Intermittent fasting has been a buzz word for a while now. Popularised by celebrities like Jennifer Lopez and Kourtney Kardashian who practice intermittent fasting to burn fat, keep their skin glowing and minds sharp. It would be wrong to think of intermittent fasting as a diet. It's not, it's a pattern of eating. It's doesn't dictate what you eat but more when you eat it. Generally, intermittent fasting refers to a pattern of eating that involves either a daily 16 hour fast (16/8) or a 24 hour fast, twice a week (5:2). It's presented as a way to minimise calorie intake without crash dieting, making it an effective weight loss tool. Intermittent fasting followers also cite that the method is a great way to keep muscle mass while getting lean. More than a fad diet, intermittent fasting has scientific backing and could be a solution to an array of health issues.
What is Fasting?
Fasting has been part of the human condition for all of history. Historically, humans have gone without food when necessary and also by choice through religious ritual and tradition. Due to this, human bodies have evolved to function without food for extended periods of time.
Typically, the human body remains in a fed state as it's absorbing and digesting the foods we consume. In the fed state it's nearly impossible for the body to burn fat as the insulin levels remain high. In this fed state the body draws on stored glucose stored in the liver and muscles for energy.
Fasting is considered as such when the body is deprived of food for 16 hours. After this period the body goes into a fasting state of ketosis. This is where the liver breaks down fat and produces ketones which are used by the body for energy. Studies have shown the presence of ketones in the body can reduce appetite and decrease inflammation levels.
Fasting & Weight-Loss
The ethos surrounding intermittent fasting is mostly related to it as an effective way to lose weight. The science behind this is that when your body reaches the fasting state known as ketosis the body is able to burn fat that has previously been inaccessible. Entering this fasting state regularly means that you are continually burning fat, something unachievable on a regular eating schedule.
Intermittent fasting is said to actually change the hormone levels in the body further facilitating weight loss. Fasting lowers insulin levels and increases growth hormones, it also enables the release of a fat burning hormone called noradrenaline. Due to this, short-term fasting is understood to increase your metabolic rate.
There are no rigid rules when it comes to intermittent fasting. In fact, it comes in multiple forms each with their own methodology. Unlike a diet, people that intermittent fast can eat whatever they like between fasts with as much (or little) exercise as they feel is necessary.
Daily Intermittent Fasting:
This method is definitely the most practised approach to fasting. It follows the Leangains model which follows a 16:8 style, that is a 16 hour fast followed by an 8 hour eating period every day.
This 8 hour feeding period can be factored into any part of the day that suits you. For example, a 12pm-8pm time slot seems to be popular among intermittent fasters. This still allows you to eat main meals like lunch and dinner in the company of friends and family. With daily intermittent fasting, it's usually only a matter of cutting out one meal a day (eg breakfast) and then substituting it with bigger meals during the 8 hour period.
Alternate Day Intermittent Fasting:
This method of fasting encompasses longer fasting periods on alternate days of the week. This is where the rise of 5:2 comes from, more specifically it refers to eating normally 5 days of the week and then fasting on 2 non-consecutive days.
Fasting in this context means consuming a very low energy intake on the fast days, one small meal for example. This method takes a lot more time, planning and consultation. 24 hour fasting periods shouldn't be undertaken without first consulting a GP or health professional. Alternate day fasting or the 5:2 method has been proven to be just as effective weight loss tool as diets that restrict energy intake on a daily basis.
- Weight Loss: By allowing your body to regularly enter a state of ketosis, intermittent fasting is a reputable weight-loss tool.
- Inflammation: Inflammation is a key driver in many chronic diseases meaning intermittent fasting may pose as a solution for sufferers.
- Insulin Resistance: Intermittent fasting reduces insulin levels in the body and can reduce the body's resistance. A useful tool for people with type 2 diabetes.
- Cancer: Studies conducted on rats suggest that intermittent fasting may prevent cancer.
- Brain Health: As intermittent fasting changes the hormone levels of the body, it's shown to increase the BDNF hormone and may encourage the growth of new nerve cells. People who intermittent fast often say they feel sharper and more alert and this is why.
- Life-Span: Studies done on rats again showed that those who intermittent fasted lived longer than those who didn't.
Intermittent fasting is gaining popularity and for good reason. It functions as a viable and sustainable lifestyle pattern to lose and maintain weight levels. Before beginning any kind of fasting regime it's always advisable to consult a health professional first.
There are certain factors that prevent some people from fasting such as pregnancy, hormone levels or if you are underweight. Always incorporate fasting as part of a healthy, balanced diet and ensure you do additional research to find what method works best for you, everybody is different. While some may use intermittent fasting as a weight loss tool, others simply see it as an easier way to live with fewer meals to cook.