Changes in weight

Some cancer treatments, side effects or even lifestyle changes can cause you to gain or lose weight.

What can cause weight changes?

Some cancer treatments, side effects or even lifestyle changes can cause you to gain or lose weight. Talk to your specialist doctor, nurse or GP. They can refer you to a dietitian. A dietitian can review your diet and consider any specialist dietary needs you may have, such as food intolerances or allergies. They can give you advice about which foods are best for you.

If you have gained or lost weight, you may have body image concerns.

If you have lost weight

Many people with cancer find there are times when they cannot eat as much as usual. Sometimes this leads to weight loss.

There are lots of reasons for this. It can be related to the cancer itself, or to the side effects of different treatments. Some people do not feel hungry, or feel full soon after starting a meal. Others find that food makes them feel sick (nauseous), or that their treatment makes some foods taste different.

Some types of cancer make your body use up more energy, even if you are not very active. The cancer may produce chemicals that make your body work more quickly than normal. It may also produce chemicals that make your body break down fat and protein more quickly. This can make you lose weight, even though you may still be eating well. If you lose too much weight, it is important to talk to a dietitian.

The building-up diet

The building-up diet is high in energy and protein. It is specifically for people who have lost or are losing weight, or who can only manage to eat small amounts. Not everyone will be able to put on weight with this diet, but it should help to slow down or stop further weight loss.

Your doctor or dietitian may recommend foods that you would normally think of as unhealthy.

Adding extra energy and protein to your diet

If you do not have a good appetite, there are ways to add extra energy and protein to your diet without having to eat more food.

We have listed some foods that might help add extra energy and protein to your diet.

  • Fortified milk
    Adding extra energy and protein to your diet without having to eat more is called fortifying your food. You can make fortified milk by adding 2 to 4 tablespoons of dried milk powder to a pint (570ml) of full-fat milk and mixing it together. Keep it in the fridge and use it in drinks, on cereals and for cooking. You can use this instead of water to make soups, jellies, custards and puddings.
  • Cereals and porridge
    Make porridge with full-fat milk or cream. Add golden syrup, maple syrup, honey or sugar to your cereal or porridge. Try adding stewed or dried fruit too.
  • Casseroles and soups
    Add lentils, beans or noodles to casseroles and soups. Stir a tablespoon of cream into canned soups, or add energy and protein supplements. Grate some cheese over the heated soup, or drizzle some olive oil over the top. Try making packet soups using fortified milk.
  • Mashed potato
    Add butter or cream to mashed potato, and sprinkle grated cheese on top.
  • Vegetables
    Melt butter on hot vegetables and top with grated cheese or a chopped, hard-boiled egg. Or add a sauce made with fortified milk or cream.
  • Sandwiches
    Use plenty of butter or spread. Add a dessert spoon of mayonnaise or salad cream to thick sandwich fillings such as tuna, chicken, egg or cheese.

Below are some tips to add energy and protein to meals:

  • When you are shopping, choose full-fat foods instead of ‘diet’ or ‘light’ foods.
  • Fry your foods in oil, ghee or butter.
  • Add extra butter, margarine or oil to bread, potatoes, pasta and cooked vegetables.
  • Add extra cheese to sauces and extra paneer to curries.
  • Add cream, sour cream, plain yoghurt, mascarpone or crème fraiche to sauces, soups and meat dishes.
  • Add whole or blended beans, lentils or peas to curries and stews.
  • Add evaporated milk, condensed milk or cream to desserts and hot drinks.
  • Have cream or ice cream with desserts.
  • Add peanut butter (or other nut spreads), chocolate spread, tahini, honey or jam to bread, toast, crackers and biscuits.

Manufactured food (nutritional) supplements

There are many nutritional supplements available, which can add extra energy or protein (or both) to your diet. You can add them to your everyday foods, or they can be an addition to your normal diet. Sometimes they can be used to replace meals.

They come in many different flavours. If you have a dairy (lactose) intolerance, ask your GP, specialist nurse or dietitian to prescribe dairy-free food supplements. If you are diabetic, it is important to get advice from your GP, specialist nurse or dietitian before using nutritional supplements.

You can get some of these products from your chemist or supermarket, but your doctor, nurse or dietitian will need to prescribe some of them for you. High-protein or high-energy supplements should only be used with advice from your doctor or dietitian. They include:

  • Powdered drinks
    Some powdered drink supplements can be used to replace a meal. You can mix them with fortified milk or water. Some can be prescribed by your doctor. You can buy some products from your chemist and some supermarkets.
  • Milk-based supplements
    These are available on prescription in a variety of flavours, including sweet, savoury and neutral. The supplements usually need to be used within 24 hours. If you can only manage small amounts at a time, you can pour some into a glass and keep the rest in the fridge.
  • Juice-tasting supplements
    These ready-made, flavoured supplements are available on prescription. High-energy and juice-tasting supplements have a high sugar content. These drinks may not be suitable if you have a sore mouth or throat, as they may sting. If you have had radiotherapy for certain types of head and neck cancer, you may be more at risk of tooth decay, so it is best to avoid having sugar too often.
  • Fat-based liquids
    You can take these supplements separately in small doses, or you can add them to some foods.
  • Energy and protein powders
    Unflavoured powders are also available on prescription from your GP or dietitian. These are almost tasteless, so you can add them to different foods and drinks.

If you have gained weight

Don’t be too hard on yourself if you find you have put on weight. Sometimes, knowing why it has happened can help you think of ways to manage it.

After treatment, most people need time to recover. But as you gradually get better, you may find that you are ready to make some changes.

If you are having hormonal therapy as part of your treatment, it is important not to stop taking this, even if you think it is causing weight gain. Talk to your cancer doctor or nurse if you are concerned about this.

Before trying to lose weight, it is important to speak to your GP, cancer doctor or nurse. They can talk to you about the right approach for you, based on the cancer you have and its treatment.

If you want to lose weight

It is often better to lose weight gradually. You can talk to your doctor, nurse or dietitian about a suitable target for weight loss.

Knowing how many calories (energy) you are taking in will help you to lose weight. The NHS provides recommended daily allowances for men and woman of how many calories you should have for men and women. You need to burn off more energy than you take in to lose weight.

As well as eating healthy food, reducing how much you eat will also help you lose weight. Eating off a smaller plate, eating slowly and not having second helpings will all help you eat less.

Setting a target for weight loss

It is important to be realistic about how much weight you want to lose and over how much time. If you lose weight gradually, you are more likely to reach and stay at a healthy weight.

Most people put on weight over several months or longer, so the time to reach your target weight should be roughly the same.

To monitor your weight loss, weigh yourself weekly at the same time of day and using the same scales. If you find it difficult to get to your target, or if you reach it very easily, talk to your doctor, nurse or dietitian about setting a new one.