Intermittent fasting, time-restricted eating are probably terms you’ve heard about, but what is the difference and what does it achieve?

Fasting is simply the act of going for a period of time without food, whether that be 12 hours or a number of days, sometimes even weeks. However, I wouldn’t recommend prolonged fasting without professional supervision.

Intermittent fasting is when you fast on a regular basis, be it daily, weekly, monthly, or yearly. Generally, the more often you fast, the shorter the fasting period. This includes concepts such as 5:2 where for 2 days a week you restrict your intake to 25% of your normal food intake, and one meal a day (OMAD) where you eat only one meal all day and do this once or twice every week.

Time-restricted eating is really a form of intermittent fasting that fits in with your daily natural circadian rhythm. The most popular TRE is 16:8 where you only eat within an 8 hour window every day, and fast for the other 16 hours. The aim is to keep to the same time window every day. Some people find this difficult and need to start slowly with a 10-12 hour eating window where as some seasoned TRE’s reduce down to a 4-6 hour eating window.

So why would you do this…

Weight loss would probably be the biggest reason for most people, and it occurs not just because you are eating less food overall. Fasting also switches the body from using food for energy production, to using energy stored within your body for its energy (i.e. you start burning your own fat stores for energy). It also assists your body to regulate it blood sugar levels, helping reduce insulin resistance. This then maintains something called metabolic flexibility. For this reason, TRE can help prevent type 2 diabetes and has even been shown to reverse it in many cases. For this reason, most people notice that the fat around their belly area really reduces. Who doesn’t want that?

There are of course many ways to lose weight, but people generally find TRE the easiest to follow long term (or for life) and most people enjoy a positive impact on their weight and body shape.

Not eating for a number of hours at a time will of course give your digestive system a good period of rest after it has finished processing your last meal (which generally takes around 5 hours). It has been shown to reduce inflammation, optimise digestive processes and encourage microbial diversity in the gut, one of the biggest contributors to good health.

Studies have shown benefits with TRE for stress, anxiety and depression. Most people find their cognition and memory also improves and foggy brain problems clear.

Once the body has finished processing your last meal, it can switch its focus to detoxification and increasing its antioxidant defence mechanisms. This prevents damage in the body from toxicity and inflammation which in turn helps the body to function better and turn down accelerated ageing, promoting longevity and reducing the risk of chronic and degenerative diseases.

It is tempting to think that “if I’m eating less I can eat what I like”. However, because you are consuming less food, it is important to ensure that what you do eat is high in nutrients. So stick to whole, unprocessed foods such as vegetables, nuts, seeds, legumes, lean meat, eggs, wholegrains and healthy fats such as coconut oil, olive oil and avocado. Because there is a lot of water in food, you will also need to boost your water intake to account for this.

Anything that causes blood sugar to rise and insulin to spike will break your fast. If you feel you can’t go without coffee in the morning, you can still have black coffee, just don’t add the milk or sugar. Electrolyte drinks and vitamin and mineral supplements are fine so long as they don’t contain any calories.