I had a supervisor during my clinical rotation who challenged my recommendations of eating 5 meals a day to a patient. This was and still is such a deeply held belief in medicine that I seriously thought he was either just challenging me for the fun of it and for lack of anything else to pick on or he really didn’t know what he was talking about! I thank him now as that seed he planted in my mind is now taking root as more and more evidence emerges supporting this notion of eating one meal a day -termed intermittent fasting- as opposed to the conventional recommendation of regular eating.
Intermittent Fasting, a way of eating intuitive to some and a way of life for others is now gaining credibility as studies on intermittent fasting shocked the world with the news that this drastic pattern of eating yielded a substantial increase in the lifespan of rodents along with outstanding improvements in major health markers including insulin sensitivity, body composition and neuro-regeneration capacity.
As this is a slightly vague term, followers of this regimen may choose to skip a certain meal in the day, fully fast every other day or every other week, or/and…a myriad variations in eating may be considered ‘intermittent fasting’.
But isn’t fasting bad for you? And which plan should you follow?
Let’s look at the science:
Note that there are cases that may prohibit long-term fasting, such as with young children, type I diabetics (on insulin medication), or in cases of clinical myopathy (muscle wasting).
So, how can fasting benefit you?
Scientists acknowledged three major mechanisms by which fasting benefits your body, as it extends lifespan and protects against disease:
- Reduced oxidative stress – Fasting decreases the accumulation of oxidative radicals in the cell, and thereby prevents oxidative damage to cellular proteins, lipids, and nucleic acids associated with aging and disease.
- Increased insulin sensitivity and mitochondrial energy efficiency – Fasting increases insulin sensitivity along with mitochondrial energy efficiency, and thereby retards aging and disease, which are typically associated with loss of insulin sensitivity and declined mitochondrial energy.
- Increased capacity to resist stress, disease and aging – Fasting induces a cellular stress response (similar to that induced by exercise) in which cells up-regulate the expression of genes that increase the capacity to cope with stress and resist disease and aging.
It is also noteworthy that almost all world religious , philosophies and doctrines (for example Shinto, Buddhism, Hinduism, Judaism, Christianity, Islam, Babi and the Baha’i Faith) bid their followers to observe fasting in some form (i.e. abstain from food and drink for a period of time) as a way of physical, mental and spiritual exercise, discipline, invigoration and purification -with some logical exemptions for the young, old, sick, nursing and pregnant women, etc.
Operating around your system’s innate circadian clock:
Your innate clock, called the Suprachiasmatic Nucleus (SCN) is located in your hypothalamus, where it regulates how your autonomic nervous system operates along with your hormones, your wake and sleep pattern, your feeding behaviour, and your capacity to digest food, assimilate nutrients, and eliminate toxins. There is a dual relationship between your feeding and innate clock. And as much as your innate clock affects your feeding, your feeding can affect your innate clock. Routinely eating at the wrong time will disrupt your innate clock and devastate vital body functions; and you’ll certainly feel the side effects as your whole metabolic system gets unsynchronized.
All your activities, including your feeding, are controlled by your autonomic nervous system which operates around the circadian clock. During the day, your sympathetic nervous system (SNS) puts your body in an energy spending active mode, whereas during the night your parasympathetic nervous system (PSNS) puts your body in an energy replenishing relaxed and sleepy mode.
These two parts of your autonomic nervous system complement each other like yin and yang. Your SNS, which is stimulated by fasting and exercise, keeps you alert and active with an increased capacity to resist stress and hunger throughout the day. And your PSNS, which is stimulated by your nightly feeding, makes you relaxed and sleepy, with a better capacity to digest and replenish nutrients throughout the night. This is how your autonomic nervous system operates under normal conditions.
If you eat at the wrong time such as when having a large meal during the day, you will mess with your autonomic nervous system; you’ll inhibit your SNS and instead turn on the PSNS which will make you sleepy and fatigued rather than alert and active during the working hours of the day. And instead of spending energy and burning fat, you’ll store energy and gain fat. This is indeed a lose-lose situation.
With the circadian rhythm in mind, through simple deductive reasoning then, it is clear that the best time to eat is at night!
What About Breakfast, You Say?
The meal commonly believed to be ‘the most important meal of the day’! But what does breakfast mean exactly? To most, it’s the first foods we stuff ourselves with. Be it a fast food purchased on our way to work or a nice hearty meal of toast, dairy, jams and cereals. But let’s approach ‘breakfast’ from a historical and scientific perspective.
Breakfast literally is understood to be a breaking of a fast. Now, a fast is generally understood to be a minimum of 12 hours of no food consumption while it typically takes your body between 6-8 hours to fully digest a hearty evening meal (depending on your meal density – content of protein and fat, etc). If, for example you start your evening meal at 7pm and finish eating at 8-9pm, your body will shift into a fasting state by the early morning hours (about 4-5am). Hence, your body will not be in a fasting state for most of the night and breaking your fast at about 7-9 am only gives your body about 3-5 hours of ‘fasting’.
Historically, some of the healthiest societies in the past did not eat breakfast; the word breakfast was not part of their vocabulary and the typical breakfast did not exist during Biblical times. In the original Hebrew text of the Bible, breakfast is called “pat shacharit” which meant a tiny piece of bread at dawn – nothing more. As well, the ancient Greeks and Romans were very particular about eating their main meal at night.
Scientifically, there is growing evidence that the typical breakfast can be harmful. A study by the Human Nutrition Research France1 indicated that the typical high energy breakfast caused major adverse effects including a strong inhibition of fat burning throughout the day, increase in serum triglycerides and a decrease in HDL (good cholesterol). The researchers concluded that high-energy breakfast does not appear to be favourable to health; they also indicated that the study’s results do not support the current advice to consume more energy at breakfast. Moreover, reports coming from epidemiological surveys have been indicating that the consumption of a high energy breakfast leads to a significant higher energy consumption for the whole day. Furthermore, a big breakfast has shown to yield only a limited satiety effect which lasts merely 2 hours after breakfast.
Therefore, if we are to break fast in the morning, it is wise to ensure that we are indeed breaking a fast and to do so with nothing more than a light snack and only if we are truly hungry!
So What Could One Eat While Fasting?
This is not meant to be a harsh starvation diet and although most foods negate the effects of fasting, there are foods that can be safely eaten without compromising your fast. These include fast assimilating nutrient-dense foods such as quality vegetable proteins, green vegetables and berries. It is also just as important to know how much to consume and how often.
Small servings (~100Kcal) of vegetable proteins (nuts, seeds & legumes), green vegetables and berries can be eaten every 3-6 hours depending on your level of physical activity -when hungry. According to one advocate of such a diet Ori Hofmekler (the author of The Warrior Diet), one to two servings of whey protein should also be supplemented in the diet during the fast. I’d highly recommend this to those who have a difficulty in incorporating a fast assimilating (non-meat) complete protein throughout the day.
Note, although this diet can be beneficial for the majority of us, there are those who may require alterations depending on their current state of health and their nutritional needs due to their occupation, hobby or stage of life (i.e. athletes with high nutritional needs, pregnancy/breastfeeding, etc.). As always, please consult your health care provider before embarking on this therapeutic health program if you’ve got any health concerns.