A cancer diagnosis changes many aspects of life, including how people think about food. During and after treatment, nutrition becomes an important tool for healing, rebuilding strength, and supporting long-term health. Elise Cushman, LD, RD, a registered dietitian at Dartmouth Cancer Center (DCC), says good nutrition isn’t about perfection, fad diets, or miracle foods. Instead, it’s about using evidence-based guidance to nourish your body, reduce side effects, and regain a sense of control.
“Nutrition is not a cure for cancer,” Cushman says. “But it is a powerful way to support healing, energy, immunity, and overall quality of life.”
Why nutrition matters after cancer
Cancer treatment places major demands on the body. Surgery, chemotherapy, and radiation all increase the need for calories, protein, and fluids to repair tissue, rebuild muscle, and restore strength. Survivors may experience fatigue, appetite changes, nausea, taste changes, or digestive challenges that make eating difficult.
“Your body is in a hypermetabolic state during treatment, meaning it’s burning through fuel faster than normal,” Cushman explains. “Your nutrition needs are higher, even when eating feels hard.”
She points out that balanced meals that include protein, whole grains, healthy fats, and plenty of fruits and vegetables can help combat fatigue, promote healing, and restore energy. Survivors who prioritize nutrition often report better sleep, improved mood, and a faster return to daily activities.
A plant-forward approach
Experts recommend a “plant-forward” eating style, meaning fruits, vegetables, whole grains, and beans form the foundation of most meals. “This doesn’t mean you have to become vegetarian or vegan,” Cushman says. “It simply means plants take center stage.”
These foods are rich in fiber, a nutrient many Americans don’t get enough of. In fact, fewer than one in 10 people meet daily fiber recommendations. Fiber supports digestive health, helps manage blood sugar, promotes fullness, and may reduce inflammation and hormone-related cancer risks. “Fiber quite literally keeps things moving,” Cushman says. “And it plays a big role in gut health and overall wellness.”
A helpful guide is the American Institute for Cancer Research’s “New American Plate” method: aim for half your plate to be fruits and vegetables, one-quarter whole grains, and one-quarter lean protein, with healthy fats such as olive oil, nuts, or avocado in moderation. “Small shifts, like adding one extra vegetable each day, really add up over time,” Cushman adds.
Clearing up common nutrition myths
One of the most common misconceptions is that “sugar feeds cancer.” Cushman redirects this over-simplification to emphasize that all cells use glucose for energy. “Without glucose, our healthy cells wouldn’t survive,” she says. “The goal isn’t to eliminate natural sugars from fruits, dairy, vegetables, and whole grains. The goal is to limit added sugars.”
Another myth is that organic foods are required to prevent cancer. “The most important thing is simply eating more fruits and vegetables, regardless of whether they’re fresh, frozen, canned, organic, or conventional,” Cushman says.
Nutrition is about nourishment, not punishment. Progress over perfection is key.
Elise Cushman, LD, RD
Soy is another frequent concern, especially for people with hormone-sensitive cancers. “Soy causing breast cancer is a very big myth. Research shows that two to three servings of whole soy foods, such as tofu, edamame, soy milk, and tempeh, are safe and may even offer protective benefits,” she explains, also noting that sometimes people are a little standoffish toward tofu. “It's very neutral in flavor and works really well in dishes that you may already make. Chili, for example: cut the meat that you use in half, whether it's turkey, chicken, or beef, and replace it with tofu. You can break it up just like you would meat, and it'll absorb those flavors. I also like it in stir fry.”
Supplements: A tricky area
More than half of U.S. adults take supplements, but Cushman urges caution, particularly during treatment. “Supplements aren’t regulated the same way medications are, and some can interfere with chemotherapy or radiation,” she says. “Always talk with your care team before starting anything new.”
Vitamin D is commonly recommended, especially in northern climates, but other supplements may not be necessary — and some may be harmful. “Natural doesn’t always mean safe,” Cushman notes. “Also, be cautious of multi-level marketing of supplements, claims of ‘proprietary blends,’ and buzzwords like ‘premium,’ or ‘clean,’” Cushman says. “A higher price doesn’t necessarily mean higher quality, and vague claims such as ‘supports wellness,’ along with a lack of transparency about ingredient testing or sourcing, should all raise red flags.”
Protein, fluids, and gentle movement
Protein is essential for rebuilding tissue and preserving muscle. “Including protein at every meal is one of the best ways to support recovery,” Cushman says. Good sources include lean meats, fish, eggs, dairy, beans, tofu, nuts, and seeds.
Hydration is equally important. Survivors should aim for eight to ten cups of fluid daily, using water, herbal tea, broth, soups, milk, and hydrating foods. “If water doesn’t taste good, there are lots of other ways to stay hydrated,” she says.
Gentle movement also supports recovery. “Even short walks or simply getting outside can improve energy, mood, and quality of life,” Cushman adds.
Progress, not perfection
“Nutrition is about nourishment, not punishment,” Cushman says. “Progress over perfection is key.”
Cushman’s overall message is that survivorship is a journey, and food should provide strength, comfort, and confidence. DCC dietitians are available to offer personalized guidance and support.
“We’re not the food police,” Cushman says. “Nutrition is not about fear. We don’t care what size you are, and we don’t judge. We really just want you to eat, stay hydrated, and maintain your weight during and after treatment. Eating well is a form of self-care and self-nourishment. It's also a form of empowerment—and helping survivors regain a sense of control over their bodies is very important to us.”
This information was initially presented at DCC’s 2025 Survivor Symposium. Follow DCC on Facebook or check Dartmouth Health Events for updates and details on the 2026 event, coming this fall.