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The Best Foods To Eat When You Have Breast Cancer

Stay hydrated, opt for fruits, veggies, whole grains and lean protein — and try to eat snacks and smaller meals throughout your day instead of larger portions

Bowl of assorted fruit and bowls of nuts and seeds

Whether you’re newly diagnosed with breast cancer or you’re facing breast cancer that has spread to another part of your body, you probably have a lot of questions and fears. And you want to do everything in your power to help your body fight back.


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A balanced diet helps ensure you’re getting the nutrients you need to keep you strong. But what should that entail? And just as importantly, what foods should you try to avoid?

Registered dietitian Anna Taylor, RD, LD, offers diet tips for undergoing cancer treatment, including what to eat and what to steer clear of.

Diet tips for breast cancer

Breast cancer treatment can have you feeling less than 100%, and your appetite may not be what it usually is. But it’s more important than ever to focus on the foods you’re putting into your body.

“A balanced diet supports a healthy immune system, balanced electrolytes and muscle mass,” Taylor says. “It also gives you energy and helps fight the fatigue that is so often associated with cancer treatment.”

Get enough calories

Remember to eat regularly throughout the day, choosing foods from the main food groups: Fruits, vegetables, protein, whole grains, healthy fats, and low-fat dairy.

Taylor suggests eating five to six small meals per day, as they’re less likely to trigger uncomfortable side effects like nausea, vomiting or diarrhea. Small meals also maximize your body’s ability to absorb nutrients.

“Our bodies can only absorb so much at one time,” Taylor notes, “so spreading things out with small frequent meals helps your body get the most out of every meal, which is especially important when you have breast cancer.”

Plus, she says that if you have a poor appetite, a large plate of food can be a total turn-off. A small meal or snack may be more appealing, making you more likely to actually eat it.

So, how can you know how many calories is enough? When you’re undergoing breast cancer treatment, forget food tracking and calorie counting. The best way to know whether you’re getting enough calories for energy is to weigh yourself once or twice a week.

If your weight is trending down week after week, speak with a dietitian to figure out an eating plan that works for you.

Pay attention to protein

Protein, which helps maintain lean body mass and muscle, is primarily found in:


Smaller amounts of proteins are found in vegetables and whole grains.

Trying to figure out how much protein you need? It depends on a lot of different factors, including age, weight, height and activity level.

“Everyone’s protein needs are different, but fighting cancer and going through cancer treatment increases your protein needs,” Taylor explains. “A good rule of thumb is to include protein at least three to four times per day if you’re eating normal portions of foods, or at least four to five times per day if you’re eating smaller-than-usual portions of foods.”

Examples include eggs with breakfast, Greek yogurt with lunch, chicken with dinner and cottage cheese or nuts as a snack.

Stay hydrated

Staying hydrated is always important, but it’s especially during breast cancer treatment. Some common side effects of cancer treatment can include vomiting, diarrhea, decreased appetite or fever, all of which can contribute to dehydration.

“If you’re vomiting or having diarrhea, an electrolyte replacement solution is a better way to hydrate than plain water,” Taylor says. “Otherwise, plain water is a great option.”

To keep hydrated, aim for at least 2 liters to 3 liters of fluid per day, or about 66 ounces to 99 ounces. Plain water is your best option, but other caffeine-free fluids can be a good choice, too.

“Your fluid needs are typically higher while going through cancer treatment, so sip fluids throughout the day,” she advises. “Staying hydrated will help you regulate your body’s temperature, blood pressure and electrolyte balance, help prevent or minimize constipation and allow your organs to filter out wastes and toxins.”

Breast cancer-fighting foods

When you’re facing breast cancer, you might feel tempted to bone up on vitamins and minerals via supplements. Instead, eat the rainbow — a rainbow of brightly colored produce, that is.

“No supplement can do the work of a varied diet, so don’t turn to pills to do it for you,” Taylor states. “Plant-based foods like fruits, vegetables, beans, grains, nuts and seeds are filled with phytonutrients, which are naturally occurring chemicals that support human health.

There are different types of phytonutrients, like carotenoids and flavonoids, and they do different things for your body. But what’s the rainbow got to do with it?

“Phytonutrients are largely what give produce its color,” Taylor explains, “so the more vibrant the color, the more likely it is to be filled to the gills with phytonutrients.” (There are exceptions, of course, like cauliflower and kohlrabi — bland-looking foods are still big on nutrients. Don’t count them out!)

Here’s a look at some common foods that contain important phytochemicals:


Food Source
Dark yellow/orange/green vegetables and fruits.
Food Source
Mustard, horseradish and cruciferous vegetables.
Phenolic compounds
Food Source
Garlic, green tea, soybeans, cereal grains, cruciferous vegetables and flaxseed.
Food Source
Most fruits and vegetables.
Food Source
Garlic, onion, leeks, shallots and cuciferous vegetables.
Food Source
Soybeans, legumes and flaxseed.
Food Source
Cruciferous vegetables (broccoli, cauliflower, kale, cabbage, Brussels sprouts).
Food Source

What to eat during breast cancer treatment

If your cancer treatment hasn’t caused any nutrition-related side effects that limit your ability to eat or digest food, Taylor says you can follow a generally healthy diet. Here’s what that should include.

