KEY TAKEAWAYS:
• Dietary patterns matter more than any single “superfood.” No individual food prevents or cures cancer. Research shows that a long-term pattern rich in fruits, vegetables, whole grains, beans and lean or plant-based proteins, while limiting processed meats, alcohol and highly processed foods, offers the greatest protection.
• Sugar does not “feed” cancer in the way many people fear. Every cell in your body uses glucose for energy, and avoiding sugar does not starve cancer cells. The real concern is excess calorie intake and weight gain, as obesity is linked to a higher risk of several cancers.
• Eating challenges during treatment can be managed with practical steps. For nausea, appetite loss and unintended weight change, dietitians recommend taking antiemetics as prescribed, eating five to six smaller meals a day, choosing higher-calorie and high-protein foods, and using nutritional supplements when needed.
• An oncology dietitian can help at any stage of the cancer journey. Nutrition needs shift before, during and after treatment. You can request a referral at diagnosis, during active treatment or as you move into survivorship to get realistic safe, and personalized guidance.
SUMMARY:
OhioHealth oncology dietitians Lauren Hinze, MDN, RD, LD, and Savannah DeAnthony, MS, RD, LD, answer common questions about cancer-risk-reducing diets, the sugar-cancer myth, and managing nausea, appetite loss, and weight change during treatment. The article offers grounded, judgment-free guidance and explains when to seek support from an oncology dietitian for a nutrition plan tailored to your needs.
Nutrition is one of the most common topics that comes up for people facing a cancer diagnosis, and one of the most misunderstood. From “superfoods” that claim to fight cancer to warnings about sugar feeding tumors, it can be hard to know what to believe. What you eat can play a meaningful role in cancer prevention and in how well your body tolerates treatment, but the full picture is more nuanced than most headlines suggest.
Lauren Hinze, MDN, RD, LD, an oncology dietitian at the OhioHealth Cancer Survivorship Clinic, and Savannah DeAnthony, MS, RD, LD, an oncology dietitian at OhioHealth Arthur G.H. Bing, MD, Cancer Center at Riverside Methodist Hospital, answer your most common questions about diet, cancer risk and eating well through treatment and beyond.
How much can diet realistically influence a person’s cancer risk — and where does that influence end? What do you wish more people understood about that boundary?
DeAnthony: Diet is one of several lifestyle factors that can influence cancer risk, but it is important to remember that cancer is complex. No single food can prevent or cause cancer on its own. Genetics, age, environmental exposures, tobacco use, alcohol, physical activity and other factors all play a role, too. What we do know is that long-term dietary patterns matter. A plant-based diet and eating a variety of fruits, vegetables, whole grains, beans and lean sources of protein while limiting processed meats, red meat, alcohol, sugar-sweetened beverages and highly processed foods can help reduce the risk of several types of cancer. Maintaining a healthy weight through balanced nutrition and regular physical activity is also an important part of cancer prevention. Ultimately, diet is one piece of the overall picture.
When people hear “cancer-fighting foods,” what does that phrase actually mean clinically? Is there real evidence behind specific foods, or is it more about overall patterns?
DeAnthony: The term “cancer-fighting foods” can be misleading because there is not a single food that has been proven to prevent or cure cancer. Instead, research consistently shows that overall dietary patterns have the greatest impact on long-term health. Many plant-based foods contain vitamins, minerals, fiber, and phytochemicals that may help protect cells from damage, support a healthy immune system, and reduce inflammation. Rather than focusing on one “superfood,” it is more beneficial to eat a wide variety of colorful fruits and vegetables, whole grains, legumes, nuts, and seeds as part of a balanced diet. The goal is not perfection or finding one miracle food. It is building consistent, healthy eating habits over time that support your overall health and may help reduce cancer risk.
Hinze: Evidence does show that eating foods that contain antioxidants help to reduce inflammation within the body and decrease oxidative cell stress which can increase risk for cancer. Just to name a few — some of the foods high in antioxidants are berries, leafy green vegetables, nuts and seeds and olive oil. Eating a well-balanced diet and staying physically active are healthy habits that do help prevent or “fight” cancer.
What are the most common eating challenges you see once treatment starts — nausea, appetite loss, taste changes — and how do you help patients work through them day to day?
Hinze: The most common eating challenges I see once treatment starts are nausea, vomiting and appetite loss. I like to prepare my patients prior to starting treatment with education on specific side effects of treatment and nutrition tips. Even if they are not currently having any side effects or symptoms, I like them to be prepared and have the resources to look back at if, and when, it does happen.
Once a patient starts to have eating challenges, I typically like to provide gentle suggestions, support and further education. For nausea and vomiting, I recommend first taking antiemetics regularly (as prescribed by their care provider) and even preventatively if they notice it happens in a pattern (like 1-2 days right after treatment). Once they have a good regimen with an antiemetic and are controlling the nausea or vomiting, I recommend eating comfort foods or whatever sounds good. I remind them eating something is always better than eating nothing at all.
Most nausea leads to a loss of appetite, but sometimes the loss of appetite can happen on its own. My recommendation for those patients is to eat smaller more frequent meals (5 to 6 times daily), focusing on high-protein foods, and trying to incorporate some kind of nutritional supplement like Boost or Ensure to help prevent any weight loss.
There’s a persistent claim that sugar “feeds” cancer cells. What would you want someone to understand about where that idea comes from and what the evidence shows?
