Research clearly shows that cutting calories can slow ageing and increase lifespan. Nutritionist Fiona Workman discusses the best way to start.

Reducing your daily calorie intake by a certain percentage at each meal will improve health, but the prospect of the associated deprivation and discomfort tends to deter all bar the most committed. A less painful option, that is also much easier to follow, is intermittent fasting.

With every meal we eat – even just a snack – we increase oxidation and levels of inflammatory cytokines circulating in the body. Our habit of eating regularly – and humans are the only species to have a regular eating pattern – means we’re constantly in this state, which is concerning given the mounting evidence regarding the role inflammation plays in many chronic diseases.

American cardiologist Mark Houston believes it's critically important for heart health to break this cycle by undergoing an overnight fast of 12 hours, ideally every night, but at least every two or three nights. This simply means finishing dinner by 8 p.m. and eating breakfast after 8 a.m. – or whatever 12-hour period suits your lifestyle. When you consider that for eight of those hours you're probably asleep, it's a protocol that should cause little pain.

Disease prevention

Overnight fasting produces numerous benefits: People have more energy in the morning; insulin resistance improves as it reduces the amount the pancreas needs to release; it reduces leptin; and it helps move fatty acids into cells. These are all beneficial parameters for the two biggest killers: cardiovascular disease and cancer – and virtually every disease we know of. Neurologically, research shows that fasting for a minimum of 12 hours protects neurons against inflammation from the toxic stress of eating, and the metabolic stress of having high blood sugar. So essentially, by preventing degradation of the neurons, fasting can guard against chronic, degenerative, neurological diseases. Many integrative doctors, such as Dr John Hart of the Hart Clinic in Mosman, Sydney, are incorporating the 12-hour overnight fast into their protocols for treating Alzheimer’s disease.

Weight management

Intermittent fasting is also important for weight management, and this is the reason Michael Mosley’s 5:2 Diet became a popular incarnation of the practice. Mosley’s regimen involves eating normally for five days, and on two non-consecutive days reducing calories to one-quarter of the recommended daily intake – around 500 for women and 600 for men.

The whole idea with intermittent fasting is not so much what you eat, but the timing – and restricted eating timing has more benefits than the conventional dieting concept. With intermittent fasting, you can eat whatever you want within a certain timeframe. This melds with the traditional Chinese medicine and Ayurvedic concepts of eating dinner earlier: with Ayurveda, for example, the ideal is to finish eating dinner by 7 p.m. and go to bed at 10 p.m., thereby giving the body three hours to digest the food.

In one trial, researchers studied 400 mice, ranging from normal weight to obese, that were placed on various diets and lengths of time restrictions. Mice that were fed a high-fat diet, but allowed access to food for only 12 hours per day, were healthier and slimmer than mice given access to the same food for the whole day, even though the two groups consumed the same number of calories. The results were the same, even if the diets were high in fat, sugar, or fruit sugars. The study also suggests that the odd blip is unlikely to make a difference. A late-night weekend takeaway, for example, is unlikely to harm the body's metabolism. However regularly eating late at night would have a big impact.

Despite all the positive outcomes, overnight fasting is not for everyone, so consult your natural medicine practitioner first. I suggest to my clients that if they’ve ever missed a meal and not even noticed, it might be something to consider. However, those who find they feel anxious and weak, become a bit snappy-tongued, or experience brain fog when they don’t eat on a regular basis – and this can be as often as every 90 minutes to two hours – may need to be careful about fasting. Pregnant women and diabetics must exercise caution.

Five best methods

With claims that it leads to weight loss, improves metabolic health and extends lifespan, it’s no surprise that there are several different methods of intermittent fasting. Keep in mind, with any of these methods, that (a) calories still count and (b) high-quality food is vital.
*The 16/8 Method, also known as the Leangains protocol. Popularised by Martin Berkham, 16/8 involves fasting every day for 14 to 15 hours for women, 16 hours for men, and eating two or three healthy meals – or more – within an eight-to-10-hour timeframe. Water, tea and coffee can be taken. This method can also incorporate an overnight fast, along with skipping either dinner or breakfast.
*Eat-Stop-Eat, popularised by fitness expert Brad Pilon, is simply fasting for 24 hours – from breakfast, lunch or dinner one day to the same meal the subsequent day – once or twice each week. So, if you finish lunch at 12.30 p.m. on one day, your next meal will be lunch the following day, eaten no earlier than 12.30 p.m.. Water, tea and coffee are permitted. If this method is used for weight loss, it’s essential to eat normally during the eating timeframe. Also, be sure to have normal-sized meals during the eating periods: in other words, don’t load up to compensate for the fast.
*UpDayDownDay™ or Alternate-Day Fasting, created by Dr James Johnson, involves – as the name suggests – fasting every second day. Many lab studies that demonstrate health benefits of intermittent fasting used various forms of this method. You eat normally one day, and the next day you reduce your calorie intake to one-fifth of normal intake, around 400 to 500. This one is not recommended for beginners, and is probably unsustainable for anyone to follow over the long term.
*The Warrior Diet, popularised by fitness expert Ori Hofmekler, focuses on whole, unprocessed foods like those in the Paleo diet, and involves eating small amounts of raw fruits and vegetables during the day, capped by one big meal at night. So essentially you fast all day, and feast at night within a four-hour eating window.
*Spontaneous Meal Skipping simply means skipping meals when it suits you.

Fiona Workman (BHSc DipNut) is a member of the Australian Traditional Medicine Society.