This obesity expert says we have far less control over our weight than we think

For most people, losing weight is a losing battle. The mantra of "eat less and exercise more" does not seem to work.

That is because it is a simplistic formula that does not take into account many other factors that affect our body weight and our health, according to Jennifer Kuk. She is a professor in the department of kinesiology and health science at York University and spoke with Michael Enright, host of The Sunday Edition, about common myths, misunderstandings and misconceptions around weight loss.

These are highlights of their conversation, edited for length and clarity.

Generational differences in weight loss

I'm very fortunate to work with a weight management physician in the local area, and we took all his weight management patients and looked at who is most successful at losing weight, males versus females, older versus younger. When we first started we thought that younger patients would be able to lose more weight. They tend to be healthier and have fewer conditions that might impair their ability to lose weight, and they probably do more exercise. And they're on fewer medications that tend to promote weight gain. So we were a bit surprised that we saw the older individual patients were actually better able to lose what we deem to be a clinically significant amount of weight.

There are many generational factors. One of them would be your ability to cook and grocery shop. Older individuals are more likely to be able to cook from raw ingredients, as opposed to from a box that's prepared that you just preheat. That allows you to control the fat content, the salt content, the sugar content of your food much better, and then you're more aware of what you're actually consuming. One of the things that we see is that music or being elite in sports or getting good grades is more emphasized than having life skills.

Social factors that affect our ability to shed pounds

There's more stress. When you take a look at our permanently plugged-in environment, you never get a break from work. You're always plugged in. Kids are the same way, in the sense that they're always communicating with their friends. They have to constantly update their Facebook or whatever it is or they lose their social standing. All of that stress also influences your ability to control your appetite, to make those good choices and also manage your body weight. Long-term stress will tell your body that you need to conserve. Your resting metabolic rate will actually go down and your fat stores will actually go up in response to chronic stress.

Social networks have also been linked with your likelihood of gaining weight. The more people that are within your close social network who have obesity or are gaining weight, the more likely you are also going to gain weight.

The more people that are within your close social network who have obesity or are gaining weight, the more likely you are also going to gain weight.- Jennifer Kuk

Individuals who are close eat together, they engage in the same type of activities, they have the same type of stressors in their life … so many of the things that are been shown to contribute to weight gain might just be affecting both parties.

If there are environmental pollutants or pesticide exposures that we have in our food sources, they are also going to influence it as well. The areas where we live will influence our walkability, our perception of access to physical activity options, that sort of thing.

The growing effect of the medications we take

When you take a look at the number of medications that the population is on, it's increased astronomically. And when you look at the number of medications that say weight gain is a side effect, it's not a trivial amount. Even if it was only five pounds or a couple pounds, when you add up all of those medications across an entire population, I think that a large proportion of the weight gain is due to the fact that we have medications that promote weight gain.

When you look at the number of medications that say weight gain is a side effect, it's not a trivial amount.- Jennifer Kuk

Why your body weight is more like the stock market, not a savings account

If you think of your body weight as a savings account, what you deposit minus what you take out is your balance. But what we're learning is that your physiology is not like a savings account, it's more like the stock market or your RRSPs. And so there are instances where you can put in money and you have a great year and you gain lots of money or you have years where you lose lots of money. It's the same thing with your physiology. You can eat less and sometimes your body will compensate and burn fewer calories. You can have your physiology flux between something like a monster truck to a Prius.

The effects of exercise on weight loss

There is a large British study that's quite famous that essentially shows the more exercise you do, the more you eat. And once you get beyond this sedentary level, usually your intake matches your energy expenditure. So you have this nice equilibrium. Unfortunately, because we've engineered physical activity out of our lives, there's many things that we no longer have to do manually – simple things like cars, not having to roll down your windows, remote controls on our TVs – so even sedentary activities are more sedentary now. And so we're all within this very sedentary state, which causes a disregulation between our energy intake and our appetite, which makes us eat more or feel hungrier because we're sedentary.

Why we gain more weight in the winter

People do gain more weight in the wintertime. One fantastic way to increase your appetite is through cold exposure. If you sit outside for a while in the cold and you come in, the first thing you think of is, "I'm starving." So the body reacts to that cold exposure by saying, "I need to deposit fat stores." So that actually triggers your hunger hormones.

The biggest myth about weight loss

I think the largest is that if you eat less and move more you can lose all the weight that you want. The people who are able to do that are equivalent to people who have won the lottery. I think that we all know that there are people that win the lottery but not everybody does. And the people who win the lottery and are able to lose weight through diet and exercise are screaming at everybody else saying, "Why can't you do it? I did it." But it would be the same as the lottery winner saying, "I won the lottery. Why didn't you win the lottery?" We see the absurdity of that, but we don't see it when it comes to weight loss.

The best way to lose weight?

I think that probably the best way is to pick the right parents. If you have the right genetic makeup, it defends against weight gain. There's a study that had many people eat a thousand calories extra, which is about a third more than what they normally ate, and there are some individuals in that study who gained nothing, despite not exercising more.

Countering the social stigma around weight

Obesity has been now termed a chronic condition disease by the World Health Organization, so it's important to recognize that they are people first and not a disease. So we don't say "obese people," we say "people with obesity;" just as we wouldn't say, "a cancerous person," we'd say, "this is a patient with lung cancer" or "a patient with heart disease."

You should not equate weight with health. They're not the same thing.- Jennifer Kuk

I don't know if weight loss should be the ultimate goal. I think that the question is wrong. So the right question is, "How do you get healthier?" You should not equate weight with health. They're not the same thing.

You can lose a very small amount of weight and get significant health benefits, but when people look at you you're still going to have obesity. They're still going to think you need to lose another five, 10 or 50 pounds, but that's not reality. So in order for you to improve your health, the amount of weight that you need to lose is very small. Most people with obesity, if they lost five per cent, they would get healthier, they'd feel better they'd have more energy, but they would still be classified as having obesity. And people would look at them and still say you know if you lost a few pounds you'd be healthier. Bariatric surgery is the best obesity treatment that we have, and most patients after bariatric surgery still have obesity.

Click 'listen' above to hear the full interview.