23 Jul 2018
Intermittent fasting is the practice of restricting your eating over a specific period of time. It is often used as way to lose weight or boost energy levels.
These schedules are often called 'cycles'. They're made up of windows of time when you avoid eating entirely, and others where you can eat normally. Perhaps the most famous 'cycle' is the 5:2, also known as the 5:2 diet. In this schedule, you eat normally for five days of the week and limit your calorie intake significantly for the other two days.
However, there are many other variations, including the 16:8 cycle (16 hours of fasting and eight hours of eating per day). The exact schedule a person uses is often tailored to their specific needs, based on their lifestyle and job type. Intermittent fasting is used by athletes and fitness enthusiasts, as well as people who are trying to lose body fat.
As a method of dieting, fasting has proved quite controversial. Some people rave about its ability to take inches off your waist and boost your energy levels. Others, though, have accused intermittent fasting of being a fad diet. Concerns have also been raised over its long-term health implications.
With any new health trend, there's always a deluge of (often conflicting) information which can make it hard to evaluate. Sometimes, the best thing to do is to try these things for yourself. An even better option is to read an article about someone who has already done it!
To that end, our intrepid colleague Louise agreed to try intermittent fasting for a month and report back with her findings. We'll go into Louise's thoughts on fasting a little lower down, but before that, let's take a look at what the latest scientific research says..
In one academic study, published in JAMA Internal Medicine in 2017, 100 participants, all medically classified as overweight, were each assigned one of three eating regimens.
Some participants were put on what we might call a 'standard diet', involving straightforward calorie restriction. They were allowed to eat at any time of day.
The second set were told to alternate fast days. In this schedule, they'd have one fast day followed by a day of normal eating, followed by another fast day, and so on.
The third set were told simply to follow their normal daily eating habits.
Researchers conducted the study over a 12-month period, and the results are as we might expect.
Arriving at the end of the study, both restricted participant groups had lost weight compared with third, non-restricted group. However, the intermittent fasters did not lose more weight than the regular calorie cutters.
Whilst this is only one research study, it seems to show that for weight loss purposes, intermittent fasting is effective. However, it's no more effective than the regular calorie-restricted diets which have been common practice for many a long year.(1)
Other academic research studies have identified patterns between enhanced brain function and fasting.
It is vital to note that much more research is required before this hypothesis can be confidently confirmed, but there are a number of promising results.
Mark Mattson, a neuroscientist and researcher at the National Institutes of Health, has researched why food deprivation might actually increase our energy. He suggests that a variety of evolutionary factors might be behind our boosted energy and enhanced focus when we're feeling peckish.
Hunger, he says, is an evolutionary reality we need to be able to deal with. When we're hungry, it's the worst possible time for us to feel sluggish and tired; rather, we need to get up and about to find a source of food.
"It makes sense that the brain needs to be functioning very well when an individual is in a fasted state because it's in that state that they have to figure out how to find food," Mattson told Business Insider. “They also have to be able to expend a lot of energy. Individuals whose brains were not functioning well while fasting would not be able to compete and thrive.”
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