Intermittent fasting is a hot topic at the moment and for a good reason. It's something I recommend to certain clients in my practice and it can have extremely favourable health results especially with weight loss and when done correctly. Here is what you need to know about it.
Like a car, our body requires fuel to carry out its important functions; from walking to a heart beat. The primary sources of fuel is sugar in the blood and glycogen; sugar stored in the muscles and liver for later use. In the absence of these two sources, our body breaks down fat stores for fuel.
When we are constantly eating, we are also constantly replenishing these glucose and glycogen fuel sources which means our fat cells stay fully loaded. As modern day life favours eating more food and moving less, these fat stores are bulking instead of breaking down, hence why obesity rates are rising.
How long does it take until your body starts breaking down fat?
It takes on average 6-8 hours after you eat for your body to burn though the glucose and glycogen stored energy in the muscles. After that point your body will start burning fat as fuel.
How does intermittent fasting work?
There are a few different ways you can structure your intermittent fast. A well-known one being the 5:2 structure whereby you eat normally for 5 days and fast for 2 days by eating under 500 calories.
An alternative and my preferred structure is the 16/8 hour one where you simply eat all your food in an 8 hour window and fast for 16 hours. This could mean you:
- East breakfast later in the day e.g. Eat from 11am - 7pm
- Skip breakfast completely and go straight to lunch e.g. Eat from 12pm - 8pm
- Eat breakfast early and have your last meal early afternoon e.g. Eat from 8am - 4pm
The 16/8 hour structure is easier than the 5:2 structure because you are sleeping for most of the fast, it’s more flexible and you aren't required to eat less calories therefore aren't starving all day. You eat the same amount of food, you're just eating in a smaller time-frame.
Will you get faster results by eating less food and eating in a smaller time-frame?
Initially you might lose weight but eventually you will start to put more weight on and it will be harder to lose. If you don't eat enough food in the 8 hour window, your body will think it's going to starve and will hold tightly onto its fat stores making it harder to shift the weight and start breaking down muscle instead. Your body will also respond by reducing its metabolic rate which means you become less efficient at burning calories and will cause you to gain more weight in the long term, especially when you revert back to your normal eating habits. You are not supposed to starve yourself.
Can you drink fluids during your fast?
Yes you can drink water, black coffee, and tea during your fasting period. I recommend adding psyllium husk to your water which is a great source of fibre and also an appetite suppressant as it swells in your stomach.
Won’t this cause muscle mass to break down, especially if I don’t fuel pre or post training?
Human growth hormone is a hormone that promotes growth, healing and repair of our cells. When insulin rises, this hormone is suppressed. In the fasted state, human growth hormone levels are at their peak which not only supports muscle growth but allows the body to clean up, repair and replenish damaged cells having healing and anti-ageing effects. This is why 8 hours of sleep per night is so important. As long as you are eating a sufficient amount of calories for your body type during the 8 hour window, you won't lose your muscle mass. Furthermore, exercising in a fasted state, will force your body to burn fat as fuel.
What other health benefits are associated with intermittent fasting?
- Improves insulin sensitivity so you can use carbs more efficiently as fuel. Effective for people with Type 2 Diabetes and insulin resistance.
- Reduces sugar cravings
- Reduces inflammation
- Reduces triglycerides
- Increases brain function through the production of ketones – a type of fuel the brain can efficiently use as fuel
- Lowers blood pressure
Is this way of eating for everyone?
No, this way of eating isn’t for everyone especially if you are pregnant, breastfeeding, hypoglycaemic or have a low body fat %. In these cases, fasting can stress your body and drive less favourable health effects. The key is to listen to your body and do what feels right for you.
Bear in mind, initially you might find it difficult as you are trying to train your body to become a fat burning machine. Give yourself two weeks and ease into it by fasting for 13 hours and work yourself slowly up to 16 hours.
Does it matter what you eat during your 8 hour eating window?
Of course. When it comes to good nutrition, quality is more important than quantity!
How many days a week should you fast?
I recommend starting off with 2-3 days and see how your body responds to it. If it works well, increase your number of fast days. It's also a great tool to use when in need of a reset, especially when overindulging throughout this festive season.
If you are interested in learning more or having a tailored weight loss/fasting program written for you, Get In Touch!
Like using apps? Download the Zero Fasting Tracker app from the Apple store to track your fast.