There is an abundance of diets, some more popularized than others. For example the Atkins diet has been heavily popularised in mainstream media throughout the world, particularly in the 1960s in the West when food culture started changing and people started gaining excess weight as a result of this. Particularly in the United States, a large focus began to shift onto how to lose weight and stay slim, hence the beginning of the diet revolution.
A ‘diet’ by definition is a special course of food to which one restricts oneself, either to lose weight or for medical reasons according to the Oxford Dictionary. So in essence, a diet is an eating habit with its aim set as weight loss. There have been periods in the diet revolution associated with particular diets, for example the Atkins diet in 1960s, the Weight Watchers diet in the 2000s etc and the Ketogenic diet in more recent times.
But how effective are diets? Diets, as a tool for weight loss, have mixed results. People who are more able to adhere to the diet, will in most cases successfully lose weight. Whilst conversely, individuals who have poor adherence are more likely to maintain their weight or in some cases increase their weight. Those who are unable to adhere to the diet often cite negative emotions such as feelings of failure, increased hunger and more mood swings.
This is not just unique to those who fail to stick to the diet though, in fact even those who successfully lose weight cite a combination of negative feelings associated with the diet plan. Doesn’t sound too good does it? So how can you lose weight effectively and enjoyably? The jury is out. Some tout intensive exercise as the best fat loss method, but you’d have to run a lot of miles to burn off that cheeseburger. It’s all about what you’re putting in your body, and as scientific research has more recently discovered - when you’re putting it in your body.
What Is Intermittent Fasting
You may have heard of various forms of intermittent fasting - the 5:2 diet, the time controlled eating diet, the 16 hour window diet etc. These are all under the bracket of intermittent fasting, and from now onwards I will refer to them not as a ‘diet’ but as an eating pattern, because that is essentially what it is.
Unlike a typical ‘diet’, intermittent fasting does not give guidance on what you should be consuming, only when you should be consuming it. It is fundamentally based on the concept that historically humans do not ‘graze eat’ i.e. eating continuously throughout the day and evening; and this can in fact be detrimental to your digestive system.
Historically, humans were hunter gatherers who would go through long periods of famine often during the winter when there were few crops or when there were no animals to kill for sustenance. After a prolonged period of famine, they would enter a feasting period in which they would consume a large meal shared with their tribe. This cycle would then repeat itself.
When you compare this with how humans eat today it could not be more different. We live in a fast food culture: calorie dense food is highly accessible, cheap and palatable. It is common for most to eat upon rising and continue eating every couple of hours until sleep. This eating pattern can cause overeating, due to the extended eating window which can lead to an increased appetite and food cravings. This can then lead to weight gain and obesity.
Alongside the increased risk of obesity, eating continuously throughout the day can wreak havoc with your digestive system. It can take anywhere between six to eight hours for your body to properly digest the food you have consumed. So think about it this way - if you are snacking until midnight and then wake up at 8am and eat breakfast, it is likely that the food you ate the night before has not even been properly digested yet. In extreme cases, this can cause liver toxicity, irritable bowel syndrome (IBS), bloating, inflammation and other undesirable health issues.
What Happens To Your Body When You Fast
Fasting has been shown to improve biomarkers of disease, reduce oxidative stress, preserve learning and memory functioning, increase muscle mass and reduce body fat - according to recent research undertaken by the US National Institute of Health (1). This of course depends on a plethora of variables aligning, for example if you are eating large quantities of junk food more so than usual, you will not experience these benefits. However, if you are eating a healthy balanced diet, get sufficient exercise and commit to the time frames of the fasting and eating windows - you will start to notice some of the amazing benefits of intermittent fasting.
The most common form of intermittent fasting is the 16:8 fast, which involves fasting for 16 hours typically during the night time until around midday and then eating until the evening. Essentially you’re cutting out breakfast. This has been shown to suppress the appetite and decrease stomach capacity, which causes feelings of satiety to occur sooner into eating thus resulting in a smaller food intake. So for individuals that are trying to lose weight, fasting can be a great tool.
There are several theories about why fasting provides physiological benefits, one hypothesis being that cells are under a moderate level of stress during a fasting period. This results in cells being forced to adapt by improving their ability to manage stress and resist disease. Studies undertaken by the US Institute of Health have shown a similar physiological response when an individual is undertaking intense exercise, in which the cardiovascular system is under a similar level of stress. The body responds by effective adaptation, similarly to what occurs during intermittent fasting.
Now going back to the initial point of question, intermittent fasting is not a diet. It is not similar to the Atkins diet or the South Beach diet on the basis that it does not state what y ou should eat, only when. This does not mean you are able to gorge on high calorie treats all day and expect to lose weight as long as you’re fasting. But it does mean that you have flexibility in what you decide to eat, which has been shown in numerous studies to increase adherence to losing weight.
You will also notice having a decreased appetite which will help you to reduce your caloric intake leading to weight loss. All you need to do is fast for 16 hours a day, eat for 8 hours a day and be as healthy as you can. No absurd restrictions, no mood swings or negative thoughts, just a simple shift in your eating pattern.