Intermittent fasting is one of the big nutritional trends of the last few years, but do you know the science behind it? As we move into the final week of January and people are still searching for the ‘perfect’ way to lose all the weight they intended to this year, I thought I’d delve into one of the world’s most popular health and fitness trends – intermittent fasting. It has divided the opinion of those working in the health and fitness industry. Which in turn leads many people to be confused on if it is worth doing at all.

Luckily, I am here to break down the science and let you make an informed decision on whether it will work for you and your lifestyle.



What is intermittent fasting?


Intermittent fasting is an eating pattern that alternates between cycles of eating and fasting. Unlike the majority of diets that tell you what to eat – intermittent fasting tells you when you should eat. It has gained popularity in recent years for its claimed health benefits. These include weight loss, improved metabolic health and cellular repair.

There are many forms of intermittent fasting. There is time restricted feeding (there is a 12-16 hours window each day to abstain from food, and allowing yourself to eat for the remaining 12-8-hour window).

The 5:2 diet which involves eating roughly 500-600 calories for two days of the week followed by five days of normal eating.

There’s also alternate day fasting (you would eat 500-600 calories one day and eat normally the next).

All these methods are based off the same idea. This is when you reduce your caloric intake, your body will use its stored fat for energy rather than glycogen stores which will be depleted during this time.

Even though this may occur, what really makes intermittent fasting different from simply just cutting calories is the possibility that it is easier for people to restrict calories for limited stretches of time. Rather than the days, weeks or months that may be required by other diets.



Intermittent Fasting; What the science says


The reason that there is so many conflicting opinions about intermittent fasting is because of the diversity of results in the studies that have been carried out. The hype around intermittent fasting became as a result of the promising research done on obese rats. The rats lost weight, decreased blood pressure and cholesterol and improved their blood sugars. However at the end of the day they are rats, not humans.

Even though studies in humans show that Intermittent fasting can be safe and effective, there is nothing to show that it is any more effective than any other diet or weight loss approach.

The idea behind fasting for weight loss is that when we eat after an extended fast, we don’t fully compensate for the food that we’ve gone without. This creates an energy deficit and results in weight loss.

Intermittent fasting ‘works’ well for weight loss simply because you eat less food.



Intermittent fasting; Things to consider


Is intermittent fasting something that you will keep up forever?

Will you never enjoy a drink out late at night for a relative’s party or enjoy an early morning iced latte and brunch again?

Most behavioural weight loss methods like intermittent fasting result in short-term weight loss followed by weight regain when you fall out of routine. Remember that a healthy lifestyle has benefits regardless of weight. Although intermittent fasting can work well for some people, it is simply not a magic bullet that will improve your health.

Women should take extra care if thinking about intermittent fasting. Although the research is still evolving and findings may not be applicable to everyone, it has been found that intermittent fasting can have negative affects on hormonal balance in women. It can negatively impact the menstrual cycle possibly due to the stress that fasting places on the body.

This can also negatively affect reproductive hormones. Finding a nutritious eating pattern that you enjoy and can stick with may be more beneficial for sustainable, long term health benefits.



In summary

In summary, it is important to understand the key factors around intermittent fasting, the science behind it and why it might not be dissimilar to other diets. At the end of the day, if you eat less you will lose weight! As always, you should consider long-term viability of any dietary practice. If you can keep it going long term and it works for you, then keep at it. If you don’t think you can sustain it long-term, maybe there might be an approach different to intermittent fasting that might be a bit better suited for you.


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