To maintain good health, we need to eat a variety of foods from the five food groups. Eating them in the right proportion will help to keep your weight under control.

A sensible rate of weight loss is around 0.5kg to 1kg (1lb to 2lb) a week. To achieve this, you need an energy deficit of 3,500kcal to 7,000kcal a week, which means eating 500 to 1,000 fewer calories a day.

You can do this by replacing high-fat foods with those that are low in fat such as fruit, vegetables, unrefined carbohydrates and lower-fat dairy products, and by being more physically active.

It’s also important to watch the size of your portions. This can be difficult, because over time you can lose touch with what’s a sensible amount of food.

Meat, fish and alternatives

Meat, fish, eggs and alternatives, such as beans and lentils, provide protein, which is essential for growth and repair. These protein-rich foods, meat in particular, are also good sources of iron, selenium, zinc and B vitamins.

Lean sources of protein can also help to curb your appetite. To help reduce the calories you get from fat, remove the skin from chicken, cut off obvious bits of fat from lamb, pork and beef, and use minimum oil for cooking.

Aim to eat two portions of fish a week, one of which should be oily fish rich in omega-3 fatty acids, such as salmon, sardines or trout.

You should have two portions of protein-rich foods every day. A portion is equivalent to:

• Meat and fish the size of a pack of playing cards
• Two eggs
• Four tablespoons of lentils or beans

Bread, cereals and potatoes

Starchy carbohydrate foods, such as bread, potatoes, rice and breakfast cereals, provide us with energy and other nutrients, including iron and B vitamins.

Starchy foods should make up about a third of your total daily energy intake.

Choose unrefined types that are higher in fibre. They’ll make you feel full for longer and help to control hunger.

A balanced diet should contain about five portions of starchy foods each day. A portion is equivalent to:

• Three tablespoons of breakfast cereal
• One large slice of bread
• One chapatti
• Three heaped tablespoons of pasta
• Two egg-size potatoes
• Two heaped tablespoons of rice

Fruit and vegetables

Fruit and vegetables provide essential nutrients such as vitamins and minerals, and contain many other compounds associated with good health.

Everyone should aim to increase the amount of fruit and vegetables in their diet.

Because fruit and vegetables are bulky and contain a lot of water, they can help to control your calorie intake. Aim for at least five portions a day.

A portion weighs about 80g and can include fresh, canned, frozen and dried fruit and vegetables. A portion is equivalent to:

• Two large tablespoons of vegetables, such as peas, carrots, swede or broccoli
• Whole fruits, such as one apple, one orange, one pear
• A handful of grapes
• Two tablespoons of strawberries or raspberries
• One small glass of fruit juice
• A handful of dried fruit

Milk and dairy foods

Foods such as cheese, yoghurt and fromage frais are an important source of calcium as well as providing protein and vitamins. Choose low-fat or reduced-fat versions to reduce the amount of calories in your diet.

Aim for around three portions of dairy foods a day. A portion is equivalent to:

• A medium-size glass of milk
• A small pot of yoghurt
• A small matchbox-sized piece of cheese

Foods containing fat and/or sugar

Fatty and sugary foods, such as crisps, spreads, oils, creamy dressings, sweets, cakes, biscuits and chocolate, and sugar-rich drinks, including alcohol, are high in calories but relatively low in nutrients, such as vitamins and minerals.

Eating healthily means including foods that are packed with nutrients rather than packed with energy.

You should reduce your intake of these foods as much as possible. You can do this by:

• Swapping sugary and fatty snacks for fruit, diet yoghurt or a slice of wholemeal toast with reduced-fat spread
• Choosing water, reduced-fat milk or low-calorie drinks instead of sugar-rich drinks
• Using only a scraping of spread on your bread and using an oil spray to limit fat when cooking

Alcohol contains around 7 kcal per gram. As well as adding calories to your diet, it can stimulate the appetite and weaken your healthy eating intentions.

For more advice on cutting calories, see How to lose weight.

A word about salt

On average, we eat over 50 per cent more salt than the recommended level and more than twice the amount we actually need.

We’ve become used to eating foods containing salt, so reducing the amount we consume often means adjusting our palates.

A lot of salt comes from processed foods, so look for low-salt varieties and check the salt content on the label. You can also cut salt by:

• Preparing foods from fresh ingredients as much as possible
• Avoiding salty snacks, such as crisps and salted nuts
• Choosing ‘unsalted’, ‘no added salt’ or ‘reduced salt’ foods