Why is Nutrition Important? [Podcast]

Why is nutrition so important, and what should cancer patients should keep in mind during and after treatment? With the help of Stacy Kennedy, MPH, RD/LDN, CSO, senior nutritionist at Dana-Farber Cancer Institute, we debunk a few nutrition myths in this podcast — and provide tips on what you can do to eat healthfully.

Austin Fontanella: Let’s just jump right in: Why does nutrition need to be a top priority for cancer patients?

Stacy Kennedy, MPH, RD/LDN, CSO: As you mentioned, nutrition is something that’s important for everyone, but during cancer treatment it’s especially important to make sure that you’re getting the nutrients that your body needs. Keep in mind, our nutritional requirements can actually be a little bit different during treatment. You also need to think about optimizing and supporting the immune system. And so feeling really good every day and helping support your body to be at its best are all things that nutrition can play a role in.

Fontanella: Going off of that, is it possible to boost your immune system or maybe speed up your treatment recovery process by eating the right types of food?

Kennedy: Yes and no. I think one of the ways we approach this with patients is helping to manage side effects and symptoms. Things like nausea or digestive upset like constipation or heartburn, fatigue — these are all things that can come up during treatment and with proper nourishment you can really help to mitigate the severity, or sometimes even the duration of these side effects.

As far as the term “boosting the immune system,” I feel like that starts to go into the world of what we call internet nutrition for lack of a better word. We like to say support the immune system. Boosting makes it sound like, you know, it’s just living up to something it’s a little hard to describe. We want to really use nutrition to be supportive of all of the basic functions that our body does, and really kind-of optimize how you can feel each day.

Fontanella: Going back, regarding side effects that either come from cancer or the treatment. Do you have any advice for either patients or caregivers in order to help cope with these?

Kennedy: Yes, lots. A lot of what we do individually with patients is a little bit of like nutrition investigation. We try to help figure out within certain kinds of categories what specific foods, specific beverages, and eating patterns might be most helpful. There are also some tried and true strategies, depending on the symptom, and a lot of that information is on the website.

For example, for nausea, make sure you don’t have an empty stomach — eating small, frequent meals can help there. Things like lemon and ginger may also help with nausea management. Don’t forget about hydration. Getting the right balance of fiber from your diet can be important for constipation.

There are also a lot of nuances in certain foods. Whatever your typical eating pattern is, your taste preferences, your cultural eating habits, there are ways to apply the sort of principals of nutrition for symptom management and come up with a custom food list that really works for each person.

Fontanella: Would it make sense to make a log and write this stuff down to let yourself know what worked and what didn’t work?

Kennedy: Yeah, I think it can be helpful especially if you’re meeting with a nutritionist to keep track. Sometimes keeping track just for the sake of keeping track, it’s an awful lot of work, can be somewhat frustrating and tedious. However, it can also be a really effective tool when you’re trying to develop a new habit.

If you’re struggling with appetite and you’re going through treatment, keeping track might help you remember; or even better, set an alarm on your phone to remind you it’s time to eat or drink. You can then bring some of those records in to show your nutritionist and or your doctor, and they can kind of use that as a tool. However, keeping a journal every day forever and ever, it’s not for everyone.

Fontanella: That makes a lot of sense. If someone came to you and asked, “What should I be eating?”, is there a broad diet you give all cancer patients that they should try to follow?

Kennedy: The foundation is really a well-balanced plant-based diet. What we mean by that is that you have these kinds of partnerships on your plate. You’re trying to make half of your plate vegetables or fruits, a quarter of your plate protein, and that might be something like chicken, fish, or eggs. It could also be nuts, seeds, beans, or something like a nut butter. And then the other quarter is a carbohydrate, so a healthy starch. This could be a baked potato, quinoa, brown rice, or things like that.

Now, that’s kind of a general, healthy, balanced plate, but there often are times during treatment or due to the cancer itself that patients will need to make modifications. So, while getting a lot of vegetables, whether they’re raw or cooked, is a generally healthy thing to do, sometimes patients actually need to have less fiber. If that’s the case, we recommend more cooked vs. raw vegetables. There are a lot of ways to customize it, but that overall plant-based foundation with adequate protein is something that we do generally recommend for most people.

Fontanella: Those are some of the things you should be eating. Are there any foods that you should be avoiding?

Kennedy: I mean, first and foremost are things that you’re kind of adverse to. So, don’t force yourself to get something down just because you read online, or somebody told you that it’s really good for you. Bring those questions to the nutritionist. In terms of things to avoid from a cancer prevention standpoint, it isn’t all or nothing. Rather, it’s really the balance of things overall.

We know that excessive amounts of red meat can increase the risk of developing certain kinds of cancers like colorectal cancer. Having excess amounts of processed meats might be risky in terms of certain types of cancers as well. So, there’s a lot of good data, even on managing weight, trying to exercise, eating a healthy, balanced diet, to avoid obesity as a way of maybe reducing risk for developing certain kinds of cancers. But as far as hard and fast rules, it really becomes individualized. I think for people in treatment it can be challenging already just to eat. So, if we have this really long list of things to avoid, sometimes, just the overall thought process of that can be challenging.

