One diet trend that has gained popularity recently is intermittent fasting. Along with weight loss, it has been touted for reducing chronic disease risk, improving sleep and even slowing down aging – so should we all jump on board right now? Not so fast.
WHAT IS INTERMITTENT FASTING?
Intermittent fasting sets itself apart from other diets as it focuses more on when rather than what you eat. The basic premise is an eating pattern that rotates between periods of not eating/eating very little (fasting) and ‘normal’ eating.
THE TYPES OF INTERMITTENT FASTING
The three common fasting methods are:
Time-restricted [e.g. 16:8]– eating meals within a designated time frame each day e.g. 8-hour eating window, 16 hours fasting
Whole Day [e.g. 5:2] – eating less than 25% of your daily energy requirements (~500-600cal) for two non-consecutive days and usual eating for the other five days
Alternate Day – eating less than 25% of your daily energy requirements (~500-600cal) every second day
A major reason why people try intermittent fasting is to lose weight and the good news is that it may help with this. Having specific eating/fasting periods may allow some individuals to develop a better understanding of their body’s hunger and satiety cues and assist in reducing mindless snacking e.g. late-night munchies. For some, this eating pattern is more mentally appealing as they don’t have to “diet daily”.
However, it is important to note that current research has shown no significant difference in weight loss achieved through intermittent fasting in comparison to a standard calorie reduction approach. Intermittent fasters will usually lose weight because their overall energy intake is reduced (as with most diets) – not because fasting is some kind of special magic trick! In some animal studies, fasting has been linked to improvements in gut health and risk factors for chronic disease (e.g. diabetes, heart disease, cancer). Whilst these benefits highlight fasting as an exciting and potentially promising area of nutrition research, the results can’t be generalised to humans.
Instead of intermittent fasting, using a low-calorie diet could have a similar effect. For example, using KicStart to replace some (or one) of your meals.
Ever been hangry (hungry + angry)? If you’re going without food for long intervals of time, it is not surprising you might start to feel irritable, fatigued, headache-y and have difficulty focusing on daily tasks and performing at your peak. Maintaining your usual exercise routine (and not to mention, your social life) may be quite a challenge on your fasting days!
Your overall diet quality may not be improved since intermittent fasting doesn’t focus on what foods you eat or making healthier food choices and it can be a real challenge to get in enough essential nutrients in a shorter time frame/smaller number of meals.
Fasting is not a one-size-fits-all and is not suitable for certain individuals e.g. people with eating disorders, diabetes, pregnant women or those who use medications that need to be taken with food.
THE FINAL WORD
At this stage, no conclusions can be made about whether intermittent fasting is a superior method for weight loss or disease prevention – better and longer-term human studies are needed. If you are thinking of fasting, please chat with your doctor and/or dietitian beforehand. For lasting long-term health benefits, remember that the best diet is the one that is sustainable over time and suits you individually!