Intermittent fasting has become increasingly popular over the last few years, and it's far from being a fad or a Hollywood starvation scheme. It's been idolised, criticised and misinterpreted: fasting does NOT mean punishment or starvation. Used correctly, it's a powerful tool to improve your wellbeing and regulate your body's hunger signals. Used improperly, it can be a trigger for yo-yo dieting patterns and eating disorders.
We put together this short guide to help you if you are considering Intermittent Fasting, drawing on the latest research available, benefits, and sharing our own experiences and point of view from a holistic sports science & wellness approach.
Intermittent fasting simply means there are times in the day/week when you eat, and others where you don't. Eating usually happens within a set window of time of 10-12 hours. Our goal today is to approach the subject of intermittent fasting with a holistic wellness point of view, using our experience, observation, and the available information to share:
The background of fasting practices
The benefits
How it works
The types of fasting
The risks & safety guidelines
BACKGROUND Fasting is as old as time. Not only does it form part of cultural practices (think of Lent and Ramadan) - but we can go further back in time to unveil a timeline of food availability and man.
2020 AD - 97% of homes in developed countries have a refrigerator. Our refrigerator and pantry is stocked full of ready-made food. Cheap food is more expensive than whole foods. If these stores are empty, we can drive to the shops and restock. If we're really stuck, it's UberEats. Availability: 10. Effort: ZERO.
1959 AD - 13% of homes have a refrigerator, pantries are stocked weekly. Canned ready-meals emerge but most meals are created from scratch (if you're really posh, by the house cook). Availability: 8. Effort: TWO.
1500 AD - A cupboard or pantry will store the scarce amount of food you can afford. You'll be lucky if you see more than soup and bread. Eating meat is a yearly occasion. If you're lucky, you have a goat/cow to use for dairy, and a chicken or two. If you're really, really posh, you have an ice-box and a team of cooks. You can buy food by trading or coins at the market. More advanced food preservation is possible by way of pickling and salting. Availability: 5. Effort: SIX
10,000 YA - Agriculture kicks off; you work and eat off the land. Your community grows all of the available sources of food, which you can trade (or fight for). You start making more than you can eat, so man thinks of more clever ways to preserve food (such as smoking it). Availability: 5. Effort: SEVEN
400,000 YA - Hunting becomes a little easier. At least now you have pointy wooden sticks (spears) to fish and hunt. You eat what you can, when you can - but when you kill a woolly mammoth you realise you need to preserve it (such as drying it). Availability: 3. Effort: EIGHT
1.9 million YA - Hunter-gatherers need to live by the philosophy of "carpe diem" - seize the day, and more importantly: eat what you can seize. Children and women pick for berries and edible plants, while the men throw sticks and stones to catch fish and small animals (remember, spears have not yet been invented). Availability: 2. Effort: TEN
Why is this relevant to fasting? Food availability versus effort has a direct consequence to our health. To understand WHY intermittent fasting can be so beneficial to our bodies, we need a little perspective. In the last 50 years, food has become increasingly available and requires no effort to be obtained. Yet over 1.9 million years, our bodies have evolved and adapted to the scarcity of food and the effort (movement + energy) required to provide it. BUT WE'RE EATING LIKE IT'S CHRISTMAS. Every. Damn. Day.
Essentially, affluent modern man:
Eats too much and moves too little
Eats too many calories but too few nutrients
IS IN CONSTANT DIGESTION
IS ALWAYS HUNGRY
THE BENEFITS OF FASTING: Being in a state of constant digestion is not only unnatural for our body, but it's highly problematic. Do you ever have your laptop on constantly, with a million windows open, without allowing it to switch off or re-boot? (I'm guilty here!) Our digestive system is pretty similar. It takes an average of 36 hours for food to go through the "full circle of life" from the yummy chewing part until the, ahem, exit. That's a day and a half of mechanical and chemical grinding, separating, organising, and storing. Now imagine this entire process having to restart EVERY TIME YOU EAT SOMETHING. That is your digestive system operating at full speed, all the time. It's like opening a new window on your laptop without ever closing it, and keeping your insulin levels high (hello, insulin resistance!) which leads to chronic inflammation. Research concerning intermittent fasting (either as a health or spiritual practice) has shown mixed results concerning health and weight loss. There are many claims which are founded on mixed research (both on humans and animals) - but what ARE the things we can actually rely on? Fasting:
Provides a digestive rest - It ensures your digestive organs take a break, reducing the stress on your body. People with digestive discomforts find that a digestive rest can minimise irritation.
Regulates hunger - A gradual, consistent change in eating patterns regulates ghrelin and leptin, our hormones responsible for hunger and satiety (see below).
Reduces calorie intake - Even without this being a specific goal of fasting, minimising your eating window reduces the opportunity for excessive snacking and volume of ingested foods. You'll find you simply cannot eat as much!
Boosts your energy levels - At the start of the fasting practice and towards the last hours of your fast, it's normal to feel a little lethargic. However, as your body adapts you may notice peaks of mental and physical energy in the middle of your fasting phase - even during exercise.
Supports the immune system - By giving our digestive system regular breaks, our body is able to direct more energy toward servicing our various immune cells, ensuring they're always ready for a fight against pathogens that may find their way in.
HOW IT WORKS: Appetite control: Fasting can be a simple but highly effective strategy for weight loss and eating impulses. It invokes less confusion by giving more precise instructions; it does not restrict food groups or require calorie counting. Instead, it relies on regulating two hormones, which will determine our hunger levels, regardless of what our body really needs:
GHRELIN: Feed me! The hormone responsible for those hunger pangs (AKA being HANGRY) is usually released into your bloodstream when it expects a meal. When you teach your body to expect food fifteen times a day, guess what...your ghrelin monster manifests itself more often, and you end up feeling hungry all day. Ghrelin is released by your gut to say "HEY, FEED ME!" when it expects food, usually around 30 minutes before your usual eating times. What's interesting is that after this initial hunger pang (AKA a ghrelin tantrum), the ghrelin will dissipate for a few hours - even if you don't eat - and return at your next scheduled meal time. Training your stomach to be more patient gradually DELAYS the release of ghrelin for longer intervals, meaning you start feeling hungry less often.
LEPTIN: Your tank is full/empty. Leptin, produced by fat cells, is released based on the nutrient value of the food ingested. Leptin signals to the body that you are satiated, or have received enough nutrients for now. The "tank" does not consider the calories in a meal; rather, leptin responds to the nutritional value of that meal. 1 tub of Ben & Jerry's ice cream = high volume of calories, low volume of nutrients = low leptin; hunger levels stay high. 1 tub of vegetable/meat stew = lower volume of calories, high volume of nutrients = high leptin release; hunger levels drop. Remember: your "tank" gets filled with nutrients, not calories! If your tank is empty, you'll still be hungry! After a period of fasting, leptin levels have been shown to rise faster after mealtimes, indicating that