How to lose weight Dr Toni Steer Dr Susan Jebb Take a long, hard look at what you eat and how active you really are, work out what you need to change and use the following principles to adapt your lifestyle.

Cut calories

A gram of fat contains twice as many calories as a gram of carbohydrate or protein. Reduce high-fat foods in your diet, choose lower or fat-reduced options, use cooking oil and spreads sparingly and remove excess fat from meat.

Include lower calorie options in your diet, such as fruit and vegetables. Bulky fibre-rich foods are also a good choice.

Try switching from white to wholemeal bread, or choose a wholegrain breakfast cereal.

Think about portion sizes

Portion sizes have increased over the years, especially when it comes to ready meals and snack foods. This means we're consuming extra calories, but we adapt quickly to eating bigger portions and don't tend to feel fuller as a result.

Downsize potatoes, pasta, rice and fatty and sugary foods, and super size fruit and vegetables.

Watch what you're drinking

Cut sugar-rich drinks and alcohol, and instead choose water, tea, coffee or artificially sweetened drinks.

Sugary drinks add extra calories to your diet but don't make you feel full or satisfied.

Keep a balanced diet

Remember the principles of a balanced diet - include plenty of fruit and vegetables (at least five portions a day), unrefined foods with more fibre, lean meats and low-fat dairy products.

Get active

Becoming more active doesn't necessarily mean sweating it out in a gym. Instead, try the following:

• Choose activities you enjoy and try to spend more time each week on these
• Incorporate more activity into everyday life
• Buy a pedometer and increase the number of steps you take each day

Another good way to become more active is to focus on spending less time sitting down. At home, limit the time you spend watching TV or in front of a computer screen. At work, take regular breaks and if you want to talk to a colleague, walk to their desk instead of sending an email.

Fad diets don't work

Diets that promise quick, effortless weight loss are best avoided. You may lose weight initially, but they're often difficult to follow in the long term. Often they're also very restrictive and may not provide all the nutrients your body needs.

Fad diets are those that:

• Promise a quick, easy fix with rapid weight loss
• Suggest that certain foods 'burn fat'
• Promote the eating of just one of two foods
• Have lots of rules about how to eat
• Sound too good to be true

Yo-yo dieting

Many people who lose weight tend to regain it over time. You can minimise the chance of this by making permanent changes to your lifestyle - by switching to low-calorie drinks and low-fat spreads, for example, or by eating smaller portions. Regular physical activity appears to be especially important in maintaining weight loss.

The following factors are important for maintaining weight loss:

• Small, permanent dietary changes
• Regular physical activity
• Realistic goals
• Regular weighing
• Support from family and friends

Although no one would suggest yo-yo dieting is a good thing, there's little evidence it's harmful to health. However, it's disappointing and can reduce your confidence and motivation.

Recognise that in the period immediately following a diet you're at high risk of weight gain and you need to take specific steps to avoid it.

Remember to weigh yourself regularly. If you notice your weight increasing, take action immediately. Don't let a minor lapse become a major problem.

This article was published in June 2007.