Intermittent Fasting is a highly debated topic, and I'm tipping most trainees and gym goers are confused of exactly what it is and whether or not it will work for them.
The goal of this article is to explain what Intermittent Fasting is, present the positives and negatives of using this way of eating and finally discuss why it doesn’t work for everyone. I will then give some super simple examples of effective ways you can introduce some basic intermittent fasting principles to assist with your fat loss goals.
What is Intermittent Fasting?
Intermittent Fasting (I-F) is simply the practice of altering meal timing and frequency so that you eat your meals within a reduced time period causing you to fast for longer than normal intervals while maintaining a similar caloric intake. The length of the fast interval and eating window will depend on the I-F Protocol that is used.
I-F examples include 16-8 where you fast for 16 hours each day and eat all of your meals in an eight hour window. This could mean that you eat dinner at 6:00pm and don’t eat Breakfast until 10:00am the next day. The fasting lengths can vary with other examples including 24, 20, 14 and 12 hour fasting windows.
Everyone does some form of fasting, by simply not eating in between meals, the longest fast being overnight when sleeping, hence the term ‘Breakfast’ simply means to break the overnight fast.
The Good Aspects of I-F
People who practice IF get too eat less frequently, which in turn allows them to save time as they do not need to spend as much time eating. However they most likely will not save money as they will generally eat the same amount of total food but just in a reduced time frame. Some models of I-F do promote a reduced caloric intake as you are eating less frequently, but this article will focus on modifying meal timing for fat loss, not necessarily the amount of food consumed.
The health benefits of I-F include:
improved insulin sensitivity. During a fast your body becomes more receptive to carbohydrates and is more likely to use them to refuel muscle glycogen and for energy rather than be stored as fat.
Fating increases the release of growth hormone (GH) which will up regulate the use of fat for fuel and help spare muscle glycogen stores. This can lead to accelerated fat loss in some individuals.
Along with the above positive aspects we also see long term benefits of:
-Lower cholesterol and blood pressure
-Reduced DNA damage and risk of cancer
-Increased cell repair and appetite control
-increased body fat loss, overall better health and greater longevity.
At this point your probably planning out your intermittent fasting schedule, ready to get straight into it because it seems like a flawless plan to fat loss, health and vitality, Right? Maybe not, and heres why.
The not so good aspects of I-F
It can lead to you losing that hard earned muscle
I-F should be used or fat loss and fat loss only, but a consequence of not eating for extended periods of time can mean you become catabolic. This means your body can and will use muscle for fuel.
Your training will suffer
Some intermittent fasting protocols boast an increased benefit if you workout during your fasting period and then eat your first meal after training. How do you think you will feel training after not eating for 15 hours? This may be ok if you are doing a quick HIIT program but if you are weight training, which we hope you are, training in a fasted state can be detrimental to your performance and your results.
Males v.s Females
The research shows that Intermittent fasting can work well for Males but not really for females. 80% percent of females (40 % of the entire population) will not respond well to a lack of food for extended periods. Many women find that with intermittent fasting comes weight gain, blood sugar imbalance, sleeplessness, anxiety, irregular periods along with a bucketful of other problems involving hormone dis regulation.
Studies have found that unlike men, women don’t always experience increased insulin sensitivity, and that glucose tolerance can actually be worsened by I-F protocols. (1)
As for the males, it will work for some, but not others. Why?
This is because your hormones need to be functioning optimally to take advantage of I-F. If you're accustomed to a high CHO diet, or are chronically stressed and your body isn't efficient at burning fat for fuel, intermittent fasting may just be an extra stressor on the system, jacking up your cortisol, making you fatter, angrier and less pleasant to be around.
If you are chronically stressed (you may be and not even know it) your cortisol levels are already through the roof, so going extended periods without food is just going to stress you out more, leading you to most likely gain fat and waste muscle tissue.
Another point worth mentioning is that IF protocols aren’t recommend for individuals with a history of eating disorders, as going long periods without eating could easily lead to binge eating during your ‘feasting window’ and could be the start of other nasty eating habits.
So, what now?
So if your female and thinking about trying some intermittent fasting, there is better, safer ways to drop some unwanted body fat.
Start by consuming a high protein, high 'smart' fats breakfast everyday and ensuring every meals has a good source of protein (meat or eggs).
Aim to eat 5-7 meals per day and not to snack.
For males, intermittent fasting can a useful fat loss ‘tool' to add to your tool box.
Before beginning any kind of Intermittent Fasting you should be nailing all your meals consistently, eating meals of high quality whole foods and training regularly. I-F isn’t just an excuse to be lazy, skip meals, eat less and eat poorly.
Also a lot of I-F protocols propose that you skip breakfast all together and just have a black coffee to get you through until lunch. We like to think of it as you are having a late breakfast, so instead of having breakfast for example at 6am your having it at 8am or 10am depending on the protocol you use.
At CTS we don’t regularly use I-F with our clients, however for short periods we may introduce a change to stimulate some extra fat loss. Some example include the following:
If your new to intermittent fasting studies have shown results with a simple approach of not eating for 12 hours during every 24 hour period. This is as simple as eating your dinner at 7pm and not eating breakfast until 7am.
For further benefit you could try eating all your meals within 10 hours and not eating for 14 hours each day. This means having dinner at 6pm each day and not eating anything until 8am the next morning.
Another super simple strategy is too not eat anything within four hours of going to sleep. This strategy can be safely used by both men and women. For example if you go to sleep at 10pm, eat your dinner at 6pm and don't eat anything else until the morning. Doing this every second day should get you some good results, no extra benefit has been seen from doing it every day compared to 3 days per week.
Take away Points
I-F can be a useful tool for males to help stimulate some extra fat loss.
I-F has only been shown to be beneficial to 20% of females, so females are better off finding safer ways of eating. A very basic form of I-F that is suitable for females, minimising risks is simply to not eat with four hours of sleeping every other day.
Extremes of any way of eating are generally not the answer, but simple I-F protocols such as 14-10 can be very effective.
Eat smart, stay healthy.
1. Krista A Varady and Marc K Hellerstein, Alternate-day fasting and chronic disease prevention: a review of human and animal trials1,2,3. The American Journal of Clinical Nutrition.