The concept of intermittent fasting stems from our hunter gatherer ancestors who would naturally live in cycles of feast and famine when food was not always readily available.
Fast forward to now, intermittent fasting has gained popularity around the world, so let’s explore what all the hype is about….
What is intermittent fasting?
Intermittent fasting is an eating style rather than a diet, involving the consumption of food within a set defined time period across the day. Unlike a traditional calorie restricting diet, intermittent fasting does not control what you can consume, rather it dictates the times you eat or consume beverages other than water or black tea/coffee.
There are a variety of ways in which intermittent fasting can be implemented. Some of the common variations include:
- 16/8 time restricted eating: 16 hours of fasting with 8 hours of eating in a 24 hour period. Typically fasting and eating at the same times each day. For example, stop eating dinner at 8pm and wait until 12pm the next day before consuming a meal.
- Alternate Day Fasting: 24 hours of fasting followed by 24 hours of normal eating.
- 5:2 diet: On 2 days of the week total energy is limited to 2000-2500kJ per day. The remaining 5 days of the week you should eat normally.
What are the benefits of intermittent fasting?
Intermittent fasting has been widely studied in animals, however in recent years new research has indicated that these advantages may also apply in a similar manner to humans.
These proposed benefits include:
- weight loss
- improved metabolic health
- better sleep
- enhanced cognitive function or concentration
- may reduce LDL (‘bad’) cholesterol, blood triglycerides and inflammatory markers
- may reduce blood pressure
- may increase insulin sensitivity
- may help to protect against type 2 diabetes, cancer and Alzheimer’s disease
- enhanced life expectancy
- convenience associated with less meals to prepare and consume
Disadvantages of intermittent fasting
Despite some of the proposed benefits as outlined above, some people may also experience negative side effects of intermittent fasting. These may include:
- feeling of weakness and hunger
- headaches
- malnutrition
- eating disorders or disordered eating thoughts/behaviours
- dehydration
Take home message
Intermittent fasting is a tool that may or may not provide benefits when it comes to greater weight loss, improved metabolic health or increased lifespan. It’s worth keeping in mind that intermittent fasting is not going to be suitable for everyone and it is recommended that you seek the guidance of an Accredited Practising Dietitian to discuss how (if at all) it should be implemented based on your specific needs and goals.
