In this post we're going to discuss the role of intermittent fasting to facilitate weight loss including the science behind intermittent fasting, how it works in practise, side effects and tips for what you could eat and also foods to try and avoid.
Before we get into the main section of the post I do want to stress that I've designed this as a general educational resource. It's not a clinical advice article and I'd strongly suggest that if you do have a medical condition such as diabetes and you're thinking about making changes to your diet you should first discuss this with your healthcare provider especially if you're taking medication.
What is Intermittent Fasting?
So let's start the post by discussing what intermittent fasting is. Well put quite simply intermittent fasting involves cycling between periods of fasting and eating and there are two main ways of doing this in practise and we'll discuss these in more detail later in the post, but in a nutshell when you fast you use up stored energy by burning excess body fat and this results in weight loss.
Science Behind Intermittent Fasting
Now that we have a basic understanding of what intermittent fasting is why don't we briefly look at the science behind intermittent fasting, because I do think that it's worth trying to understand what the theory behind intermittent fasting is to try help us make sense of how this particular form of dieting help us to lose weight.
When we eat we take in more energy from food than can immediately be used by the body. A hormone called insulin is produced when we eat which breaks down carbohydrates into glucose. Glucose can then be used by the cells for energy or it can be stored in the liver or muscle as glycogen.
When we need a quick source of energy or the body's not getting glucose from food the glycogen is released from the liver and broken down into glucose and sent into the bloodstream.
However there's limited storage space for glycogen and once stores are full the liver will turn excess glucose into fat, some of this fat will be stored in the liver or it will be exported to other fat deposits in the body.
Now when you fast the insulin levels fall, this signals the body to start burning stored energy and one of these stored energy sources that the body can use is glycogen in the liver and the body will use that first as it's most accessible.
After the glycogen has been used up the body will start to break down fat to get the energy that it needs. If we start to burn the stores of energy such as the glycogen or our accumulated fat then in theory we should lose weight.
How to Loose Weight with Intermittent Fasting
Now that we know a little bit more about the science behind intermittent fasting. Well what are the different methods for fasting if you want to loose weight? Well the two most well-known methods for intermittent fasting are the 5/2 diet. This is where you normally eat for five days a week then eat only around 500 to 600 calories on the other two days.
The second option is time-restricted eating where you have a long period in the day when you don't eat. With the time-restricted eating most people choose something called a 16/8 cycle. This involves not eating for 16 hours of the day then having an eight hour eating window and generally this diet form is done daily or almost daily.
Intermittent fasting can help you lose body fat as it works out to approximately a 25% total calorie deficit for the week. However you do need to be mindful of what you're eating in the fed state. If you overeat or you're eating high calorie foods then you won't see the weight reduction that you're looking for.
Food to Consider When Performing Intermittent Fasting
So now we know a little bit more about the two main practical methods for intermittent fasting why don't we look at five foods that you might want to consider incorporating into your diet and also five foods to try and avoid. So for the days and times that you're not fasting you're going to keep your diet in line with general health eating guidelines and to help you with this I'm going to highlight some key food groups that you might want to consider.
1. Whole Grains
The first are whole grains these come under your starchy carbohydrates and these will provide slow release of glucose into the bloodstream. They're also an important source of fibre, vitamins and minerals and examples of these are oats, whole grain bread, whole grain pasta as well as brown rice.
2. Lean Meat
The second food group is lean meats and fish and these are important because they're packed full of protein and this is essential for the growth and repair of muscles and tissues. The best kinds are lean meats such skinless chicken and low-fat turkey.
White fish such as haddock or cod are lean sources of protein and oily fish like salmon, sardines, tuna, mackerel they're full of omega-3 fatty acids which are important for brain and heart health.
3. Dairy Products
Now the third food group to consider are dairy products which can be a rich source of calcium which is really important for bone health but you should try to choose low-fat varieties of dairy products things like skimmed milk and low-fat greek yoghurt.
4. Fruits and Vegetables
The fourth group are obviously fruits and vegetables these provide us with an important source of vitamins, minerals as well as fibre.
5. Lentils and Beans
Finally lentils, beans and pulses are also good because they're low in fat and they're an important source of protein, fibre as well as vitamins and minerals.
Now those are the five food groups that I think you should try and incorporate into your diet but some people will ask well what foods should I avoid?
Foot to Avoid if you Want to Loose Weight with Intermittent Fasting
1. Well on an intermittent fasting diet foods that you should avoid are things like refined carbohydrates, this means carbohydrates that have been highly processed and they contain little of the original grain and this is important because these foods are going to cause a rapid spike in your blood glucose levels and these are things like white flour, white bread, white rice, white pasta, many breakfast cereals they're usually packed full of unrefined sugars.
2. The next one is obviously sugar and this includes simple sugars like table sugar, maple syrup, foods that contain added sugar things like sugary drinks, sweets, chocolates, ice creams and biscuits.
3. The other food group to try and avoid are complex animal fats these are things like dripping and lard and these should be avoided on a low-fat diet because they're high in saturated fat.
4. You should also try avoid too much red or processed meat so meats like bacon and sausages these contain lots of saturated fats and try stick to lean meats or try to cut any visible fats off if you're eating meat.
5. Finally processed foods these are foods that have been altered in some way during preparation things like cakes, pastries and biscuits as well as pies and convenience foods they tend to be high in calories due to the amount of saturated fat as well as added sugar.
Side Effects of Intermittent Fasting
So what are the possible side effects of an intermittent fasting diet? Well some people might experience headaches and constipation but the risk of this can be minimised by making sure you're drinking plenty of fluids on the fasting days as well as eating plenty of vegetables and fruit.
Again I do want to stress that if you're considering the intermittent fasting style of dieting then please consider this in the risk of your own personal health and medical conditions and if you've got any questions or concerns before starting this diet then please do try to speak to a trained and registered dietician or your doctor who will explain to you on the sustainability as well as suitability of this in relation to your own personal medical history.
Conclusion
So that brings us to the end of this post I hope you enjoyed it as well as learned something new and if you did please remember to consider subscribing to our blog. If you've got any other thoughts or you want to share your experiences with intermittent fasting both positive and negative, do in the comment box below.