What is Intermittent fasting? Is it superior for weight loss compared to other diets? What are the actual health benefits of intermittent fasting? It’s a popular topic that we often get asked about so in this article we’re going to break it down and clarify if, how and when intermittent fasting actually works.
Firstly, what is intermittent fasting?
Intermittent fasting (of some sort) has been around for hundreds of years as part of different cultures and religions – or maybe just because food sources were scarce. The basic premise of intermittent fasting is an eating pattern that cycles between periods of fasting (not eating) and periods of eating. Unlike most diets It does not dictate what you can and can’t eat, but rather when you should eat them. In this sense, it is more like a pattern of eating rather than a ‘diet’.
What are the various types of intermittent fasting?
All fasting diets require you to restrict your usual energy intake and go for extended periods without foods, but there are differences amongst the popular approaches that you need to know about:
- 5:2 Diet: one of the most popular methods of intermittent fasting involves a ‘normal’ healthy eating days for 5 days a week and ‘fasting’ for 2 days a week. On the ‘fasting’ days the aim is to eat one-quarter of your usual meals, which is around 2100 – 2500 kJ (or 500-600 calories). Fasting days can be consecutive or separated throughout the week.
- 16/8 Method: involves restricting your meals to an 8-hour window each day (e.g. 12pm – 8pm) and fasting for 16 hours.
- Eat-Stop-Eat: involves fasting for 24 hours, once or twice a week.
Does intermittent fasting result in weight loss?
It’s likely, but not definite. Before you jump to conclusions and join the intermittent fasting bandwagon – it’s important to understand why.
The reason people who fast intermittently will usually lose weight is because they are eating less kilojoules than they were before – not because of the fasting per se. In fact, this is why most ‘diets’ (regardless of the rules/restrictions) will cause weight loss – because the total amount you are eating is less than before. The research so far has not found that fasting increases metabolism or improves food choices – so the question is – can you really sustain yourself for a long period of time on this diet (we couldn’t!). Therefore, while it may cause short-term weight loss, as with most diets, in the long term it is unlikely to be an effective weight loss strategy.
What you eat still plays a massive impact as well. If you fast but are living on poor quality food then you may find weight loss does not occur.
Does intermittent fasting have other health benefits?
Most of the research done on intermittent fasting to date has been based on animal studies. While animal studies can shed light on a topic, a rat’s body and a human’s body don’t work the same way and hence we can’t make clear cut conclusions. The small amount of research that has been down (on rodents) has shown some initial benefits of fasting such as improvements in gut health and cholesterol levels. One of the theories behind the benefits of fasting is that the body’s cells adapt to the mild stress of fasting periods and this is thought to enhance resistance to disease. Think of it like exercise – where your muscles are under stress. As long as your body has time to recover, it will grow stronger. There is a similarity between how cells respond to the stress of exercise and intermittent fasting. It’s still unclear whether any of these health benefits are due to the act of fasting or just the overall reduction in kilojoules.
So far no human studies have shown that intermittent fasting reduces weight in the long term, reduces the risk of cancers or prolongs life expectancy, so please don’t use these reasons to jump on the bandwagon.
Potential benefits of intermittent fasting
- Weight loss.
- Contrary to what you may expect, early research shows that people do not over-consume kilojoules on non-fasting days.
- May curb food cravings.
- May help you tune into your hunger signals.
- May reduce inflammation.
- May improve cholesterol levels.
Potential downsides of intermittent fasting
- The quality of your diet may not improve, since you are not educated around what types of foods to eat or not eat (we want to encourage people to choose healthier foods).
- There is limited evidence about the long-term effectiveness or health issues related to intermittent fasting.
- You may experience headaches, fatigue, extreme hunger and low energy levels on fasting days. This may make it difficult to concentrate, perform at your best.
- A smaller total number of meals means there is less opportunity to get essential nutrients in if you do not plan carefully.
- Designated fasting periods may make it difficult to participate in social activities e.g. dining out with friends.
- There is no mention of exercise, and many may find it difficult to exercise on fasting days.
The Biting Truth’s verdict
While intermittent fasting may help you to lose weight in the short term – the long term effectiveness and health benefits are yet to be understood. Personally, we do not like the idea of starving the body. It is important to understand that all diets essentially result in weight loss by ensuring that you eat less kilojoules than you spend – they’re just different means of doing so.
The main thing you need to consider is whether the diet is sustainable in the long term for YOU. Our approach is to adopt healthy eating habits that you can sustain for life and which nourish you rather than restrict you to certain foods. To figure out whether intermittent fasting is your match, see an Accredited Practising Dietitian.
- You might also like to check out review on The Alkaline Diet and Low FODMAP Diet?
- Check out our Flexitarian Cookbook!
- Don’t forget to follow us on Instagram for healthy recipes and nutrition tips.