Break your bad habit: Vegging out every night

“People who are under high levels of stress and who may not have a large network of friends are prone to isolating themselves after work,” says psychologist Dr Leonard Jason. “Eventually, it becomes their default.”

Why it’s bad: People can consume up to 71 per cent more food while they’re glued to the tube, so it’s no surprise that watching more than 19 hours a week increases your odds of being overweight by 97 per cent, according to a Belgian study. And TV is not an ideal way to engage your brain. For every hour beyond 80 minutes that you watch daily, your risk of developing Alzheimer’s increases by 30 per cent, say researchers at Case Western Reserve University in the US.

Break the habit: Decide which shows are must-see, then record them and watch later: zipping through the ads can cut about half-an-hour off every two hours of couch-time. And at least three times a week, make after-work plans that specifically involve being with other people, whether it’s meeting a few friends for dinner, taking a class or joining a recreational sports team.

Make a healthy habit stick

Watch yourself
People who keep track of their goals are better at making their healthy behaviours a habit, found a 2008 study in the International Journal of Obesity. Make a list of the habits you’re trying to establish, then tick off your successes each day.

Time it right
A 2009 study in the Journal of Neuroscience suggests that stress hormones seem to enhance habit-forming systems. Make that work for you by going to the gym after a tough workday – it may help you stick to your fitness routine.

Do it again!
Repeating good habits makes them more automatic. A study published in Personality and Social Psychology Bulletin found that after people chose an option associated with a goal three times (like opting for an apple for dessert instead of ice- cream), they were less tempted by the unhealthy alternative.