It is the rare person who has enough raw willpower to reach their goal unwaveringly. Most of us stumble time and again... but why?

Scientific research provides some answers that can help us stick to that diet, curb spending, exercise more, or stop smoking.

One thing at a time

Scientists know that tackling your bad habits all at once is no way to kick them.

Evidence shows that self-control is a limited resource, useful only in the short term. Like a muscle, it weakens with use. So it’s difficult to deny yourself dessert after eating a low-fat dinner. And it may feel excruciatingly hard to stay away from a post-meal cigarette.

So, first and foremost, take it one thing at a time.

Like it or not

“There is a set of basic fallacies that we all fall for,” explains Janet Polivy, a University of Toronto at Mississauga behavioural psychologist. “The promise that the outcome is going to be fast, so we won’t suffer long. That it’s going to be easy, so we won’t suffer very much. And that it’s going to be super rewarding.”

The harsh reality is that changing an engrained behaviour is none of these things, she warns. And the fact that we enjoy our bad behaviour so much sets us up for failure.

“One thing that’s fairly obvious,” says Polivy, “is that people don’t take into account that the behaviour they’re trying to change is something they like to do. People want the outcome of change, but they don’t like the process.

“You have to rethink things,” she suggests. “Ask yourself: How can I reach my goal by doing something I do like?”

Do's and don’ts

Don’t waste your money on a gym membership you’ll never use, Polivy counsels. Don’t vow to stop shopping for the whole month of March.  

Instead, “acknowledge up front that you’re not going to do things you don’t like,” she says.

Swearing off all of your favourite fattening foods won’t work. But if you fill up first with fruit or a salad, you’ll find it easier to eat less of your treat. Curb your daily shopping habit by promising to buy yourself one really nice item at week’s end.

“Find ways to increase exercise that are appealing to you,” notes Polivy. “Maybe the gym isn’t pleasant, but golf would be. Carry clubs and walk the course with friends. Make it a social occasion. You don’t even have to swing a club.”