By Brittany Risher

Strangely enough, saying, “I’ll try my best,” can actually suck the motivation right out of you. “This type of vow is vague, making you more likely to procrastinate,” says WH stress-less expert Dr Suzy Green. The result? You put in a whole lot less than your 100 per cent.

Set clear, attainable, challenging goals and give yourself a deadline. “Specific goals help focus your attention and increase your effort, which helps you persist longer,” says Dr Gary Latham, a professor of organisational effectiveness at the University of Toronto, Canada. And because you have a plan of action and a time frame, you’re less likely to put things off.

Another important point: concentrate on three to five big goals at a time. “Any more and your eyes glaze over and you burn out,” says Dr Latham.

READ MORE: The secrets of motivation

We spend three to four hours a day resisting the things we desire, says Dr Roy Baumeister, co-author of Willpower: Rediscovering the Greatest Human Strength (Penguin). That’s why you can turn down that choc-chip muffin in the morning, but have a harder time resisting pizza for dinner. Dr Baumeister says that willpower can be exhausted from overuse; when this happens, your brain either makes impulsive decisions or opts out. “You shy away from complicated decision-making,” he says. “The more often, and recent you’ve resisted desires, the more depleted you are and the more likely you’ll give in.”

Try to take away some temptations – for example, re-route your drive home to bypass your favourite drive-through. Also, clock sufficient sleep, eat well and regularly. “When willpower is low the brain craves glucose, but it’s better to have something that will stabilise blood glucose over a period of time, such as lean protein,” he says.

All that energy and determination you have when you first pinpoint a goal? It’ll fade away if your motivation is off-track. For example: “At the start of a weight-loss program, you’re probably motivated by the desire to be slimmer,” says Dr Kelly Webber, author of a study in the Journal of Nutrition Education and Behavior which found that drive tends to be fuelled by external issues – such as, “my high-school reunion is in two months” – and is much less likely to end in success. What really works is autonomous motivation, when you want to do it for yourself like eating healthier and exercising more, so you feel better and have more energy.

Dr Webber found that women’s motivation levels in the fourth week of a weight-loss plan predicted whether they’d drop kilos and last all 16 weeks of the program. At the four-week point, you know what it takes to be successful – and if you’re still enthusiastic, odds are you’ll keep at it.

To get yourself to that magic point, “Find a friend, family member, or expert who can help problem-solve when you struggle,” says Dr Webber. Easy.