DeAnthony: This is one of the most common nutrition questions I receive. The idea comes from the fact that cancer cells use glucose (sugar) for energy. However, so does every healthy cell in your body, including your brain, muscles and organs. Your body should naturally maintain blood glucose levels regardless of whether you eat sugar, so completely avoiding sugar does not “starve” cancer cells. The bigger concern is overall dietary pattern and maintaining a healthy weight. Regularly consuming large amounts of sugary foods and beverages can contribute to excess calorie intake and weight gain, and obesity is associated with an increased risk of several types of cancer. For most people, there is no need to fear sugar or eliminate it completely. Instead, focus on a balanced eating pattern that includes plenty of nutrient-rich foods while limiting added sugars.
How do you think about weight change during treatment? What do you tell patients who are losing weight without trying, versus those told to watch their weight?
Hinze: During treatment, I tell most of my patients that the goal is to maintain weight or to minimize significant unintentional weight loss as much as possible. If a patient is losing weight without trying, I revisit nutrition recommendations like eating smaller, more frequent meals, choosing higher calorie foods (like whole milk instead of skim), drinking high-calorie protein drinks and taking antiemetics.
I remind patients frequently through their treatments about the importance of maintaining weight. Significant weight loss can lead to malnutrition which can decrease their ability to tolerate treatments. This is due to nutritional status, low energy and decreased strength. Some patients that are on steroids do gain weight during treatment and so, I recommend to those patients to decrease snacking on high-calorie and high-sugar foods.
Are there specific foods, supplements or diets (keto, juice cleanses, high-dose vitamins) patients should be cautious about during chemotherapy or radiation?
Hinze: There are no specific diets that I recommend my patients to be using during chemotherapy and radiation. Because there are so many side effects that will likely prevent normal nutrition intake, I recommend a normal, balanced diet most of the time. If a patient starts a new supplement, I always recommend that they first speak with their care provider to make sure there are no medication contraindications before taking. The only supplement I typically recommend is a fiber supplement if a patient is having difficulty with constipation or diarrhea. The only foods that I give caution about, due to oncology patients lowered immunity, are foods that can increase risk of food borne illnesses like raw honey, raw fish, deli meats and fresh produce. I recommend avoiding raw honey, limiting raw fish and deli meat, washing fresh produce with water only, and to avoid purchasing produce with cuts, deformities or visible debris and mold.
For someone newly diagnosed, what’s one piece of food-related advice you give in the very first conversation?
Hinze: One piece of food-related advice I give to someone who is newly diagnosed would be to prioritize nutrition on the good days before, in between and after treatment days. I remind them that nutrition is what will help them to maintain their weight, help with energy and strength, and help them to better tolerate treatments overall. I also remind them that we are here as a resource for them to help them overcome any nutrition challenges they may have during treatment.
When should someone ask their care team for a referral to an oncology dietitian, rather than trying to figure out nutrition on their own?
Hinze: We typically receive a lot of referrals from care providers and nurses right at the time of diagnosis. If someone was not referred already, I would recommend that they ask for a dietitian at any point during their treatments.
DeAnthony: I encourage anyone with a cancer diagnosis to ask about seeing an oncology dietitian, whether they are preparing for treatment, actively receiving treatment or transitioning into survivorship. Nutrition needs can change throughout the cancer journey, and recommendations are often individualized based on the type of cancer, treatment plan, side effects and overall health. An oncology dietitian can help you sort through the misinformation and create a nutrition plan that is realistic, safe, and tailored to your specific needs and goals.
What should I eat after cancer treatment to regain strength and support recovery?
DeAnthony: Recovery looks different for everyone, but the goal after treatment is to rebuild strength, support healing, and establish long-term habits that promote overall health. Focus on eating regular, balanced meals that include lean or plant-based proteins, whole grains, fruits, vegetables and healthy fats. Protein is important for rebuilding and maintaining muscle, while fruits and vegetables provide vitamins, minerals, fiber and antioxidants that support overall health. Staying hydrated and gradually returning to physical activity, as recommended by your care team, can also help improve energy and strength. Rather than following restrictive diets or searching for a “perfect” way to eat, I encourage cancer survivors to focus on sustainable habits that they can maintain long-term. Small, consistent changes often have the greatest impact on health and quality of life.
Get to know the experts
What drew you to oncology nutrition specifically, out of all the directions a dietitian could go?
Hinze: I was drawn to oncology nutrition, and specifically outpatient oncology, because I liked the connections I was able to make with my patients. I felt that I was able to be a part of their journey, help them overcome hardships and any obstacles they may face. I like to think that I make my patients feel heard, supported and motivated during their cancer journey.
DeAnthony: My interest in oncology nutrition is personal. My grandma passed away from glioblastoma when I was in middle school, and watching what she and my family experienced gave me an appreciation for how important compassionate, supportive care can be. It inspired me to pursue a career where I could help patients navigate one of the most challenging times in their lives. I love being able to provide practical, evidence-based nutrition guidance while building relationships with patients and helping them feel supported throughout their cancer journey.
Outside of work, what’s a meal or dish that brings you comfort?
Hinze: Macaroni and cheese.
DeAnthony: Almost any home-cooked meal made by my mom. Growing up, she prepared countless homemade meals for our family, and those experiences are a big part of what sparked my interest in nutrition and ultimately led me to become a dietitian. To me, food is about so much more than nourishment. It is about bringing people together, creating memories and showing care for the people you love.
