Another big night out, another kebab - suddenly your jeans are too tight, you're puffed out walking up the stairs and, before you realise it, you're overweight. But it's not just your jeans that are feeling the pressure. Your heart, breathing, blood pressure and joints are all affected by carrying excess weight. If you're concerned, talk to your doctor (GP). They're likely to check your Body Mass Index (BMI), which will give you an idea of how much weight you need to lose. Use the interactive tool below to calculate your BMI...

Losing weight

Diets aren't the way to go. They create temporary eating patterns and, therefore, temporary results. The only real solution to shedding the pounds permanently is to do it gradually and sensibly. According to WeightWatchers, losing one to two pounds per week is considered healthy. To achieve this, you need to burn more calories than you consume by eating less, moving more, or - best of all - a combination of both.

Balanced diet

Take a long look at your diet. Do you really need that 'grab bag' of crisps every morning? Munching your way through high-fat snacks is often borne out of habit. Break this and you'd be surprised at the difference. You can put on 5lbs a year just by eating one extra biscuit a week. Ditch it and you'll lose the same amount.

Keep a food diary for a week and see where you can cut back; discussing it with a dietician can help. There are ways to reduce your calorie intake without having to alter your diet significantly, try:

• Replacing foods that are high in saturated fat with those that are low in fat, such as fruit, vegetables, unrefined carbohydrates (whole grains and potatoes) and lower-fat dairy products
• Swapping fizzy drinks for water and cordial
• Not having sugar in your tea and coffee and switching to skimmed milk
• Eating at least five portions of fruit and vegetables a day
• Not to skip breakfast

Start cooking at home and grill, poach, steam or boil food instead of frying. Choose lean meat, fish, eggs and alternatives, such as beans and lentils, use low fat oils and reduced fat mayonnaise. Healthy doesn't have to mean tasteless. Experiment and try using low-fat ingredients in classic dishes, such as turkey meat in your spaghetti bolognaise, or reduced fat cheese in your macaroni. Just remember to keep an eye on your portions.

Making simple changes can mean permanent results, but you don't have to give up everything you love. "Healthy eating is all about balance, so there's no reason to totally cut out fatty foods," says Dr Elisabeth Weichselbaum, Nutrition Scientist at the British Nutrition Foundation. "You can still have a kebab, but go for a shish instead of a döner, which has fewer calories."

Get fit

Be realistic about your expectations. If scoffing Creme Eggs on the sofa is your idea of heaven you're not going to relish the idea of pounding a treadmill. When it comes to improving your activity level, start small and adopt a new mantra 'anything's better than nothing'. Begin by incorporating more activity into your daily life, for example, start walking up the stairs instead of using the lift, get off the bus early and walk the extra distance, dance, skip and do lunges and squats around the house, have more sex - anything that gets your heart racing and your blood pumping.

You can even get fit playing computer games. A study by Liverpool John Moores University found regular use of a Wii console could help shift 27lb (12.25kg) a year. "An average person, say 60kgs, can burn 200-240 calories in a one-hour session," says Professor Stratton, Professor of Paediatric Exercise Science.

Try and build up to 20-30 minutes of physical activity a day and you'll notice the difference.

Don't give up

There will be times when your willpower could be in serious trouble. Alcohol stimulates appetite and that can make a bag of chips on the way home very hard to resist. To reduce temptation, eat before you go out. Drink sensibly - remember alcohol's loaded with calories - and try not to exceed your daily limits. Better still, have alcohol-free nights, but don't be tempted to binge drink just because you've had a night off. 

However, if you really can't resist a take-away there are still ways to indulge without the guilt. "Rather than choosing curries based on coconut milk, go for a dry curry, which is much healthier," says Dr Weichselbaum.

Benefits of losing weight

Studies have shown that, when overweight, losing (and keeping off) 5-10% of your body weight can significantly reduce your risk of: heart disease, stroke, diabetes and some cancers. It may take a week or two before you notice any physical changes, but they will appear. Soon you'll feel more energised and sleep better. Your clothes will fit well; your skin will improve and best of all so does your mood.

Updated: 23/02/2011

Nicola Scott