By Alex Mlynek  

Since the late 1970s, the number of adult Canadians considered obese has more than doubled to 28 per cent — over 10 million people — according to the Public Health Agency of Canada

Body Mass Index (BMI), where you divide your weight in kilograms by your height in metres squared, is often used to calculate whether someone is obese or not. (Find your BMI here.)

But according to Margaret Ashwell, a nutritional consultant featured in The Passionate Eye documentary, The Truth About Obesity, where fat is located on our body contributes significantly to long-term health risks. 

“We know that your waist-to-height ratio increases when you have more dangerous internal fat,” she says. Fat around the midsection wraps around organs like our heart, liver and pancreas, which raises risk factors for diabetes, heart disease and blood pressure and may reduce life expectancy by up to ten years.

To find out if we have that internal fat she suggests using a string test.

Research shows that 25 per cent of people with a normal BMI score fail the string test. Even though these people are not technically obese, their health could benefit from weight loss.

Some of the latest research explored in The Truth About Obesity reveals that obesity is far more complicated than we once thought — and offers suggestions on what we can do to maintain a healthy weight.

We eat more than we think we do

Behavioural economist Michael Hallsworth says his research shows that we routinely underestimate how much food we eat.

In the U.K. that means that each day, people actually eat up to 30 to 50 per cent more than they believe they have. This is especially true, he notes, of those who are overweight or trying to lose weight. "Eating's often quite an automatic activity, we don't really realize that we've picked up that chocolate bar and we're just grazing on it," says Hallsworth.

That can add up. So, it’s good to be mindful about what we’re consuming by avoiding tempting treats, and we should try to fill up on fruit and vegetables.

Take a pass on fast food

Thomas Burgoine, a researcher at the University of Cambridge, found that England has 58,000 fast food restaurants, a 10 per cent increase over how many there were three years ago.

His research reveals that the more exposure you have to fast food, which contains an estimated 65 per cent more calories than a home cooked meal, the higher your risk of obesity.

“It’s all about convenience and choice, or lack of choice,” he explains. “If we have a lot of food outlets around where we live and where we work and our schools, those outlets become the easy options, and we’re more likely to make those choices because they’re easy, that’s just human nature.”

So forget about the take-out and cook your dinner at home.

Don't exercise to lose weight, but staying active is still key

Many people think that they can justify overeating with exercise, but burning off those extra calories is an almost impossible task. 

In The Truth About Obesity, three subjects work out for a chance to eat their favourite fast food meal.

Steve wanted to eat a whole pizza, containing 1600 calories, but only managed to burn 530 in an intense one-hour workout. "Ridiculous. It is just not worth it," he says, "I would buy mini-pizzas."

And it turns out, working out may not be the best way to burn those calories.

Dylan Thompson, a professor at the University of Bath tracked volunteers as they exercised at the gym one day and as they made small changes to their lifestyle, like walking to work and doing the gardening, the next day to find out which burned the most calories.

Although it varies from person to person, he found that being more active all day can be just as efficient or more than an intense daily workout — and probably more fun.

Eat fibre to feed your gut microbes

Tim Spector, a professor of genetic epidemiology at King’s College in London has tracked sets of twins for decades, and through that research, has been able to study the link between weight and the diversity of microbes in their guts. “There are a hundred trillion microbes in [our lower guts], and they're absolutely crucial in how we process food,” he explains.

Spector says people he’s studied with more diverse microbes in their bellies are skinnier. So, how do you achieve that?

Eat a wide variety of types of fibre from fruits and vegetables, whole grains, and nuts and seeds.

Eat breakfast like a king, dinner like a peasant

Over the last ten years, the average dinner time in the U.K. has shifted to 8 p.m. from 5:30 p.m. New research suggests this may be another reason why we are gaining weight. 

James Brown, an obesity expert found that our bodies have a natural rhythm. "The body is set up to handle those calories much more efficiently during the daytime period than it is at night," he says. A large U.S. study of 50,000 people found that people who ate their main meal earlier in the day had a lower BMI. 

So one simple thing we can do to prevent the pounds from piling on is to eat our bigger meals earlier in the day.

There is no simple solution to keeping the pounds off, say the experts featured in The Truth About Obesity, but taking a series of small steps can be effective.

For the full story, watch The Truth About Obesity.