Side effects
Appetite loss and weight changes
Cancer and its treatment can affect your appetite and weight. Eating well helps you keep your strength, cope with side effects and recover.
Why it happens
The cancer itself, treatment side effects such as nausea, mouth sores, taste changes and fatigue, and feelings such as stress or sadness can all lower appetite. Some treatments, such as steroids and certain hormone therapies, can increase appetite and cause weight gain.
What helps
- Eat small meals and snacks every two to three hours, rather than three large meals.
- Choose foods high in protein and calories, such as eggs, yogurt, cheese, nut butters, beans and smoothies.
- Eat your biggest meal when you feel best, often in the morning.
- Drink between meals, not with them, so you don’t fill up on liquids.
- Try nutrition shakes if solid food is hard. Ask your care team which ones are right for you.
- Ask to see an oncology dietitian for a plan that fits your treatment.
When to call your care team
Call if you’ve lost weight without trying, you can’t eat for a day or more, or eating is painful or difficult.
Questions to ask your care team
Bring these to your next visit, or write down your own.
- Should I be trying to gain, keep or lose weight right now?
- Can I meet with an oncology dietitian?
- Are nutrition drinks right for me?
- Are there medicines that could help my appetite?
Go deeper
More detailed information
For more clinical detail, our affiliate, Northside Hospital Cancer Institute, covers this topic in depth.
Appetite loss and cancer treatment (National Cancer Institute)Sources
This page is for general education and does not replace advice from your doctor or care team. Last updated October 26, 2026.