Did you know that Time-Restricted Eating (TRE) can be a helpful strategy for weight loss and that it could also do wonders for your metabolism?
What is time-restricted eating?
Time-Restricted Eating is a type of intermittent fasting that allows a limited time for eating each day. Beginners go for 12:12 (12-hour eating window, followed by a strict fast for 12 hours), most would benefit from 14:10 (14 hours of fasting), and you can extend this for maximum benefit to 16:8.
To be clear, ‘fasting’ means ‘not eating’, and it also means ‘not having anything other than water, herbal tea or black tea or coffee’.
What are the benefits?
- improved weight loss
- reduced inflammation
- better blood sugar control
- reduced risk of diabetes
- enhanced detoxification
- better hormonal appetite control involving leptin and ghrelin
- improved heart health
- slower ageing
- better immunity
- reduced risk of cancer
- improved brain function and reduced risk of dementia
- better stress management
- better digestion
- more diverse gut flora
- faster recovery after exercise
Does it make evolutionary sense?
Humans are not designed for constantly grazing. Until very recently, eating 24/7 wasn’t even possible. For almost all of human history, people had to alternate between times of feasting and times of fasting. Many cultures have been practising intermittent fasting for religious reasons for millennia, and studying subjects who, for example, observed Ramadan – a way of time-restricted (but not calorie-restricted) eating – showed that important health markers, such as blood pressure and cholesterol, improved after a month of intermittent fasting.
How can time-restricted eating help you lose weight?
In the past, the advice was: eat little and often. This was to stop blood sugar from dropping too low. Paired with this advice was the recommendation only to consume slow-releasing, complex carbohydrates, which would ensure that blood sugar wouldn’t rise too high either to avoid insulin spikes. Keeping blood glucose and insulin on an even keel was thought to be the best way to lose weight – and it works, particularly for those who are used to a diet that is high in sugar and refined carbohydrates. After all, small regular meals of healthy foods are already a big improvement for many.
Time-restricted eating means that nothing will spike insulin for 12, 14 or 16 hours, and it is only in the absence of insulin that we can burn fat. Humans are designed to switch between using glucose (carbohydrate) and fat for fuel. We put down body fat as an energy reserve so that when food is scarce, we can live off that for a while. When we eat carbohydrates, insulin is secreted, and one of the things it does is stop fat-burning. If we keep topping up insulin, we will have a harder time losing body fat. Even now, as we sleep, we are burning fat, as the body needs fuel through the night as well. Extending the overnight fast simply allows us to burn some more.
Should everyone restrict their eating time?
TRE may not work for everyone. If you are diabetic or very stressed, it is important to get your blood sugar levels on to an even keel first, and TRE is not recommended. Similarly, if your thyroid is compromised, you may want to be cautious. Unfortunately, there is very little research about intermittent fasting for people with an underactive thyroid. For many, it works a treat, for some, it makes symptoms worse.