Fasting is the latest nutrition buzzword, but if you’re anything like us and you love eating, then you probably need a damn good reason to go for any length of time without food. Well, how does a longer life sound? What about reduced cancer risk? If that doesn’t do it for you, we’ll throw in improved body composition and blood cholesterol, all without calorie restriction. Sounds too good to be true, right? We get the lowdown on this hot topic from intermittent fasting (IF) expert and nutritionist Martin MacDonald.
What is intermittent fasting?
Flipping the grazing theory on its head, intermittent fasting involves fasting for either a day at a time or allocating a set window in the day when you eat all your meals, such as 1 p.m. to 9 p.m. Eating in this way is thought to aid weight loss and boost overall health, and it removes the need for calorie control. There are several types of fasting, so you can choose one that suits your lifestyle.
Why do it?
A longer life is a huge promise, and, after having been told to keep your metabolism firing on five to six small meals a day, we wouldn’t be surprised if you were a little skeptical. So how does IF work to help you live longer and slim down? One human study published in the American Journal of Clinical Nutrition found that after fasting, people didn’t eat as much as they would normally, creating a calorie deficit. “Perhaps one of the overriding factors as to why IF has been so successful is that it improves adherence to a good eating plan,” explains Martin. “Now we’re no longer scared of slowing our metabolism by skipping meals if there are no ideal choices around at the time.” This is great news if eating little and often has left you unsatisfied and inconvenienced.
“On an IF program the meals are larger—satisfying—and you can have healthy carb-filled dinners and still lose fat,” adds Martin.
IF has positive effects on growth hormone levels and insulin sensitivity, too. During extended fasting periods, growth hormone increases—a hormone that is key to building lean muscle and burning fat. “Exercising in a fasted state may also have some unique benefits that increase insulin sensitivity,” Martin adds. Try to arrange your “feed” so that it follows a gym session for best results.
The other bonus of IF is its effect on a hormone called insulin-like growth factor 1 (IGF-1). While we need this hormone earlier in life to grow, later in life it seems to speed up the aging process, and low levels of IGF-1 appear to protect people against cancer. “In times of fasting, IGF-1 goes down,” Martin explains. “It may be that IF allows for a ‘best of both worlds’ scenario, where the aging process is slowed without having to sacrifice vitality, body composition and bone health.”
Make IF work for you
If you think IF sounds too extreme for the average Joe, consider this: with a busy lifestyle, how likely are you to stick to the six-meals-a-day mantra without having to make occasional poor food choices due to inconvenience?
“Regular people with regular jobs are probably the most likely to benefit from IF,” says Martin. “Some hunger is natural; your body is not going to go into starvation mode. Just don’t eat when you don’t have access to good food.”
With IF, you don’t have to follow a specific diet, which means you can enjoy the foods you like to eat and forget about regimented plans.
“When intermittent fasting, it’s important to pick foods that allow you to hit your protein intake,” Martin adds. “This is easier than you think. If you switch from regular yogurt to Greek yogurt for instance, you’ll get double the protein in one serving. A variety of carbohydrates and good fats are also required to supply you with energy.”
Who shouldn’t do it?
IF isn’t for everyone. Don’t try it if you’re pregnant or a type 1 diabetic. “Type 1 diabetics using insulin can have hypoglycaemic episodes if they go for long periods without food,” Martin says.
Choose your plan
Find a fasting method that best suits your lifestyle. Here are a few of the options:
Alternate-day fasting
This is pretty straightforward: fast for an entire day, and the following day, eat whatever you like.
“The benefit here is that you’re only ‘dieting’ 50 per cent of the time, albeit with absolutely no food,” explains Martin. “We usually see body fat lost with this method, but going without food for an entire day is difficult, and it doesn’t allow for exercise on fasting days.”
Windowed eating
With this type of fast, you eat within a certain window of the day only. “This may be the best type for individuals who exercise regularly,” says Martin. “It limits the amount of time you can eat each day, and depending on which type you do, this could be anywhere between two to eight hours, which generally fits around exercise and occurs later in the day for social and sleep benefits.” You’ll need to consume all calories within your feeding window in one to four meals.
Extended nighttime fast
“This type of fast essentially means skipping breakfast or dinner to extend the time without food during sleep,” says Martin. “It’s similar to windowed eating but it’s more flexible.”
5:2 fasting
It’s not strictly fasting; it’s more about restricting calories for two days a week. A less dramatic version of IF, it means setting aside two non-consecutive days where you eat no more than 600 calories. “It can lead to an improvement in a number of health markers,” says Martin. “Prolonged periods without food increase the body’s sensitivity to hormones like insulin, which reverses insulin resistance, the first stage of type 2 diabetes.”•
