Is Intermittent Fasting Healthy? (What Does the Research Say?)

Intermittent fasting is a type of eating pattern that took the fitness industry by storm. There have been debates about the positive benefits that intermittent fasting can bring as well as the downsides. If you’re looking at implementing intermittent fasting into your routine, then keep reading to find out more about it.

What is intermittent fasting?

Intermittent fasting is an approach to eating that cycles between periods of fasting and cycled with windows of eating. It’s essentially a pattern in which you wait until you reach a certain number of hours fasted before allowing yourself to consume food and liquids.

Types of intermittent fasting

There are different types of intermittent fasting:


The 16/8 method is arguably the most popular. It consists of a 16-hour fasting period followed by an 8-hour window to eat and/or drink. This is a common way to intermittent fast as it can be simplified by just skipping breakfast and eating lunch and dinner as normal, as long as it’s within the eating window.

There is a rule that you can drink water or consume anything as long as it’s under 50 calories. This is essential as anything over this 50-calorie limit will take you out of the fasted state.


The 5:2 is slightly different. It involves eating whatever you want five days out of the week. For the remaining two days, you’ll be restricted to a limiting 500-600 calorie diet.


OMAD, one meal a day, is exactly what its name suggests. It’s when you only eat once a day with servings that are much larger than a typically sized meal. This one meal is when you fit in all your macro and micronutrients.

Benefits of intermittent fasting

Assists with weight loss

When we don’t eat after a period of time, our insulin levels drop. This then causes the body to use stored glycogen in the body to be used as energy. This means that the body doesn’t store fat but rather uses it as fuel, which can promote weight loss, making it a handy method for those with weight loss as their goal.

Can reduce consumed calories

As there is a smaller eating window allowed with intermittent fasting, it can mean that you may consume fewer daily calories. You won’t be able to graze or snack throughout the day if this is something usually done, or may have to skip the late-night meals. This can help those who are looking to manage their calorie consumption.

Reduces risk of disease

There are many health benefits that come with intermittent fasting. Whilst not conducted over the long term, this study has shown that short-term fasting can lower metabolic disease risk. 

It can also reduce total cholesterol and LDL cholesterol levels, as illustrated in this study as well as cardiovascular disease.

Risks of intermittent fasting

As with everything, intermittent fasting has its health risks.

Could increase binge eating

While it can prevent people from overeating due to a smaller eating window, it can also have the opposite effect and actually encourage overeating and binge eating. Because there is a short time to consume food and beverages, people may feel the urge to take in as much food as possible, leading to a binge.

Can cause dizziness and nausea

When you don’t eat for a long time, especially if it’s something that you’re not used to, you are more likely to feel lightheaded and dizzy. Your blood sugar levels will have dropped, also leading to dizziness. It can be disorientating and distracting. While some people get used to the fasting period, with these side effects fading, others’ may persist.

Who can and can’t do intermittent fasting?

Despite being proclaimed as a life-changer by those in the health and fitness industry, not everyone can or should intermittent fast. It may do them more harm than good. These people include:

  • Pregnant/breastfeeding women
  • Those with a chronic disease
  • Those who are underweight and have high caloric needs
  • Children

The best way to know if you’re suitable for intermittent fasting is to give it a go yourself as long as it’s safe to do so. Firstly, ensure that you’ve been cleared to do so by your local GP. Be aware, there may be an adjustment period that can last from a few days to a couple of weeks.

Intermittent fasting is a structured eating plan that can deliver an array of weight loss and health benefits. However, proceed with caution as it can do more harm than good.

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Emily Trinh