Weight loss

Weight lossYou can limit weight loss by making sure every mouthful has as many calories as possible.

Losing weight is a common side-effect of cancer. Cancer itself can cause changes to your appetite or to the way your body uses nutrients from food and drink.

Cancer treatments can also make it harder for your body to absorb what it needs from your food, and make it more difficult for you to eat in the first place – all of which can lead to weight loss.

What can help?

The best way to slow down or stop weight loss is to make sure each mouthful you eat and drink gives you as many calories (energy) as possible.

When you have cancer, you may also lose muscle, so it’s also important to choose high-protein foods that can help your body build muscle and repair tissue.

This page looks at how you can do this in the healthiest way possible, by opting for foods that are not only high in calories and protein, but are also beneficial for long-term health.

Please note, if your weight loss is rapid or severe, you should prioritise slowing down or stopping weight loss. This may mean eating high-calorie foods that aren’t generally considered to be healthy if they’re what appeal to you or are all you can tolerate.

Which foods to choose?

Foods that are higher in fat have more calories per mouthful. However, it’s still best to opt for foods containing healthier fats, such as oily fish, seeds and avocados.

It’s also best to avoid foods high in added sugar and salt, and highly processed foods, such as biscuits, chocolate, sugar-sweetened drinks, like cola, and fast foods like burgers, chips and fried chicken, and sugar-sweetened drinks like cola.

Guidance on …

Dairy foods

Dairy foods, such as milk, plain yoghurt and cheese, are a good source of calories, protein and important micronutrients like calcium meaning they can contribute to a healthy diet.

However, some dairy foods are particularly high in saturated fats, so to keep your intake of these less healthy fats down, it’s best to avoid butter, cream and ice cream.

Swapping butter for oil or oil-based spreads would help to reduce the amount of saturated fat you’re eating while still keeping the amount of calories high.

If you’re still losing weight, calories and protein intake should be your priority, so you may want to include some of these higher-fat dairy foods in your diet for the time being.

Red and processed meat

Red meat, such as beef, pork and lamb, is a good source of protein and important micronutrients like iron so can contribute to a healthy diet.

However, our research has shown that eating processed meat or too much red meat increases cancer risk. For this reason, we recommend eating moderate amounts of red meat and avoiding processed meat, such as ham, bacon, salami and hot dogs.

Fruit and veg

Fruit and vegetables are an important source of vitamins and minerals, which are good for our overall health. However, they tend to be quite low in calories and high in fibre, which means they can fill us up on few calories.

Make sure that you keep eating fruit and vegetables, but try to opt for higher-calories ones such as sweet potatoes, squashes, root vegetables – like parsnips – avocados, peas, sweetcorn, bananas and dried fruit.

Have a look at our shopping list for the healthier foods that we recommend.

Your shopping list

Red meat, eg beef, pork, lamb – eat in moderation

Poultry, eg chicken, turkey

Meat alternatives, eg tofu, soya

Non-oily fish, eg cod, haddock

Oily fish, eg salmon, mackerel


Pulses (beans and lentils)

Houmous and tahini

Nuts, seeds and nut butter

Full-fat milk or evaporated milk

Skimmed and semi-skimmed milk

Skimmed milk powder

Soya milk

Greek and natural yoghurt

Cottage cheese

Creme fraiche

Full-fat cheese


Vegetable oils for cooking or salad dressings

Vegetable oil-based spreads

‘Boosting’ your food

Here are a few ideas for increasing the calories and protein in your everyday food.

If you’re having…Add…
Puddings or breakfast cerealsNuts or seeds

Dried fruit


Whole milk or fortified milk (see below)

Natural or Greek yoghurt

Casseroles, meat dishes or soupsLentils or beans

Rice, noodles or pasta (ideally brown or wholewheat)

More lean meat, fish or meat alternatives, like tofu

More oil when cooking

Greek yoghurt or creme fraiche before serving

A serving of bread (ideally wholemeal) or potatoes with oil-based spread

Vegetables, mashed potatoes, beans or saucesOil

Whole milk or fortified milk (see below)

Oil-based spread


Egg (hard-boiled, or added when making savoury sauces)

Sandwiches, toast or crackersA thick layer of cream cheese, cottage cheese, nut butters or houmous

A filling of sliced avocado and tuna, or chicken

SaladsAvocado slices, nuts, seeds and pulses

Oil-based dressings

Oily fish, cooked lean meat or poultry


New potatoes

Hard-boiled egg

A serving of bread (ideally wholemeal) with oil-based spread


  • Try to eat little and often – you don’t have to stick to three meals a day. You could have a snack or small meal regularly, every two hours or so, including one before bed.
  • Keep high-calorie snacks and easy-to-prepare foods to hand at home and when you’re out and about.
  • Instead of steaming or baking your food, you could also increase the calories by cooking with oil, such as olive or rapeseed oil.
  • To get as many calories as you can from every mouthful, try to avoid clear soups, eating lots of fruit and vegetables or having a large drink just before or during mealtimes. These can fill you up without giving you many calories.

High-calorie drinks

Some people find having high-calorie drinks an easier way to boost their calories than eating snacks. It’s best to have these drinks after your meals, so you aren’t full before eating.

  • Fortified milk: add 2–4 tablespoons of skimmed milk powder to a pint (570ml) of whole milk. Keep it in the fridge for up to two days, or the milk’s ‘use by’ date, and use it in hot and cold drinks, in smoothies, on cereals and for cooking. This adds calories and protein without adding much volume.
  • Smoothies: make a smoothie by blending together fortified milk, yoghurt, fresh fruit – like banana, mango or berries – nuts, nut butter, seeds or avocado.  

Snacks you could try:

  • Nuts and seeds
  • Fruit loaf with oil-based spread
  • Wholemeal toast with nut butter and sliced banana
  • Full-fat natural yoghurt with seeds and/or dried fruit
  • Granola
  • Nut bars
  • Vegetable sticks or wholemeal pitta bread with houmous or guacamole
  • An open sandwich or bagel with scrambled egg, tuna or salmon

Stay as active as possible

When you lose weight, it is important to keep active. Certain types of physical activity can help build and maintain our muscle mass and strength. Do activities that you enjoy and can easily do, such as walking or cycling. Chores in and around the house are also good activities. Exercises to strengthen muscles under the guidance of an oncology exercise specialist or physiotherapist can help stimulate muscle growth and prevent loss of muscle mass and strength. You can also try to exercise at home.

What to do in case of severe weight loss?

In this situation, an extra intake of calories and protein should be the top priority. In this case, it is okay to eat foods that contain more saturated fat and sugar for as long as necessary. These foods can help you regain a healthy weight. Choose foods that you feel like eating. It is also important to eat small regular meals and snacks – aiming for every 2 hours is a good idea. You should also speak to your doctor or dietitian as they will be able to provide individualised advice to you.

Keep track of your weight. If you’ve made changes to your diet but keep losing weight or cannot put on any weight, ask your dietitian or doctor for more support.