Weight changes

Some cancer treatments lower the amount of sex hormones in the body. These hormones are oestrogen and progesterone in women and testosterone in men.

Low levels of sex hormones can sometimes make you put on weight.

After the menopause the way that fat is distributed around the body changes. Extra weight tends to build up around the waist, rather than on the hips and buttocks. This change is caused by a drop in oestrogen levels.

But weight gain is usually caused by a combination of factors, including diet and exercise. You might begin to notice a change in your body shape if treatment for cancer has put you into the menopause or if the treatment blocks the action of oestrogen.

This change in body shape can be difficult to cope with.

Coping with weight changes

You might be able to have hormone replacement therapy (HRT) to control symptoms caused by low levels of sex hormones. But you can’t take HRT if you are having breast cancer treatment that aims to stop the body producing sex hormones or block their action.

Changes in weight can affect your confidence and self esteem. Trying to make changes to your diet and starting or increasing exercise when you aren’t feeling at your best can be difficult. Treatments for cancer, including hormone treatments can cause tiredness which may make exercising more difficult. And this can add to weight gain.

Hormone symptoms, such as hot flushes and sweats, can also make it more difficult to cope. Take things one step at a time and talk to your doctor or nurse about any problems you have.

Exercise, muscle mass and weight gain

Changing your diet and being more physically active may help you to maintain your normal weight.

Physical activity can help to maintain muscle strength, but it needs to be a combination of aerobic and resistance exercise.

Aerobic exercise is any exercise that makes your heart and lungs work faster to provide more oxygen to the muscles for example walking or gardening.

Resistance training includes weight training and swimming. You have to use your muscles to push against the weights or water, which helps to strengthen them.

Talk to your doctor or specialist nurse before you start if you aren’t normally very physically active. They can help you work out what is best for you.

Physical activity also helps to control your weight. You don’t have to go to the gym, you can build it into your life. For example, you could get off the bus the stop before you need to, do some gardening or join a walking group. Some hospitals organise exercise sections for cancer patients. Ask your specialist nurse if this is available. 

You should aim to be physically active for 30 minutes 5 days a week. Your doctor may check your cholesterol and heart health before you start an exercise plan. This is important if you have conditions such as diabetes or you are overweight.

Hormone treatment may lower your bone density, increasing the risk of fractures. Talk to your doctor if this could be a problem for you.

Eating a balanced healthy diet can help you to maintain a healthy weight. It can also help you lose or put it on if you need to.

This page is due for review. We will update this as soon as possible.

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