Fontanella: It really sounds like you’ve got to do what’s best for you, and whatever helps you get through it, start with that and then you can work from there.

Kennedy: Yes, to some extent. However, there’s the other side of that coin — eat whatever you want. That can also be hard for people to hear. If you feel like eating an ice cream, great, like everything else things in moderation are fine. But sometimes patients get that message of one or the other. Either there’s a very defined food list of dos and don’ts, or it doesn’t matter, do whatever you want. It’s kind of like that game two truths and a lie.

That’s where it helps if you can meet with someone to kind of customize it. There’s something in between those two things. There certainly are general guidelines. If you ate ice cream for breakfast, lunch, and dinner every single day, that’s not really recommended either. So, there is something in the middle of that, but we want the foundation to be a colorful array of plant-based foods as kind of that foundational element.

Fontanella: Absolutely. And moving from patients who are no longer on treatment or are survivors, are there any nutritional recommendations or things they should keep in mind as they continue their diet going forward?

Kennedy: Yes, absolutely. Again, there will be some, you know, personalization components, but that balanced plate and having those plant-based foods is important. Think a Mediterranean-style diet where you’re including healthy fats, things like olive oil, avocados, nuts, seeds, and hummus along with fish and eggs. In addition, you want to be getting those whole grains and lots of veggies. That really is the recommendation, along with physical activity and hydration.

You know, we didn’t talk too much about that but getting enough water, getting enough fluids, is really important throughout treatment and after treatment as well.

Fontanella: In terms of hydration, what should you be aiming for?

Kennedy: It really depends because everybody has a different fluid need. The 8-ounce cups a day rule is to some extent made up. I mean, the math works for some people, but if you’re more active, if you’re a bigger person, if you’re having issues like diarrhea, you might need more than that.

Remember, you can count things that are liquid at room temperature. So, if you drink a smoothie, if you have an herbal tea, if you have soup, those count towards your fluid requirements, and adding fruits or citrus to water can increase the palatability and also some of the nutrients as well.

There are a lot of strategies. I would say most people self-report that they struggle to get enough fluid, and I believe it. I think it’s something you have to really be mindful about and kind of make into like a new habit. But it can really help a lot, especially with things like energy level and really, you know, feeling good.

Fontanella: Just to come full circle now, we talked about stuff that is scientifically proven. If you go online though, it’s really easy to find all these claims that either certain foods can prevent or maybe even cure cancer. How should people approach the stuff that they find online?

Kennedy: The first step is to collect that information and bring it to your trusted advisor. So, if you have a dietician you work with, that’s a great person to bring it to. You can also talk to your oncologist, or your nurse practitioner. It’s hard when you’re being bombarded with all of those messages, and nutrition can make a really strong impact, but there should never be a case where somebody’s out there promoting that a certain kind of diet can cure cancer.

When we start to see those sorts of absolute language, or certain claims regarding supplements and vitamins, you know we really want to stay in the realm of evidence-based practice. We understand that nutrition and eating habits can be very supportive and be very beneficial, but we’re not going to start making claims that are absolute like completely prevent or cure. That really can be misleading and technically I think is illegal, so I do recommend caution.

At the same time, I really want patients to have a place to come talk those things out. Trust me, I’ve heard so many different things over the years that there’s nothing that’s going to be shocking or surprising or that you’re going get a response like, “Why would you think that would be helpful?” When you’re going through something like cancer, you want to be open-minded, and so as your provider we want to be open-minded too.

Bring in those conversations so we can really look at it more from a personal angle and really help you to know how to handle when somebody comes to you, and says, “Hey, I love you, you’ve got to do this.” And you’re like, “Thank you, and I’m going to go talk to my nutritionist about that.”

Fontanella: To wrap things up here, are there some verified online sources or a place you can direct people to if they have questions, or are just looking for information?

Kennedy: Absolutely. First and foremost is the Dana-Farber Nutrition website. We have a lot of really great information, and a lot of recipes. Simply visit danafarber.org\nutrition; within our website we also have a list of other reliable resources for information such as links to the National Cancer Institute, American Cancer Society, and American Institute for Cancer Research. We have a whole list of places where you can absolutely get more reliable information on your own, especially where it can be hard to get an appointment to sit one-on-one sometimes.


During the episode, Kennedy discusses the benefits of working with a nutritionist. She is referring to a licensed nutritionist or a registered dietitian with oncology experience. Patients should always make sure they’re working with a reputable practitioner who has undergone the proper academic training.

If you are receiving treatment at Dana-Farber, your doctor’s scheduling office can book you a one-on-one visit with a nutritionist. Otherwise, you can search the Academy of Nutrition & Dietetics’ website to find a licensed nutrition provider in your area.