Does fasting actually help you lose weight?

Publish Date
Saturday, 11 November 2017, 12:52PM
Photo / Getty

Photo / Getty

I'm not the kind of person who can go 16 hours without eating. I adore food the way others adore fluffy kittens and the smell of new babies. If I'm not eating, buying or preparing food, I'm thinking about what I'm going to eat, buy or prepare.

The problem is that when you're a smidgen over 1.5m tall, all that eating means the love handles can get a little too much love. I need to find a way to rein in the consumption.

Dieting is out: over the years I've cycled through every conceivable food restriction programme and most of them left me bored, feeling deprived and with little movement of the scale. I'm done with counting calories, horrendous green juices that taste like grass-clippings and the tedious inconvenience and guilt of it all.

What I need is a lifestyle change, something I can tuck into my routine that I don't have to starve myself stupid for, that's socially appropriate (I still want to be able to enjoy a meal out) and easy to follow. If there are associated health benefits, other than weight loss, well that's the icing on the low-fat cake as far as I'm concerned.

One evening over a carb-heavy platter and too many bottles of wine, my friend Jo suggests I try intermittent fasting (IF). This busy mother and nurse hasn't eaten breakfast for five years, having her last meal before 8pm and not eating again until noon. She credits IF with helping her lose 13kg, as well as a host of other benefits from improved mood, memory and learning function to lower blood pressure and a longer life expectancy.

She had me at 13kg. My only issue is with the word fasting, which conjures up images of politically motivated hunger strikes and gimmicky diets. (Anyone remember the maple syrup and cayenne pepper regime?) Not to mention religious events such as Ramadan and Lent.

But Jo reminds me that fasting has been around ever since our loin cloth-wearing, spear-chucking ancestors roamed the planet in search of food. "From an evolutionary perspective, three meals a day and constant snacking is a modern invention," she says. "Our ancient ancestors ate whenever food was available, which meant long periods of fasting. Our bodies, therefore, are designed to survive in times of feast and famine. Going without food for a few hours, or even a day or two, is possible."

It's not about starving yourself, which can cause the body to hold on to stored fat instead of burning it off as fuel, she says. Instead, IF, also known as scheduled eating, typically refers to eating only during certain periods of the day.

Sounds good, but what do the experts think? Dr Mark Mattson, neuroscientist at the US Institute of Aging and Professor of Neuroscience at John Hopkins University, concurs. "The body converts food into glycogen - a form of energy that it can store for later use," he is reported as saying. "Your body then squirrels that glycogen away in both fat cells and in your liver. If you're eating all day, the stores of glycogen in your liver are never depleted."

On the other hand, after about 12 hours without food, your liver runs out of glycogen - at which point the body starts drawing energy from the glycogen stored in your fat cells. Cue fat burning mode and a whole heap of other reported health benefits.

There are, apparently, three ways to do IF: the 5:2 diet, in which you eat regularly for five days a week and restrict your intake to 600 calories during the next two; alternate day fasting, where you rotate between standard and 600-calorie days, and time restricted eating, in which eating is limited to an eight-hour period each day.

I settle on the latter - being able to sleep through the hardest part of the fast sounds good to me. Which means no food after 8pm, nor before noon the next day. I worry that the eight-hour window will be one long binge fest but Jo and the internet tell me otherwise.

"It's odd but you won't over-eat," says Jo. "When you're only having a couple of meals a day, you choose your food more carefully and I found I was eating better. I never once felt like cramming in as much food as possible into the eight hours."

A study from the University of Southern California backs her up, finding that, contrary to popular belief, people did not consume more kilojoules during the non-fasting window.

I'm sold. I decide I will fast for three weeks, eating dinner before 8pm and not eating until lunchtime the next day, with a snack around 3pm.

It's not, of course, as easy as it sounds and the first few days are tough. Every morning, I drink my usual bucket of green tea and don't feel hungry until around 10am, when a pounding headache develops behind my right eye. I'm not used to this gnawing sensation in my stomach but I feel oddly "lighter", which results in a blast of energy and alertness (Yale University researchers found that working on an empty stomach actually helps you think and focus better). This could explain why, headache notwithstanding, I power through my morning's tasks. Fortunately, because I work mostly from home, I'm not distracted by others' eating habits.

Around 11am each day, when my stomach siren goes off, I do what a nutritionist once advised - add a teaspoon of cinnamon to a cup of hot water. Not only does it make me feel full, it also satisfies my cravings for something sweet.

Strangely, when midday rolls around, I don't latch on to the fridge as though it's the last helicopter out of Saigon. I have my usual lunch, some fruit at 3pm and dinner at 6.30pm. My frequent trips to the pantry to shove everything from chocolate sprinkles to handfuls of muesli into my gob also cease. It doesn't take long, but eating becomes an experience to be enjoyed rather than a boredom-filler. I'm at a loss to explain it, but somehow I felt fuller with less food.

Within a few days, bypassing breakfast becomes the new normal and, thankfully, the hangry switches off. There is a minor hiccup in week three when I have a work brunch and a two-day trip out of town, which makes it too hard to maintain the IF, but I simply slide back into it the following day, amazed at how easy it is - there's no counting calories or banned foods, you simply don't put anything in your mouth except water and tea/coffee for 12 hours.

The real pay-off comes at the end of the three weeks, when the scales show I've dropped 2kg. And that's with no change to my usual exercise routine of daily dog walks, a couple of runs a week and a yoga class (when I can be bothered). Even better, it's my pesky belly fat that seems to go first.

Will I stick with it? You bet. I'm not nearly as hungry as I once was and reckon I could go a whole day without eating and not notice. My energy, focus and motivation have all skyrocketed and it has also saved me time and money, having to buy and prepare one less meal as well as late-night snacks.

My husband, of course, thinks I'm nuts; he's a committed member of Team Breakfast is the Most Important Meal of the Day, and tries to taunt me at the weekend with stacks of fat, fluffy pancakes. But it's been almost five weeks since I gave breakfast the heave-ho and I have no intention of going back.


• Short-term fasting has been found to increase "neural autophagy", which is how cells regenerate, repair themselves and recycle waste. Basically, more of this equals a boost in memory as well as brain and learning functions.

• Studies on rodents at the US National Institute of Aging have shown that during the fasting period, cells are put under minor stress, to which they react by enhancing their ability to cope with stress. This could help resistance to diseases such as Parkinson's, Alzheimer's, heart disease, cancer, asthma, epileptic seizures, diabetes and strokes.

• The University of Illinois studied the effects of alternate-day fasting on hundreds of obese adults and an 8-10 week trial found participants, on average, lost about 5.8kg and experienced marked reductions in cholesterol, blood pressure and insulin, the fat-storage hormone.

• IF practitioners have also reported increased energy, better digestion and sleep and improvements to mood and motivation.

NZ Herald.