Weight-loss is the main reason many of us gravitate towards intermittent fasting (IF). Beyond just that, IF benefits extend to improved focus and energy, enhanced organ detox, healing illness and even reverse the signs of aging. 
Sounds too good to be true, right?
We thought so, until we experienced it for ourselves. As parents, in our 40s we’ve tested and tried many diets and lifestyle changes, and in the end have stuck to IF since 2013.
Fasting is an ancient tradition that is on trend not only in North America but worldwide. The medical literature on fasting is growing quickly with overwhelming majority showcasing numerous restorative health benefits.
With todays beyond 9-to-5 lifestyle, intermittent fasting (IF) has a strong appeal of convenience and application to any diet be it keto, palo, vegan and beyond. However, there are questions and myths regarding fasting such as starvation mode, low energy, muscle loss, and skipping the most important meal of the day—breakfast.
In this article, we’ll explore these topics (from a personal and scientific view), how IF affects the body and the benefits that come with it, especially weight loss.
Intermittent Fasting 101
Intermittent fasting is not a modern fad or latest diet but, simply a way that you cycle between eating (feeding) and not-eating (fasting). The fasting periods are flexible and up to each individual.
Some people fast daily restricting a feeding window anywhere from 2 to 12 hours. Others prefer to do a full 24 hour fast every other day. There are weekend (48 hour) fasts where you may consume minimal (500) or no calories.
Mistakenly IF gets confused with starvation, but there is a difference.
Starvation is the uncontrollable absence of food. Meaning, there’s no food in sight and unknown when it will become available. Fasting is simply a withholding of food on purpose with a set end time. 
Also, there are no hard and fast rules with fasting regarding specific times. We simply enter a fasting state each time we’re not eating. For instance, overnight period between dinner and breakfast the next day may be 10-12 hours, and in a sense we all IF daily.
This restricted time eating compliments our genetically evolved energy production and storage mechanisms, thus carries numerous health benefits. The body is well equipped to perform in a fasted state for a long time. Modern record is 382 days where a man lost 125 kg (276 lbs) with no negative side effects. [2-3]
Skip Breakfast For Sustainable Weight-loss
Have you ever felt that you’re just not that hungry when you wake up?
If so, you’re not alone.
Many of us don’t feel like eating in the morning but, believe that we should. It has been ingrained in us that breakfast is “the most important meal of the day” and skipping it ignites hunger, messes up hormones, leading to constant overeating and weight gain.
Breakfast studies often scare us with associating factors of how not eating it may jeopardize our health. [4-6] But, a closer look at the research data shows inconsistencies that don’t add up.
It’s important to remember the difference between association and causality. Majority of pro-breakfast research uses vague language describing associating factors, not causing factors.  These papers either review science experiments or collect questionnaires from people of various walks of life, medical history, stress levels and many other factors which make us different and unique.
Compiled information from such case-studies is often dispersed and shows no particular pattern. Researchers that analyze such data draw loose associations between not eating breakfast and weight gain or development of some kind of disease. [5-6]
Afterwards, these interpretations are marketed as “scientific proof” which is far from facts that fail to show any causation or protective effects to eating breakfast. Furthermore, many reports are skewed, bias and often sponsored by the big food companies who have a direct profit gain for favourable results.
The truth is that there’s nothing special about breakfast. Breakfast literally means, first meal that breaks the fast. Fasting research examines timed eating patters including when to have the first meal.
Current analysis shows that skipping breakfast will not make you gain weight [1,8] or diminish metabolism. [1,9] The message here is “listen to your body”. If you don’t feel like eating first thing in the morning, then keep fasting and extend your first meal for few hours around lunch time.
And, if you are hungry?
Then, go ahead and have nutrient-rich foods to break your fast, but finish the feeding window earlier and forgo dinner. This is the beauty of IF; as it is flexible and adaptable to any schedule or metabolic clock.
Skipping dinner holds its own benefits including decreased appetite, greater fat burn and weight loss that can be maintained long term. [10-12] Few larger meals consisting of quality fats, carbs and protein eaten during the day increase metabolic activity better than multiple smaller meals and snacks. 
This misconception of frequent eating being healthy works against us, as extra energy isn’t burned but rather stored on the waistline.
