Eating to Keep Weight On During Cancer Treatment

This page is for people in cancer treatment who are losing weight without trying, and for the people who cook for them. It explains why weight drops, how to get more calories and protein from small amounts of food, and when to call your team.

Treatment can lower your appetite, change how food tastes, and cause nausea, mouth soreness, or fatigue. Meanwhile your body is working hard and may need more calories and protein than usual. That combination is why many people lose weight without trying. Losing weight this way is not a sign you are doing something wrong. It is worth telling your care team about, because they can help before it affects your strength or your treatment.

When appetite is low, the goal shifts. Big meals give way to steady, easy nourishment. Many people do better with small meals and snacks every couple of hours. Eat the most when you feel best, which is often in the morning. Keep easy, high-calorie foods within reach. Eat by the clock rather than waiting to feel hungry. Drinks like milk, smoothies, or nutrition shakes count too, and they can be easier than solid food.

You can pack more nourishment into small amounts of food. Cancer dietitians often suggest adding whole milk, cheese, nut butters, olive oil, avocado, or cream to foods. Choose full-fat versions during treatment. Eat the protein first, while your appetite lasts. This is the opposite of everyday diet advice, and that is on purpose. During treatment, holding your weight and muscle usually matters more than cutting calories or fat.

Small changes at home help, but your care team can do more. Tell your team if you keep losing weight, if you cannot eat for a day or more, or if you feel weaker. They can look for treatable causes and adjust your anti-nausea or other supportive medicines. They can also refer you to an oncology dietitian, a dietitian who specializes in people with cancer. Sometimes they will suggest oral nutrition supplements or other support.

NCI gives a clear trigger: report a weight loss of more than 3 to 5 pounds in one week. NCI says to tell your doctor right away about a sudden gain, such as 5 pounds in a week.

Read this page as general background rather than a plan for you. A dietitian can build the calorie and protein targets that fit your own body and treatment.

Some problems cannot wait for a routine visit. Match what is happening to the right level of help below.

• Call 911 or go to an emergency department if you are too weak, confused, or drowsy to drink, or if you faint. Do not drive yourself.
• Call your treatment team at once, day or night, if your temperature hits 100.4°F (38°C) or higher while you are having chemotherapy. CDC calls that a medical emergency. Fever may be the only sign of an infection, and infection during chemotherapy can be life-threatening. If they cannot be reached quickly, go to an emergency department and say you are having chemotherapy.
• Call your care team the same day if you cannot keep food or fluids down for a day.
• Call your care team right away if you are hardly passing urine, or it is very dark yellow or amber. MedlinePlus lists these as signs of severe dehydration. Also call right away if you gain weight suddenly, such as 5 pounds in a week, or your legs, feet, or belly swell suddenly.
• Call your care team within a day or two if you have lost more than 3 to 5 pounds in a week. Also call if you are weaker or more unsteady on your feet than last week. Call too if pain, nausea, or a sore mouth is what is stopping you eating. Those causes can often be treated.

• National Cancer Institute — Weight Changes, Malnutrition, and Cancer
• National Cancer Institute — Nutrition During Cancer Treatment
• National Cancer Institute — Eating Hints: Before, during, and after Cancer Treatment
• MedlinePlus — Dehydration
• CDC — Fever and Cancer Treatment