The fasting debate has been going on for a while now with the 5:2 diet gaining a great deal of attention in recent years. Now, we’ve moved onto intermittent fasting, with hundreds of varieties of both the 5:2 diet and intermittent fasting its all becoming far too confusing to put into practice. Do the benefits out weigh the negatives? Is it really worth planing your food intake times? Will it affect your social life? I’m here to clear things up once and for all. Having read a lot into the science behind the different varieties of fasting diets I’ve set out to explain them.
This method gained a lot of popularity due to the work of Dr Michael Mosely. However, is it really all it is set out to be? What does it mean? How do we do it? And is it really worth it? The 5:2 diet involves you ‘fasting’ two days a week. Although, this does not mean you have to abstain from food completely it just means you significantly reduce your calorie intake. It is recommended that females consume 500 calories a day and males 600 calories. Whilst the results of this mean that you have a significant calorie deficit within that day, research has suggested that on the ‘feed’ days individuals only consumed 115% more than they would normally which means per week you are still left in a calorie deficit. Now whilst I am strongly against the idea that calories are the be all and end all I think it is essential to make informed and good food choices for the fast days. I recommend eating foods high in healthy fats, proteins and complex carbohydrates. Eating simple carbohydrates (typically high sugar foods) will spike your blood glucose levels, your insulin levels and make you hungrier quicker which will mean you’ll find the fast more difficult. I also recommend spreading your intake out throughout the day to maintain that balanced blood glucose although, this is definitely something which you have to assess yourself and see what works for you. The 5:2 is more likelyto affect your social life as you have to plan your fast days well in advance and it is not recommended to do them back to back.
In this method you are required to fast for 16 hours of the day and eat during an 8 hour period. There is no calorie restriction in this theory and it is often referred to as an eating pattern rather than a ‘diet’ (although I don’t agree with that word either!) This is the most realistic and easiest form of intermittent fasting as it simply requires you to skip breakfast, have lunch and a slightly earlier dinner. For example finishing eating at 8 and begin again at midday. It is also less likely to impact your social life. Research suggests that this may help to improve insulin sensitivity and cell repair. However, more research is required to confirm this.
This is the more extreme version of intermittent fasting, it requires you to go for 2-days a week with no food or calorie containing drinks. This method is more likely to impact your social life and requires even more planing than the 5:2. Once again it is not recommended that you fast on two consecutive days.
It is all very well understanding the differences in these methods but what are the real benefits of restricting our feeding time and or the amount of food we are consuming?
Some research suggests that intermittent fasting can improve insulin sensitivity which helps to reduce the risk of type 2 diabetes, reduce inflammation, aid weight loss, improve cholesterol and promote delayed aging.
So whilst this all sounds fantastic and potentially the answer to all your nutrition questions and issues is it really all it is laid out to be?
This is a very new area with not many studies and as a result there may be other ways of fasting but there is no research to back these up. Some studies suggest that the weight loss is merely glycogen and water depletion however, we are all different and not everything works for everyone. Alternatively it may be that weight lost on an intermittent fasting diet may be due to significantly reduced calories. As mentioned this is something which could impact your social life and more specifically I think it is essential to consider the impact of restrictive feeding on your mental health. Often restricting yourself from eating can lead to other psychological problems down the line. Overall, I'm not saying that intermittent fasting is terrible, I'm simply suggesting that a lot more evidence is required before we get over excited and jump on the band waggon and to be aware of the impact it may have on your social life and mental health in the long term.