Managing your diet

Energy is measured in calories. If we absorb more calories than our body needs, we put on weight.

To lose excess weight, you should control your calorie intake and keep active. This helps burn energy.

If you need to control your diet, it’s helpful to know about food types:

  • Fruits and vegetables are full of vitamins and low in fat. You should have 5 portions a day.
  • Starchy foods include bread, cereal, rice. They should make 1/3 of your calorie intake.
  • Fibre helps you feel full. Sources include peas, lentils and wholemeal bread and cereal.
  • Fish is a good source of protein and low in fat. You should have two portions a week.
  • Meat is high in protein, but can contain a lot of fat.
  • Dairy is a good source of protein and vitamins, but can also contain a lot of fat.
  • Fats are high in calories, so you should limit your intake of them.
  • Salt and sugar can be unhealthy in large quantities.

Learning more about a balanced diet will help you keep to a healthy weight.

Energy (calories)

Energy contained in food and drink is measured in units called kilocalories, or more commonly calories. On food labels you will see this written as kcal.

The recommended daily amount (RDA) of energy intake for adults is about 2,000 calories for women and 2,500 for men. We need less as we get older.

Two-thirds of the energy we should take in is used to control our body temperature and for other activities, such as digesting food or making new tissues. The rest of the energy we use up during physical activity. When we take in more energy than we use up, this is stored as fat and we gain weight.

To lose weight you need to burn off more energy than you take in. You can do this by:

  • reducing the amount of calories you take in through food and drink
  • increasing the amount of energy you burn off through physical activity.

Many weight loss programmes are based on calorie-controlled diets. This section looks at eating different food types in healthy amounts to help reduce the amount of energy you take in. This can help you lose weight, especially if you also increase your physical activity.

Know your food types

Few of us have time to check the energy content of everything we eat. But knowing about the different types of foods can help you to control what you eat and help with weight loss.

Fruits and vegetables

Fruit and vegetables are a good source of vitamins, minerals and fibre and are low in fat. Aim to eat at least five portions a day. One portion of fruit or vegetables can be:

  • one apple or banana
  • a slice of melon
  • two small fruits such as kiwi fruit or plums
  • a handful of berries
  • twelve chunks of tinned pineapple
  • a glass of orange juice (only counts once a day)
  • one whole vegetable such as an onion or small pepper
  • three heaped tablespoons of diced carrots or shredded cabbage
  • one cereal bowl of mixed salad
  • seven cherry tomatoes
  • two broccoli florets
  • three heaped tablespoons of peas or lentils.

To increase your daily intake of fruit and vegetables, try the following:

  • Have a mixed salad as a starter or as a side dish with your main meal.
  • Reduce meat portions and enjoy larger servings of vegetables and salad.
  • If you need a snack between meals, choose fresh fruit.

Try to avoid adding butter, rich sauces or dressings to vegetables and salads as this will increase the energy you take in. Frozen vegetables and tinned fruit in juice (not syrup) are just as nutritious as fresh ones and can be less expensive.

Starchy foods

Starch is a type of carbohydrate, which is a good source of energy. Foods like bread, cereal, rice, and pasta are starchy foods. Wholegrain varieties are better if you’re trying to lose weight as they make you feel fuller. Starchy foods should make up about one-third of what you eat in a day.

Potatoes are also included in this food type. Boiled or baked potatoes are healthier than deep fried chips. If you want to eat chips, use the low-fat oven varieties.


Increasing the amount of fibre in your diet can also help you feel fuller more quickly. Try changing to wholemeal bread and high-fibre breakfast cereals. Peas, beans, lentils, grains and seeds are other good sources of fibre, as well as fruit and vegetables.


Fish is a good source of protein, vitamins and minerals and is low in saturated fat. Aim to have at least two portions of fish a week. Grilling, steaming, poaching and baking fish is healthier than frying it. Frozen fish can be cheaper than fresh, but avoid high-fat fish-based processed meals or fish in batter. Tinned fish like tuna, sardines and pilchards are also low in saturated fat.


Although meat is high in protein and minerals, it can also be high in fat. Try to reduce your meat portions and have more vegetables instead. Choose cuts of meat that don’t have much fat, and grill or roast rather than frying. Skinned turkey or chicken is a healthier, low fat alternative to red meat such as lamb, beef or pork.

Try cutting down on processed meats, such as sausages, burgers, pies and sausage rolls, which are high in saturated fat.

Milk and dairy

Dairy products are good sources of protein, vitamins and calcium, but can also be high in fat. Try semi-skimmed or skimmed milk, low-fat spreads and yoghurt. Only use cream or butter in small amounts.


Sugars are a good source of energy and occur naturally in foods including fruit and milk. But foods such as sweets, biscuits, cakes, pastries and puddings have lots of added sugars. Fizzy drinks and alcohol also often contain a lot of sugar. Cutting down on foods and drinks with added sugar is important to help with weight loss.


Fats also provide us with energy, but are a concentrated source of energy and high in calories. There are two types of fats contained in foods:

  • saturated fats- such as fatty cuts of meat, sausages, pies, butter, ghee, cheese, cakes and biscuits
  • unsaturated fats- such as vegetable-based cooking oils and spreads, nuts, seeds, and oily fish such as sardines or mackerel.

Too much fat in your diet can be unhealthy and lead to weight gain and other health problems. Try to cut down on foods that contain fats but particularly saturated fat.

Food labels can give you a guide to this. If you have a choice, pick foods with unsaturated fats, but remember these are still a high-energy food. Even foods labelled as ‘low fat’ can still be high in calories.


Too much salt in your diet can lead to high blood pressure, which can cause heart disease and strokes. Try to eat no more than 6g of salt a day (that’s about a teaspoonful). Many processed foods and ready meals contain high levels of salt, so always check the label.

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