If I don’t eat I will get low blood sugar [hypoglycemia].”
Studies have shown that healthy persons who have no underlying medical conditions, who are not taking any diabetes medications, can fast for extremely long periods of time without suffering from any hypoglycemia. In fact, almost all sensations of hypoglycemia or low blood sugar (in non-diabetics) results from eating a very high glycemic index carbohydrate food a few hours prior (blood sugar spikes, then insulin spikes, then blood sugar drops rapidly).
However if you are a diabetic, especially if you are on any diabetes medications, you definitely need to check with your doctor before starting a fasting protocol. Some diabetes medications can lead to severe hypoglycemia when fasting (mostly insulin and sulfonylurea drugs like glipizide, glimepiride, and glyburide).
[Be sure to check with your doctor prior to starting a fasting protocol or any dietary changes or notable changes in your level of physical activity …. Insert Disclaimer and link to Legal section here]