Intermittent fasting – yes or no?
Intermittent fasting (IF) has become increasingly popular due to its claims about weight loss, cognitive sharpness and cellular regeneration. While IF can work really well for some people and I’ve seen some clients reach their weight loss goals adopting it, unfortunately it is not a magic bullet to improved health. This week I’m going to share the facts on IF to help you decide if this is a lifestyle habit you want to choose to adopt.
What is IF?
IF in general terms is an approach to eating that alternates between periods of fasting and eating. There are different ways to do IF, but the most common are 16/8 (eating only during an 8 hour period followed by a 16 hour fasting window) and the 5:2 diet (choosing 2 days a week where <800kcal are eating and eating normally on the other 2 days). There really are endless variations to fasting and one is not better than other – the best type is the one you can stick to.
Does IF help with weight loss?
Most often then not – yes. But not for any magical reason. In simple terms, if we are restricting the hours in the day where we are able to eat, we are likely going to eat less total food/ energy in the day which will result in weight loss. If you are doing IF and not losing weight, this just means you are meeting your energy requirements throughout the day in the shorter time-frame.
What about all the other benefits to IF?
There is definitely growing research around the benefits to IF including decreasing blood pressure, improving cholesterol and reducing inflammation. However we don’t know for sure if these health markers are due to the fasting or the weight loss.
Another benefit is something called autophagy, a cellular process where damaged or unnecessary cells get degraded and new, healthier cells are regenerated. This process gets slower as we get older, so fasting can be of greater benefit as we get older. Unfortunately a lot of the research on this process is from animals instead of humans so we don’t know exactly how long someone will have to fast to get these benefits.
So, should I do IF?
If your goal is weight loss, and you find yourself often snacking through the late hours of the night or just eating large portions of food in the evenings, it might be helpful to set a time in the evening to brush your teeth and stop eating till the next morning (aka fasting).
If you’re someone who is underweight, has a history of disordered eating, <18yo, taking diabetes medication, undergoing cancer treatment or pregnant/ breastfeeding.. IF is not recommended for you due to potential risks associated with undereating or time-restricted eating.
Additionally, as hunger is a main side effect of IF, you may also feel weak and your brain may not perform as well (although this can change over time as your body adapts). If this doesn’t change – there is no reason to put yourself through IF. There are many different ways to achieve healthy and sustainable weight loss outside of fasting and it is absolutely best to find an eating pattern that you enjoy and can stick to!
