When it comes to keeping fit, a positive mental attitude can be your biggest ally. Your body can always persuade you that having another slice of cake or a long lie-in is a great idea, but your rational brain knows that your best chance of living a long, happy and healthy life is a fit body, and this means making a balanced diet and regular exercise your everyday priorities.

With the dull days of winter dragging on, it is easy to lose sight of those vague "good resolutions" you made in the New Year. However, with spring just around the corner, now is an ideal time to revisit them and devise a realistic fitness plan and exercise regime. Here are a few tips on how psychology can help you stick to it.

• Persistence

A study conducted by psychologists at the University of Hertfordshire showed that people with “fatalistic attitudes” were the least likely to adhere to their resolutions. So, if after a few days of embarking on your healthy eating plan, you raid the biscuit tin and think, “That is it; I have got no willpower – I give up!” you will never succeed. Just start again the next day and be persistent – just try, try again, and don’t make the odd slip-up an excuse to abandon your goals.

• Fool Your Brain

According to the Small Plate Movement (yes, apparently it does exist) you can lose weight just by swapping your 12” dinner plate for a 10” one. Thanks to a powerful optical illusion called the Delboeuf effect, the same portion of food looks smaller on a big plate and bigger on a small one, so you are fooled into eating less at every meal. Furthermore, it appears that you eat 30% more pasta in a tomato sauce served on a red plate, than if it’s served on a white plate, as the food blends into the plate and the serving looks smaller. So get out the small white plates on pasta all’Arrabiata night!

• Support

Tell your friends and family that you’re trying to lose weight/give up smoking/get more active, and enlist their support. Explain that you’re just trying to keep healthy and live well. If they really value you, they will encourage you and, hopefully, join you at the gym and improve their own health and fitness too.

• Make Your Goals Achievable

If you’ve never exercised before, deciding that you’re going to win the London Marathon may be an unrealistic goal, and just thinking, “I’ll get fit” is too vague. It may be better to start by committing to going to the gym once a week and fitting in a swim or a run on other days and build up from there, until you are doing some exercise every day. Be realistic – you’re more likely to succeed if you focus on one goal, rather than having a whole raft of aspirations.

• Write Things Down

Make a checklist of how your life will improve once your fitness goals are achieved and give yourself small rewards to keep up your motivation. It’s helpful to keep a written record of your gym visits, participation in sport or other active pursuits; this could be something public like a blog or just a private spreadsheet or journal. If you book exercise activities into your diary or timetable, as if they were work commitments, you are more likely to stick to them.

• Understand What Triggers Your Bad Habits

If stress triggers you into reaching for a chocolate bar or cigarette, just don’t keep those unhealthy things in the house. Instead, try a yoga class to relax you or a dance class to release those happy hormones and combat anxiety. It is possible to create new triggers to prompt you into healthier habits. For example, when the news starts, you could make that the time when you head for the gym.

So, if you follow these tips and use “mind over matter” to overcome pitfalls and disappointments, you are more likely to stick to your goals and achieve beneficial and long-term improvements to your health and fitness.