Many religions practice periods of fasting and our hunter-gatherer ancestors would certainly have gone for long stretches without food so fasting is nothing new. Intermittent fasting (IF) is now being hailed by many nutrition experts as an important anti-aging and health promoting style of eating that many of us would do well to adopt.
There are several ways to fast and my favourite (and definitely the easiest method) is to go for 14-16 hours without eating – for me this means finishing eating by 8.00pm and not eating breakfast until 10.00am the next day. I don’t manage this every day but always fast overnight for at least 12 hours. The total number of calories eaten in a day does not need to change, it simply means eating within a more restricted time frame. Many of us do this naturally at weekends waking late to enjoy a brunch so we know how easy it is.
Dr Kiran Krishnan, a renowned microbiologist, advocates finishing dinner at 8.00pm and then eating again from 12.00 midday the following day, allowing himself 8 hours a day for eating. Similarly a nutritionist colleague of mine finishes eating by 5.00pm and enjoys breakfast the next day at 9.00am. giving herself 8 hours a day to eat.
More hardy intermittent fasters might have a 24 hour fast once or twice a week, typically eating a good breakfast and lunch and then not eating again until lunchtime the next day.
Nutrition is an evolving science and advice tends to change as new research makes advances. I studied nutrition in the early 90’s when we were taught that eating small amounts regularly was the best way to keep blood sugar balanced and for many years I told all my clients to do this but I now believe this to beoutdated advice and that we really need to have a fresh look at when we eat as well as what we eat. Research means that we now understand a lot more about insulin resistance and type 2 diabetes, we have a lot more knowledge about the microbiome (bacteria within our gut), about inflammation, oxidation and heart disease - all of which have been shown to benefit from IF.
Before you embrace IF a word of warning – do not attempt any form of fasting if you are hypoglycaemic or diabetic (not for pregnant or breast feeding women either). It is very likely that you have blood sugar problems if after a few hours without food you feel weak, light-headed or irritable. If you suffer from blood sugar problems you should see a qualified nutritionist and sort this out first.
5 reasons to start IF
1. Prevents Insulin Resistance
IF reduces circulating glucose, reducing insulin levels in the blood and in turn helping to normalise insulin sensitivity – all of which means a reduction in insulin resistance. Improved blood sugar balance results in fewer cravings for sugar and stodge so the knock on effect is that many people who start IF lose weight. Insulin resistance contributes to most chronic disease - diabetes, cancer and heart disease - so improving insulin sensitivity is a must for improving health.
A study in the British Journal of Diabetes and Vascular Disease 2013 found that
“ individuals with type 2 diabetes who fast on consecutive or alternate days not only lost more weight but also acquired cardio protective benefits and experienced better hearth health’
2. Improves Cardiovascular Health
IF has been shown to lower blood pressure as well as blood levels of LDL cholesterol and fat and is therefore a helpful tool for improving cardiovascular health.
3. Boosts Human Growth Hormone (HGH)
IF is thought to raise levels of HGH which results in improved muscle mass and better bone health slowing the aging process.
4. Reduces Inflammation
IF has been shown to result in reduced inflammation in the body. IF decreases oxidative stress warding off cell damage and thereby preventing cell death and increasing longevity.
5. Boosts the Health of the Microbiome
Certain beneficial bacteria inhabiting the gut thrive in a fasted state so IF helps to increase the numbers of these bacteria. Diversity of the gut bacteria is key to good gut health and improved immunity.
Eat well during your eating hours including lean protein and healthy fats and reducing sugar and refined carbohydrates to a minimum.
My advice is also try exercising first thing in the morning in the fasted state whilst your body is still in the fat burning phase. Break your fast with a meal rich in protein and good fats (eg. eggs, salmon and avocado) to reduce insulin release.
You can work IF into your life gradually starting with an overnight 12 hour fast and gradually building to 14-16 hours. Try it for yourself you may be amazed by how good IF makes you feel!