Intermittent fasting is getting a lot of attention in the nutrition community today. Perhaps it is because the paleo diet is getting a little old news these days. No one likes a trend more than the health-conscious community, and intermittent fasting is the darling at the moment. And for good reason.
Intermittent fasting is the method of abstaining from or reducing the intake of food for a certain amount of time. The objective of this restriction is to encourage the body to burn body fat. We are also seeing that there is plenty of evidence that there is a multitude of health benefits from intermittent fasting.
The human body is suited for fasting as our ancestors never had access to food 24/7. Instead, they went through natural phases of feast and famine. Thankfully we now have access to food when we need, so we can hack the fasting phase to a specific time to prevent the detrimental effects of long-term fasting that our ancestors faced.
How does Intermittent Fasting work?
When you eat, insulin is released into the bloodstream and moves glucose (carbohydrates) into your muscles and other tissues where it is used for energy production. When there is excess glucose your body will store this in adipose tissue, in other words, it is converted to fat.
When you fast, the hormones glucagon and cortisol stimulate the release of the stored fatty acids from adipose tissue into the bloodstream. These fatty acids are used by the muscles and other tissues to produce energy. Basically, you burn body fat.
When we constantly graze throughout the day, your body has a constant supply of easily accessible energy and will not need to dip into fat stores for energy.
Benefits of intermittent fasting
When we have a break from eating, or drastically reduce what we eat, our body benefits in a number of ways –
- It gives your digestive system a break and allows restoration to occur (just like it does when we sleep). When in a fasted state your cells initiate a cellular repair process called autophagy. We are beginning to understand that autophagy is the cornerstone of anti-ageing mechanisms.
- Human growth hormone is increased (nearly to a five-fold level), which promotes fat loss whilst maintaining muscle mass.
- It allows our body to tap into fat stores for energy, rather than from the food that has just been consumed.
- There is a change in hormone levels that allow the body to access fat stores more readily.
- Improves insulin sensitivity, allowing the food you consume to be used more efficiently. When insulin levels drop, your metabolism can access fat stores more readily.
- It allows us to truly feel our hunger. There is nothing wrong with being a little bit hungry
The key to successful intermittent fasting and sustainable weight loss is becoming metabolically flexible. What this means is that your body can easily switch between burning fat for fuel in a fasted state and carbohydrates for fuel in a fed state. Another word for this is ‘fat adapted’. In this state of metabolic flexibility, your body can effortless (without you feeling hungry and fatigued) burn fatty acids for energy as soon as glucose (carbohydrate) stores have been used.
People who are ‘carb adapted’ struggle to lose weight as their body does not readily use fat for fuel when in a fasted state. Whilst they still release the fatty acid when they are in a fasted state, their body cannot easily convert this into fuel. The build-up of these fatty acids in the bloodstream is thought to be a cause of insulin resistance and will result in weight gain.
What intermittent fasting or more specifically time-restricted eating can do is train your metabolism to become flexible. It allows your body to reset its hormone production in response to food, and eventually improve your ability to lose weight. This is particularly true if you improve your food choice during your feeding period. This includes increasing the amount of healthy fast that you eat. A low-fat diet will reduce your bodies ability to release fatty acids for energy production. When you incorporate more fat into your diet, your ability to release stored fatty acids for energy production int he muscles will increase. This all helps to improve your metabolic flexibility.
How to implement Intermittent Fasting
There are a number of ways to implement Intermittent Fasting into your lifestyle, such as complete fasting, reduced feeding windows or the 5:2 diet. Studies have shown that men benefit from all the different types of Intermittent Fasting protocols, whilst women do better on the 5:2 style of eating.
Time Restricted Eating (TRE)
In this method, you are condensing your ‘eating window’ to 6-8 hours within a 24-hour period.
For example, you eat between 11 am and 7 pm. With this method, you naturally eat around 2 meals and one snack in this time frame. Whilst you give your body a rest from eating for around 16 hours, you ultimately end up consuming fewer calories. It is this calorie restriction that will help you to lose body fat, whilst still getting the health benefits of hormone balancing, meta and cellular repair as seen extended fasting.
