Intermittent fasting

Intermittent fasting is growing in popularity at the moment as a way to lose weight. What’s attractive about this diet to many people is that it doesn’t focus on what you can eat. Instead, it’s designed around when you can eat. Here, our resident nutrition expert, Stephanie Yu, explains more.


The Harvard School of Public Health defines the diet as “a diet regimen that cycles between brief periods of fasting, with either no food or significant calorie reduction, and periods of unrestricted eating.”


Unlike other diets, intermittent fasting offers some flexibility around fasting windows. It also has the benefit of not restricting what you can eat. Some people will fast for a day or two per week and eat regularly on the other days. Others might prefer a time restricted approach, eating their meal by 8pm and not eating again until around lunchtime the following day. 

Some people may experience benefits including weight loss while others may not see much of a difference, or find that they feel too hungry to participate in fasting or that it impacts them day-to-day. Everyone is different, and it’s recommended that you speak to your doctor or a health practitioner like a nutritionist for advice before trying it out for yourself – especially if you have a medically diagnosed health condition. 


Trials have compared people that are having a diet where they eat normally with people who participate in intermittent fasting, which found that it can improve your blood sugar control, specifically seeing a decrease in fasting blood sugar. Those who fast, saw a decrease in the blood sugars and an improvement in insulin resistance, meaning their body was more responsive and more effective in converting blood sugar into energy. Similarly, other studies have compared groups of people who fasted intermittently with groups of people who dieted by reducing their calorie intake. The findings indicate that fasting may be more effective in terms of body weight loss.


Many claim that it’s a more sustainable diet for them to follow – they’re less likely to drop out or rebound, because it’s easier and they are able to enjoy a lot of their favourite foods openly and without guilt. 


Some people do intermittent fasting for other reasons, such as to reduce inflammation in the body. At this stage, the most research around fasting is focused on weight loss, with limited studies completed regarding the benefits of it for reducing inflammation. A 2007 study suggested it may improve Irritable Bowel Syndrome (IBS), however there are also studies – such as this one – that suggest it does not affect any inflammatory markers. If fasting has been working for you for this reason, this may simply be because you are not eating the food or foods triggering your symptoms due to eating in restricted timeframes. 


It’s clear that there are plenty of benefits, but it’s important to remember that fasting doesn’t work for everyone – and it’s not recommended for some people. 


What are the myths of intermittent fasting

Like anything, there are plenty of myths and misinformation out there about intermittent fasting. This is largely due to the fact that research into fasting is still ongoing with no definitive answer about whether or not it works. 


Myth #1: you can eat as much and whatever you want during non-fasting periods

Many people believe that this is true and that they will still be able to lose weight or see positive effects from fasting. Unfortunately, it’s simply not true. It all boils down to calories in vs. calories out. As a reminder, women are should aim for a daily calorie intake of 2,000 and men for 2,500. Be careful not to go too far over this during your non-fasting periods by eating too many foods high in saturated fats. 


Myth #2: intermittent fasting is more effective than calorie restriction for weight loss

While there is some research out there that suggests intermittent fasting and calorie restriction is similar in terms of effectiveness in helping someone lose weight, it is not as effective. The most effective way to lose weight is through combining a balanced diet, reducing your calorie intake and participating in regular exercise. 


Myth #3: I’ll definitely lose weight if I start fasting

You might feel less bloated as a result of fasting, but it’s important not to mistake that for weight loss. Intermittent fasting is not for everyone. People with diabetes shouldn’t fast as eating at regular intervals ensure they blood sugar doesn’t fluctuate too much. Other individuals who shouldn’t fast include pregnant or breastfeeding women or people taking medication with food. Researchers have not reached a definitive conclusion around the impact of fasting on your thyroid, but it is believed to alter your thyroid hormones and therefore, there may be risks for people with thyroid-related diseases. 


Myth #4: intermittent fasting will slow down my metabolism

If we look at your general metabolism, intermittent fasting has no significant effect on altering it, and it will not increase your resting metabolic rate. If you fast intermittently, fat oxidation levels will be higher during your fasting periods as your body burns more fat to produce energy in the ketosis state. The results and long-term effects will differ from person to person, so speak to a professional before you decide to get started. It’s widely known that prolonged periods of low-calorie diets can change the body and prevent further weight loss. Intermittent fasting is believed to address this, but research on is not conclusive. Prolonged fasting could trigger your hormone production and there is a chance that your body may produce less of the hormone that makes you feel full (leptin), which could lead to you eventually overeating. 


Myth #5: intermittent fasting means I don’t have to exercise

The main reason why intermittent fasting works better for weight loss is because people have less hours to eat in general. This doesn’t mean you can’t – or shouldn’t – exercise. Exercising alone can help you lose weight more than just calorie restriction. You just need to try and find the exercise that works for you. Exercise not only helps you to stay fit but it also keeps you healthy by improving blood sugar control. It can also reduces the risk of chronic disease such as heart disease and stroke. 


Myth #6: I can still drink liquids during fasting periods

Liquids are fine to drink during fasting periods – but not all liquids are the same. Hydration is essential for your body’s proper functioning. While water is the best way to hydrate, a herbal tea or black coffee can help curb food cravings while fasting. Beware of smoothies or protein shakes as these can have a surprising amount of calories and high sugar content. This defeats the purpose of fasting and leads to increased calorie intake. It also goes without saying that you should not drink alcohol during your fasting period. Drinking alcohol on an empty stomach in never a good idea.


What happens to your body when you fast

When you fast, your body uses glucose (blood sugar) as a food for energy. When the body has exhausted that glucose, it starts burning fats for energy instead. This is what can lead to a loss in body weight. In extreme cases, this can lead to your liver’s production of ketone bodies. Too much ketone in your body can be harmful and symptoms of this include tiredness, feeling nauseous or stomach pain. 


At the end of the day – and it might sound cliche – the best thing you can do to lose weight and stay healthy is to eat at regular intervals and exercise daily. One of the most popular forms of fasting we’ve seen among Mood Active participants is to skip breakfast. When you don’t eat breakfast, you tend to eat a lot of high calorie foods. Breakfast is an important meal to kick-start your day however it doesn’t mean you have to go all-out. Research shows that breakfast should actually be a small meal. We recommend incorporating a protein source – particularly if you exercise in the mornings or if you are diabetic. 


Some simple breakfast ideas:

  • A banana with a glass of milk
  • Some wholegrain or healthy seed crackers with cheese
  • One slice of toast with your favourite spread
  • Some blueberries with yoghurt and seeds
  • A poached or hard boiled egg


Beware of shakes and smoothies, especially if you are overweight or obese as you can easily over consume them, adding too much sugar to your diet. When it comes to breakfast, it’s best to eat something rather than drink it. As for lunch and dinner, think about a balanced plate that incorporates a decent amount of vegetables, an adequate amount of meat/protein and carbohydrates, and some fruit into each meal. 


If you’re struggling with your motivation to exercise, Mood Active offers affordable exercise programs with the extra outreach, coaching support and supervision you might be looking for. Contact us if you’d like to learn more.


Stephanie Yu holds a Masters in Nutrition and Dietetics from the University of Sydney. She also has a Bachelor’s degree in Food, Nutrition and Health.

Cover Photo by Morgan Sarkissian on Unsplash