The truth about fasting: should you be doing it?

You will know that what you eat is very important for your health and wellbeing, but not eating is just as important. Extended periods of not eating are called ‘intermittent fasting’, and when the body fasts, all kinds of magic happens, from accelerated weight loss (and specifically fat loss) to normalising of your blood sugar levels, cholesterol, and blood pressure. Your body gets the chance to rest and repair in a way that it can never do when you are constantly grazing on food. The cells in your body have time to clear out the old rubbish and regenerate, which is great news for resetting your gut bacteria. Plus, when you choose to fast, you’ll save time and money.

There are many different ways you can fast, some of them easier and more practical than others. You can choose to fast for hours (between dinner and breakfast the next day), alternate days, two days a week or days on end. The fast probably most recommended by nutrition practitioners is Time Restricted Eating (TRE) and it involves, quite literally, restricting the hours in which you eat.

A 12-hour fast means you eat breakfast at 7am and dinner at 7pm balanced by 12 hours fasting overnight. This is how we all used to eat. 3 meals a day with no snacks in between, every day.

Extending the fast to 14 (with an eating window of 10 hours) or – better still – 16 hours (with an eating window of 8 hours) brings increased benefits. That would mean having breakfast at 9am (14-hour fast) or 11am (16-hour fast), then having your last meal at 7pm. A 16-hour fast is sometimes referred to as the ‘lean gains method’. You would do this on a daily (or almost daily) basis, adjusting the time you eat your breakfast (or even skipping breakfast entirely) depending on the timing of the evening meal the night before.

What are the benefits?

The most obvious benefit of fasting is weight loss, but there are many other positive benefits reported by those who fast regularly. These include:

·       lower levels of inflammation

·       better blood sugar control

·       lower risk for diabetes

·       enhanced detoxification

·       better hormonal appetite control involving leptin and ghrelin

·       improved heart health

·       slower aging

·       better immunity

·       lower risk of cancer

·       improved brain function and lower risk of dementia

·       better stress management

·       better digestion

·       more diverse gut flora

·       faster recovery after exercise

Does it make evolutionary sense?

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.

I firmly believe that constant eating, snacking and grazing is a major contributor to the high rates of obesity, type 2 diabetes and poor metabolic health that we see today. We need to give our digestive systems and bodies time to rest and repair!

Can time-restricted eating help you lose weight?

In the past the advice was: Eat little and often. This was in order to stop blood sugar from dropping too low. Paired with this advice was the recommendation to only consume slow-releasing, complex carbohydrates, which would ensure that blood sugar wouldn’t rise too high either in order 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 for 12, 14 or 16 hours nothing will spike insulin 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, this is known as ‘metabolic switching’. 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.

What about longer fasts?

There are other longer types of fasting including the 20- or 24-hour fasts and alternate day fasting for 36 hours. Some people choose to go on a medical fast for 5 or even 7 days. This is called ‘periodic fasting’ and is something you might try every few months but only under the guidance of a nutrition practitioner.

Who shouldn’t fast?

Fasting 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 time-restricted eating is not recommended. Start off with just two non-consecutive days per week to see how you get on.

Women also need to fast differently at different times of their menstrual cycle. This is to support hormone production, as women are more insulin sensitive and insulin resistant at different times in their cycle.

If you have thyroid issues, speak to your nutrition practitioner before trying fasting. Also, some people with digestive symptoms may fare better on smaller, more frequent meals and should seek professional guidance before attempting a fasting programme. Fasting also isn’t appropriate for children, pregnant or breastfeeding women, anyone very underweight (BMI less than 18) or recovering from eating disorders.

Getting started with fasting

The first job is to choose the kind of fast you are going to do and stick to it. If you know you’ve been eating a diet that’s not great, you’re a big snacker or you eat late at night, starting with a 12-hour fast is what you need at first. Do this every day for a week, eating three meals a day and no snacks. As this starts to feel manageable (or if you are already pretty much eating to this kind of pattern), stretch your fast to 14 hours or 16 hours, again eating meals but no snacks in between.

However you want to fast, the ideal scenario is that you work alongside a nutrition professional who will be able to tailor a programme for you to tackle any health goals you have and feed and nurture your body with the right foods during your ‘eating window’, for maximum health benefits.

I can advise you on:

·       How to fast effectively

·       What to drink whilst fasting

·       Possible side-effects and how to manage them

·       What to eat when you break your fast and why it matters!

Get in touch or book a call with me if you want to find out more.