Medical Oncologist
Food and weight
Weight gain during chemotherapy
Because of the steroids, in most cases. They are given alongside many chemotherapy schedules to control sickness, and they sharpen appetite, hold fluid and change where fat is stored. Everyone arrives braced for weight loss, so gaining instead can feel like something has gone wrong. It has not, and this page explains what to do about it and what needs reporting.
NG
Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
17+specialists on panel
15,000+patients treated
35+centres across Telangana & AP
4.8★ / 800+Google rating
The short answer
Why are you putting on weight during chemotherapy?
Because of the steroids, in most cases. Steroids are given alongside many chemotherapy schedules to control sickness and reactions, and they increase appetite, hold fluid in the body and change where fat is stored. Weight going up during treatment is far commoner than people expect.
It catches families completely off guard. Everyone arrives braced for weight loss, and gaining instead can feel like something has gone wrong. It has not. It is a known effect of the supportive medicines rather than a sign about the cancer.
Who sees it most
It is particularly common in breast cancer treatment, where steroids, hormone treatments, reduced activity and disturbed sleep often come together. Being less active during treatment, and eating for comfort through a difficult few months, both add to it.
Some of the gain is fluid rather than fat. That part usually settles once the steroids stop.Where it comes from
The reasons weight goes up rather than down
Usually several at once. Knowing which ones apply to you is what makes it manageable.
Steroids
Given with many schedules to control sickness and reactions. They sharpen appetite considerably, encourage fluid retention and shift fat towards the face and abdomen. The effect is strongest in the days around each cycle.
Usually
- Hunger peaks for a few days after a cycle
- Settles between cycles
Fluid retention
Swelling in the ankles, legs, hands or face adds weight that is not fat. Some treatments cause it directly. Sudden swelling, or swelling in one leg only, should always be reported rather than accepted.
Swelling in one leg with pain needs checking the same day.Eating to settle nausea
Many people find an empty stomach makes sickness worse, so they snack constantly through the day. It works, and it adds up. Choosing what to snack on matters more than stopping.
Doing much less
Tiredness, time off work and family insistence on complete rest all reduce activity sharply. Muscle falls while weight rises, which is why people can gain weight and feel weaker at the same time.
Hormone treatments and early menopause
Where treatment brings on menopause or includes hormone therapy, weight tends to rise and redistribute. This is a longer-term change than the steroid effect and needs a different approach.
Disturbed sleep
Steroids in particular keep people awake, and poor sleep increases appetite the next day. Ask about the timing of the steroid dose, because taking it earlier often helps.
Not sure whether this applies to you?
Ask an oncologistThe honest answer
Does it matter, and what should you do about it?
During treatment, it matters less than you might think, and this is not the moment for a weight loss plan. Cutting calories while going through chemotherapy risks losing muscle and arriving at each cycle less able to tolerate it. Almost every oncologist will tell you the same thing: get through the treatment first.
What is worth doing now
Keep moving, gently and regularly, because that protects muscle and helps tiredness and mood as well. Choose snacks that are not only sugar, since steroid hunger is real and will not be argued away. Cut back on salt, which helps the fluid side. And keep the portion sizes ordinary rather than eating because it is there.
What to raise with your team
Sudden weight gain over a few days, swelling in the legs or face, breathlessness, or swelling in one limb only. Those are about fluid and sometimes about the heart, and they are assessed rather than dieted away. Also mention it if the steroids are keeping you awake, since the timing can often be changed.
Afterwards
Most of the fluid comes off within weeks of the steroids stopping. Fat gained takes longer and usually needs a deliberate effort once treatment is over — at which point a dietitian can help properly. Ask for that referral when you finish, rather than starting on your own halfway through.
Do not stop or reduce a steroid dose yourself. Steroids are tapered carefully and stopping abruptly is not safe.
!
One thing that cannot wait
Sudden weight gain over a few days, with swelling in the legs or face, breathlessness, or difficulty lying flat, needs to be assessed the same day rather than treated as a diet problem. So does swelling and pain in one leg only, which can mean a clot. Go to the nearest emergency department and say clearly that the person is on chemotherapy. Do not take a water tablet from home or from a relative.
Being straight with you
What this page cannot tell you
It cannot tell you how much of your gain is fluid and how much is fat. Those look identical on a scale and are managed completely differently. An examination, and sometimes blood tests, is what separates them.
It also cannot tell you whether to be trying to lose weight. For most people the answer during treatment is no, but that is not universal — diabetes, heart failure and some surgical plans change the picture. That is a conversation with your own team rather than a decision from a page.
What to do next
Weigh weekly and write it down, so a gradual rise can be told apart from a sudden one. Report any swelling, breathlessness or rapid gain rather than adjusting your diet. Keep moving gently. Ask for a dietitian referral for after treatment, and leave the serious effort until then.
Leave a number, we will call you
One field. No form to fill in, and no charge for the call.
Questions we are asked
Common questions about weight gain
Is it normal to gain weight during chemotherapy?
It is commoner than most people are told, particularly in breast cancer treatment. Steroids given to control sickness increase appetite and hold fluid, and doing much less than usual adds to it. It is an effect of the supportive medicines rather than a sign about the cancer.
Should I go on a diet to stop it?
Not during treatment. Cutting calories while on chemotherapy costs muscle, and arriving at each cycle weaker makes treatment harder to tolerate. Keep portions ordinary, choose snacks that are not purely sugar, keep moving gently, and plan any deliberate weight loss for after treatment.
The steroids make me constantly hungry. What can I do?
Accept that the hunger is real rather than fighting it, and steer it. Keep curd, fruit, roasted chana, nuts and soups within reach instead of fried snacks and sweets. The hunger usually peaks for a few days around each cycle and eases in between, so it is a short stretch rather than a permanent state.
My face has become rounder. Will it go back?
The rounding of the face associated with steroids usually settles over the weeks and months after they stop, though it can take longer than people expect. It is distressing and worth mentioning to your team, who can tell you how long you are likely to be on them and what to expect.
Can I take a water tablet for the swelling?
Not without your team prescribing it. Water tablets affect the kidneys and the body's salt balance, both of which chemotherapy is already stressing, and taking one from a relative's supply is genuinely risky. Report the swelling and let them decide what is needed.
Is exercise safe while I am on treatment?
Gentle regular activity is usually encouraged and helps tiredness, mood and muscle. Check with your team about intensity, particularly during the low-count days and if platelets are low. Walking is the safest starting point and does not need anything more than shoes.
Does weight gain mean the treatment is working?
No, and neither does weight loss mean it is failing. The scale reflects appetite, steroids, fluid and activity rather than what the cancer is doing. Whether treatment is working is judged on scans and tests. It is worth uncoupling the two in your mind.
When can I start losing the weight?
Usually once treatment has finished and you have recovered a little, and best done with a dietitian rather than alone. Much of the fluid comes off on its own within weeks of the steroids stopping, so it is worth waiting to see where you actually settle before making any plan.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
Patient stories
Hear it from people we have treated
Every story is a video, in the patient's own words. Nothing here is a written testimonial.
Sources
- National Cancer Institute — Nutrition in Cancer Care (PDQ)
- Cancer Research UK — Steroids and cancer treatment
- Macmillan Cancer Support — Weight changes during cancer treatment
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Talk to us
Noticed swelling or a sudden change in weight?
Tell us what has been found so far and we will help you reach the right specialist. One helpline serves every CION centre.