Beginner’s Guide to Fasting

What is fasting?

Fasting refers to the practice of going without food for a period of time. How long that period of time is depends on the goal of the fast; different periods of time kick off certain changes and healing processes in the body. People fast for all sorts of reasons including weight loss, weight maintenance, religious beliefs, detoxing, discipline training, pain control, disease prevention and inflammation reduction.

Some people fast for a chosen number of hours every day or most days (known as intermittent fasting or time-restricted eating), while others fast a couple of days a week (known as periodic fasting e.g the 5:2 Diet). Lots of people enjoy regular 24-hour fasts, while others prefer extended water fasts of 3, 5, 7, 10, 14, 21, 28, 30 and even 40+ days once or twice a year to reset their immune system and boost overall health, mood and weight.

If you’re planning to incorporate fasting into your life it’s a good idea to familiarise yourself with the different of types of fasts and to think about what might suit you best. Every body responds differently to fasting and, like all diets, what works for one person might not work for the next.

In my experience, the best way to approach fasting is to build up gradually, get used to how it feels to go without food and take on longer fasts once you know what to expect. Fasting, particularly water fasting (going without food) and dry fasting (going without food and fluids) can be particularly powerful – it’s a lot easier when you’re familiar with how your body’s going to respond physically and emotionally.

What happens to your body when you fast?

According to Dr Mindy Peltz, a fasting expert, “When you don’t consume food, the body looks for other ways to generate energy, such as drawing on glucose. Once glucose is significantly used up, the body begins to burn fatty acids from stored fat for energy. The body begins producing ketones. Ketones are a sign that your liver has moved from burning sugar to burning fat for energy. Once you reach ketosis, many of the benefits of fasting start to kick in. Benefits vary depending on how many hours you have been fasting.“

What are the benefits of fasting?

Fasting brings significant health benefits because it heals on a cellular level. Among many other things, fasting

• increases growth hormone
• stimulates autophagy
• slows the ageing process
• generates stem cell production
• helps stabilise blood sugar
• resets the immune system
• aids weight loss
• detoxes the organs
• lowers blood pressure
• improves mood
• helps reduce anxiety
• improves metabolism
• improves cognitive function
• improves autoimmune conditions
• normalises insulin and leptin sensitivity
• reduces hunger and cravings

There are several types of fasts. These include:

Intermittent Fasting

Intermittent fasting is where you abstain from food for between 13 and 15 hours in a 24-hour period and consume your food during a period of between 9 and 11 hours (known as an eating window). That doesn’t mean you continue eating for the entire 9 or 11 hours (like I used to!), it just means you consume all of your meals within that time. For example, you could fast from 8pm the night before until 11am (15 hours), have breakfast at 11am then have nothing until your next meal at around 8pm. Or you could have breakfast at 11am, lunch at 6pm and dinner at 8pm.

It really doesn’t matter when you eat but rather that you’re keeping the eating process to within 9 to 11 hours.

At around 13 hours of fasting, growth hormone production kicks in. Growth hormone is a peptide hormone produced by the pituitary gland that stimulates growth, cell reproduction and cell regeneration. It maintains body structure, helps us burn fat and helps keeps the metabolism in balance. It declines after the age of 30, which speeds up the ageing process but fasting boosts its production significantly.

Time-restricted eating

Time-restricted eating is the same as intermittent fasting but you decrease the number of hours between which you eat (the eating window). The most popular way is to do what’s known as a 16:8 fast, where you fast for 16 hours and eat within an 8-hour eating window.

A stricter approach is the 20:4 fast (my body’s preferred length of fast) where you have a 4-hour eating window and fast for the rest of the day.

At around 17 hours of fasting the body starts a process of repairing cells, killing off old or corrupted cells and clearing out toxins, known as autophagy. Healing is beginning to happen inside the body.

Fasting Mimicking Diet

The fasting mimicking diet consists of high fat, low carb, low protein, limited calories and specific macros in order to mimic fasting. It’s a good way to get the benefits of autophagy whilst still eating some food, because limited calories and low protein forces the body to release stem cells.

If you’re new to fasting or are unsure about going without food, this is a good option for you. It’s also a useful way to train your body to become used to longer fasts. Animal fats are satiating and nutritious, so help keep cravings at bay and help you to fast for longer.

24-hour FASTING / omad

24-hour fasting is when you go 24 hours until your next meal. For example you might eat dinner at 6pm then not eat again until dinner at 6pm the next evening. Also known as one-meal-a-day or dinner-to-dinner fasting, it’s a very effective weight loss and weight maintenance tool.

Done long term, however, according to Dr Mindy Peltz, eating once a day could have a negative effect on female hormones that they may not initially be aware of, as varying hormone levels during our cycle suit different types of fasts. Men seem to be okay long term eating one meal a day.

17-24 hour fasting stimulates cellular repair, detox, cancer prevention, gut repair, anxiety and depression reduction, and improvements to the brain and memory.

At 24 hours the healing process really starts kicking off. Growth hormone and BDNF production are stimulated. GABA (a neurotransmitter) increases and has a calming effect on the brain. Blood sugar levels are reducing significantly and intestinal stem cell production is initiated, which begins to repair the gut.

ALTERNATE DAY FASTING

Alternate day fasting is where you eat one day then fast the next day, or eat one day then greatly reduce your calorie intake the next day. You get the above benefits and it’s an effective tool for weight loss that’s slightly easier than 36-48 hour fasting.

36-48 HOUR FAST

The 36-48 hour fast is where you go for between 36 and 48 hours with no food. It’s a particularly effective weight loss tool and mood booster. People who are weight loss resistant or who have stalled in their weight loss find this a really effective type of fasting, even if done just once a week.

After 36 hours the body digs deeper to go in search of insulin (a fat-storing hormone) and glucose that the body has stored in the fat cells.

At around 48 hours, autoimmune conditions begin to see improvement and dopamine receptor sites are reset, which improves mood. The Krebs cycle within the cells is stimulated, which boosts energy and has an anti-aging, anti-oxidant effect. Metabolic switching is stimulated, as glycogen stores are now depleted and ketone production has begun.

Growth hormone is around five times higher at the 48-52 hour mark.

72-HOUR FAST / 3-Day Fast

It’s well-known that multiple-day fasting can reset the immune system and significantly improve chronic conditions. The longer you fast, the more the body will reach into your fat stores for fuel and the more ketones your body will produce.

A 3-day fast is like rocket fuel for the immune system because, along with all of the above benefits, at around 72 hours this fast will begin to regenerate immune system stem cells. Musculoskeletal injuries will begin to heal. BDNF neurogenesis starts to happen, which is like brain food.

5-day Fast

It’s amazing how powerful a 5-days fast is, even compared to a 3-day fast. This is like a miracle for the immune system, cognitive function, the mood, the organs – everything improves on a 5-day fast! It can be a challenge but after 3 days hunger reduces significantly so if you can get to 3 days you should be able to get to 5.

DRY FASTING

Unlike the other fasts, a dry fast means you won’t take in any fluids or food whilst on the fast. Some people insist that one day of dry fasting is equivalent to three days of water fasting, though there are no official studies to conclude this. Research does show, however, that it decreases inflammation and increases BDNF.

There are hard dry fasts (where you don’t even clean your teeth or have a shower to prevent any fluid from entering the body) and soft dry fasts where you do your normal routine but just don’t eat or drink anything. I’ve known people who claim to have done 3-, 5- and even 7- day dry fasts and report profound, life-changing experiences – personally I’d be cautious going for more than 24 hours. I tend to do 12-hour dry fasts naturally every day.