Why the Interval Weight Loss diet is the key to staying slim for life
Why the Interval Weight Loss diet is the key to staying slim for life
New research shows alternating one weight-loss month with one maintenance month, is the best way to keep unwanted kilos off for good. This is how.
"I lost 2kg in the first month, then nothing for the next month." If this was an account of someone's weight-loss experience, it would be pretty unremarkable – it may even suggest a lack of commitment or the wrong diet choice to some people. But what if this slow and halting approach, known as interval weight loss, is actually the best way to lose fat and live longer?
That's what Australian obesity expert Nick Fuller is arguing in his new book, Interval Weight Loss. The book's month-on, month-off approach to weight loss was researched and tested by Fuller and his colleagues at The Boden Institute in Sydney over several years.
"We've been wired to believe that dieting is the next best thing, the magic bullet, but it's actually doing the opposite," Fuller argues. Losing a lot of weight quickly puts the body under such stress that it will fight against what you're doing to go back to 'normal', he says. You've got to go slow if you want to outsmart your body.
New research is showing how well this approach works. An Australian study of 51 men compared continuous weight loss with interval weight loss. Not only did interval dieters lose more by the end of the period, but in a six month follow-up, they'd lost on average 8kg more than continuous dieters.
Why you fight to stay fat
Obesity threatens to shorten the lifespan of billions of people around the world – it increases the risk of cardiovascular disease, type 2 diabetes and many types of cancer. With two-thirds of Australian adults (and one in four kids) either overweight or obese, it's "one of the most detrimental health issues of the future", The Royal Australian College of General Practitioners recently announced.
One of the reasons obesity is so prevalent is that it's incredibly difficult to maintain weight loss. For the majority of people who attempt to lose weight through lifestyle measures, within five years that weight has mostly or completely returned.
This is a frustrating statistic, particularly when it's also been shown that losing (and keeping off) a mere 5kg will have a significant improvement on your blood pressure and other health markers – and, as a result, your lifespan.
So why does weight regain happen?
A lack of willpower or discipline is often blamed, but it's actually because your body is used to being the weight it usually is – Fuller calls it a "set point". As a result of rapid dieting, bodies instinctively adjust their metabolism and appetite hormones in order to "bounce back" to this set point, and it's something he's seen time and time again during the decade he's been researching this area.
"Whenever you lose weight or put the body under stress – for example, severe calorie restriction – your body's metabolism will lower, because your body is fighting to get back to where it started," Fuller says.
Dieting also increases appetite hormones, telling you to eat more, but in a cruel twist these often remain elevated even when weight regain has happened – explaining why some people end up weighing more than before they began dieting. "There's been such a great stress on the body, it doesn't properly recover."
But here's the good news: by losing no more than 2kg in a month through eating habits and exercise, your metabolism and levels of appetite hormones will be preserved as much as possible, Fuller says. And by then having a rest month (where the eating and exercise rules are slightly relaxed so your weight stays the same) you are in effect getting your body used to its 'new' set point. You repeat the pattern until you've achieved your weight goal (which a professional can help you to set). From then on, every month is maintenance month.
While interval weight loss is "sensible and realistic," the maintenance month is initially challenging, warns Fuller. "If you see weight continue to come off during the maintenance month, you have to put it back on, and that's a tough concept."
But get your head around it, and you're likely to still keep the weight off in five years' time, which Fuller says is like being "in remission". You can also look forward to a longer, healthier life.
A day's food
Large bowl of porridge with cinnamon, low-fat yoghurt and berries plus milk-based coffee
1 slice wholegrain toast with boiled egg
2-4 wholegrain crackers with salad (mixed leaves, avocado, cherry tomatoes, tinned tuna and olive oil)
Handful of raw nuts and one piece of fruit
Roast lamb (half a palm size) and cup of mixed vegetables
Interval weight-loss rules
You don't need to cut out certain food groups or count calories to lose weight, but these guidelines are key.
During the weight-loss month
* Big brekkie, tiny dinner.
"Eating big to small through the day is the main rule," Fuller says. "It stops a lot of bad eating habits, like grazing when you get home." He recommends eating a bigger breakfast than normal, having a standard lunch, then a dinner portion small enough to fit on a bread plate. Two decent snacks between meals will keep your appetite in check.
* Avoid processed foods.
This is the next most important rule, as these foods are often low in fibre but high in sugar, so they won't keep us full, Fuller says.
* All fruit and veg are OK.
As long as it's fresh (rather than dried fruit), it's on the menu.
Great as snacks, too.
* Lean protein and low-fat dairy.
This keeps saturated fat intake in check. Try to have protein with every main meal.
* Once-a-week foods.
Cheese, a sugary treat and a meal out are all restricted to once a week. A few glasses of alcohol a week is OK, if you can still lose the weight.
* Count the kilos.
A weekly weigh-in is essential, and you'll need to note your weight to make sure you don't lose too much in a month, Fuller says.
* Exercise variety is crucial.
This keeps your lean muscle mass at a healthy level, which helps preserve your metabolism.
Fuller says, try to do something different each time, with at least 30 minutes of moderate exercise five days a week. He suggests using a monitoring device to help rack up 10,000 steps a day.
During the maintenance month
* Same foods, more treats
It could be an extra serve of ice-cream or glass of wine each week, but the idea is to relax your restrictions. It might take a bit of trial and error, Fuller says, but that's OK. The upside is that by the time you've lost your desired weight, you've already got a handle on the maintenance.
* Keep weighing yourself
Stepping on the scales regularly during these months is vital for keeping your weight stable, Fuller says.
* Continue exercising
Regular, varied exercise during maintenance months keeps your metabolism in check. You may need to reduce the amount if your weight continues to fall.
For more information, check out Interval Weight Loss by Nick Fuller (Penguin Random House Australia, $32.99), on sale now.
Psychology of Dieting1:25
Have you tried every diet and exercise trick on the planet and nothing’s worked? Maybe you’ve been missing the secret ingredient: psychology. Next time you consider a weight loss program make sure your brain doesn’t hold you back.