A reduced feeding window is a method that is very easy to stick to. I advise people to reduce their feeding window 3-4 times per week, however, many people choose to do this daily. The flexibility of this plan still allows people to eat out, and not have the need to restrict food groups. However, it is essential that healthy diet choices are made during the feeding time, otherwise, the benefits of fasting will be lost.
Longer Intermittent Fasting Periods
In this method, you can fast for up to 24 hours once or twice a week (not on consecutive days). The best way to do this is to stop eating at 6 pm one day, and then not eat until 6 pm the next day. This way you are not having a whole day with no food. Ensure that the meal that you do have at the beginning and at the end contains all macro-nutrients – fat, protein and carbohydrate. Eat a healthy amount at these meals, but don’t gorge yourself.
This method is harder to follow and it is not suitable for everyone. Women with hormonal imbalances or those with blood sugar issues should avoid this type of fasting unless it is done under the supervision of a health professional.
The 5:2 method is a successful weight management strategy. However, the 5:2 is not a true form of intermittent fasting as you are not actually abstaining from food. Instead, you are having two days of heavily restricted calories. This method works by reducing your calories to 500 calories for women and 600 calories for men on any two days of the week. These days can be consecutive or split apart. On the remaining 5 days, you eat your normal healthy diet. The key to this method is not to binge out on the 5 days, as this will undo all the results achieved on the restricted days. On the low-calorie days, it is recommended that you reduce your ‘eating window’ to 8-10 hours so that you can get some fasting done.
The 5:2 is popular and successful as it is very easy to follow, not just during the weight loss phase, but long term. I can not stress enough, that if the method you use to lose weight is not sustainable, then the weight will come back on once you stop the diet plan. To add to this, most people wreck their metabolism when dieting, and thus end up gaining more weight back, than just the kilo’s that were lost.
Exercise and Intermittent Fasting
Many people ask if you should exercise in a fasted state. Studies show that you do burn more fat when exercising in a fasted state, however, there is a catch. Your body will also release more cortisol when you exercise in a fasted state. Whilst we need cortisol to manage our stress response, too much can be detrimental to many areas of your health, including weight loss, sleep and anxiety.
So anyone who is under a lot of stress or has issues with their adrenal glands should avoid exercising in a fasted state. For those who have their stress under control, then exercising in a fasted state may accelerate your weight loss.
Will I lose muscle mass when fasting? No. Muscle loss will begin to occur when fasting extends for several days. The methods mentioned above are short enough to prevent your body from tapping into muscle stores for energy.
Can I drink when I am fasting? Yes. Tea, coffee and water are all suitable when fasting. A fast is broken when an insulin response is initiated from food. As long as no milk or sugar is added to these drinks, then an insulin response won’t happen. There is a lot of anecdotal evidence that coffee will help to reduce your appetite and will enhance brain function, all of which will help you get through your fast. I recommend having Bulletproof coffee during your fast to enhance fat burning, alertness, energy and to reduce appetite.
Can I fast if I am pregnant or breastfeed? The simple answer is NO. The nutritional demands of pregnancy and breastfeeding are not compatible with any form of fasting. Nor is there any evidence to prove its benefits and lack of risks.
What if I get hungry? No drama, simply break you’re fast and have something to eat. It is important to listen to your body, and if you are feeling light-headed, nauseous or unwell you need to stop your fast. You may need to work your way up to extended fasts or time-restricted feeding windows. Start with a shorter fast and slowly increase it as your body adapts.
Ready to give intermittent fasting a try?
Choose one of the methods above and give it a try. If you don’t adapt to fasting easily it might be worth having a chat to see where you are going wrong, or if there is an underlying health issue that may be causing this. You can book in a FREE 15-minute discovery sessions to chat about how naturopathic medicine can support you and your health goals.