Your Body Is Adapted To Fasting
Fasting is engraved in us. Throughout 300,000 plus years of evolution as a species, we developed brain size and cognitive capacity along with numerous systems necessary for survival. This includes eating various types of foods and ability to store energy for times of famine. 
Abstaining from food (or fast) carried over to the civilized world and became part of the oldest traditions and religious practices. Most religions including Buddhism, Christianity, Judaism, Islam and Hinduism perform various fasts. [14,16]
The health benefits associated with fasting became a popular healing practice in the ancient times such as Ayurvedic medicine and ancient Greece.
Hippocrates of Kos (460 – 370 BC) considered the father of modern medicine often prescribed fasting and cider vinegar to his patients.  Other famous Greeks including Pythagoras, Plato and Aristotle indulged in fasting protocols.
More recent figures like the Swiss physician and founder of toxicology Phillip Paracelsus preached fasting to be “the greatest remedy—the physician within”.
And, Benjamin Franklin himself was an IF believer and practitioner.
3 Different Types of Eating Windows
There are various types of IF protocols, but they all tend to fall under three main methods including: [16,18]
Alternate-day fasting: 24-hour alternating fast days between feeding. A Complete alternate-day fasting is when you eat no calories during fast days. A Modified alternate-day fasting entails consuming minimal calories (500 or so), less than 25% of daily energy needs during the fast.
Periodic fasting: Fasts that last longer than 24 hours at one time. The popular form of such timeline is the 5:2 diet where you eat regular schedule for five days and go into a two day fast by end of the week. Again, some people choose to consume no calories during fasting periods, while others take-in 500-600 calories (or up to 25% or daily energy intake).
Time-restricted feeding: These are daily fasts lasting less than 24 hours. Pushing or skipping a meal and extending the fast up to 14, 16 and even 20 hours each day is cycled with smaller feeding window. Such schedules are often easier to get used to and can be adjusted with internal circadian clock.
The Science Behind IF and Weight Loss
As our ancestors cycled between feast and famine, our body evolved in keeping a balance within internal systems. IF is a time-restrictive schedule between when you eat and voluntarily not-eat.  The body always maintains uninterrupted stream of energy by efficiently moving back and forth between feeding and fasting zones.
When we eat, the body breaks down ingested food into basic components such as energy, building materials and other nutrients. The excess calories are stored in forms of body fat (triglycerides) and sugar (glycogen). During fasting, the process is reversed as the body taps into its energy stores to maintain all metabolic needs. [1,18]
During feeding, the macro and micro nutrients from ingested foods are then absorbed thorough the digestive tract into the blood stream. Carbohydrates are separated/converted into glucose and then stored as glycogen (strings of glucose molecules) inside muscle (~2% of total weight), heart (~2%) and liver (~6%) accordingly. Smaller amounts of glycogen are also housed inside the brain (non-neuronal glial cells), kidneys, red and white blood cells, and even some fat cells. 
Glycogen requires water for storage. One part of glycogen needs three parts of water, making it large and heavy.  Once glycogen stores are full, the body keeps on storing energy, but in form of fat. This includes digested fatty acids and excess glucose that is converted to fat inside liver through de-novo lipogenesis. 
Fat is stable, low maintenance and stores easily throughout the body. While glycogen stores are limited, fat can be stored indefinitely within numerous cells and tissues. 
The feeding and fasting processes involve numerous hormones which partake in metabolic balance. Eating food releases insulin hormone into the blood stream. Insulin is the body’s switch that triggers energy storage phase by shuttling excess glucose out of the blood and into cells to be packed away as glycogen. The body can access glycogen much faster than fat and it can be used with or without oxygen.
Fasting lowers insulin levels and reverses the body’s energy shift from storing to using its storages.
Fat burning begins with glycogen breakdown into glucose (process called glycogenolysis) which then uploaded in to the bloodstream and delivered to cells. After about 12-24 hours of fasting the body begins to transition from glycogen to fat.
The switch is gradual as fat burning overlaps glycogen usage around 12-36 hours of the fast.  In doing so, the body activates numerous biochemical mechanisms which are dormant during high insulin state of frequent meals and snacks. [21,22]