Fruits and vegetables

Aim for five or more servings of fruits and vegetables each day. They contain antioxidants and anti-estrogen properties.

Cruciferous vegetables like broccoli, cauliflower, kale, cabbage and Brussels sprouts are rich in phytochemicals and especially good to include in your diet.

“Try to include a serving of produce with every meal and snack,” Taylor recommends. “At three meals and two snacks per day, for example, you’d get a total of five servings per day.”

Whole grains and other sources of fiber

Try to get 25 grams to 30 grams of fiber, like by eating whole grains — unprocessed foods that are high in complex carbohydrates, fiber and phytochemicals, as well as vitamins and minerals.

A study by researchers at Soochow University in Suzhou, China, found that high fiber intake may have a positive effect by altering the hormonal actions of breast cancer and other hormone-dependent cancers.

Make sure at least half the grains in your diet are whole grains like oats with breakfast, whole grain bread with lunch or brown rice with dinner.

“Another way to add fiber and complex carbohydrates is to choose nuts or seeds as a snack,” Taylor says. “You can also add legumes like beans, edamame, peas or lentils to meals.”

Lean protein — and soy, too

For good protein sources, increase your intake of poultry, fish and legumes like beans and lentils; minimize your intake of processed meats, like those that are cured, pickled and smoked.

A regular intake of processed meats is associated with an increased risk for certain types of cancer. Processed meats are also high in sodium, which can elevate your blood pressure in the short term.

Feeling skeptical of soy? Soy is safe in moderate amounts, which means you can eat one to two servings per day of whole soy foods (like tofu, edamame and soy milk).

Possible side effects and foods that can help

If you’re experiencing unpleasant side effects while you undergo breast cancer treatment, what you eat (and avoid) may be able to help lessen your symptoms. Here’s what may help.


If you’re having diarrhea, you may need to follow a low-fiber diet until it resolves. Make some temporary swaps, like:

  • Choosing refined grains instead of whole grains.
  • Peeling or cooking fruits and vegetables instead of eating them raw.
  • Eating nut butters instead of nuts.
  • Limiting or avoiding beans and lentils.


Taylor recommends eating small, frequent meals, which are often better tolerated than large meals. And, again, be sure to stay hydrated by sipping on water or an electrolyte replacement solution to replenish the fluids and electrolytes that your body is losing.

“Sip on fluids throughout the day rather than drinking large quantities all at once with meals,” she advises, “and talk to your healthcare provider to see if an antidiarrheal medication is appropriate.”


“An empty stomach can make nausea worse, so don’t skip meals entirely,” Taylor says. “Instead, focus on small bites of food throughout the day.” Your dietitian may also recommend that you:

  • Avoid strong flavors.
  • Have foods that are cool or room temperature, which don’t have a strong odor.
  • Eat lower-fat food, as fats take longer to digest.
  • Incorporate ginger root into your recipes.


If constipation becomes a problem, Taylor says your dietitian may advise you to do the following actions to encourage regular bowel movements:

  • Eat fiber-rich foods like whole grains, beans/legumes, fruits, vegetables, nuts and seeds.
  • Increase your fluid intake to at least 2 to 3 liters (66 to 99 oz.) per day. Being dehydrated can lead to fatigue.
  • Try some low-intensity walking. “This can help support the wave-like movements of the gastrointestinal tract, called peristalsis,” Taylor says.
  • Drink warm beverages like tea, which can help soften your stool.


People often experience more fatigue when they’re not eating well or when they’re losing weight during treatment. To combat fatigue, choose high-protein snacks and small frequent meals, rather than large meals.


Foods to avoid with breast cancer

You’re focusing on all the things you should eat, but it’s also important to know what foods you should avoid. Talk to your oncologist for exact recommendations, but for the most part, when you have breast cancer, you should avoid:

“Limit caffeine and alcohol, as both are dehydrating,” Taylor advises. “If you’re having diarrhea, consider avoiding them completely, as both can worsen symptoms.”

In fact, it’s best to avoid alcoholic beverages when possible, as it’s a known risk factor for breast cancer. A large observational study of 105,986 women suggested that drinking three glasses of wine or more per week throughout life increases a woman’s risk of breast cancer by a small but significant percentage.

The study saw a 15% increased risk of breast cancer when women drank an average of three to six drinks per week, compared to women who did not drink.

“Some studies tout possible benefits for heart health from moderate intake of red wine, but regardless of the type of alcohol, daily intake is associated with an increased risk of certain cancers, including breast cancer,” Taylor adds.

Ask for specialized guidance and support

“If you’re experiencing any side effect that affects your ability to eat regularly, ask your care team if you can meet with a dietitian to review individualized nutrition recommendations,” Taylor says.

Even if you’re not experiencing specific side effects related to food and eating, you may find it helpful to meet with a dietitian, especially one who specializes in cancer care.

“A dietitian can help you be sure you’re getting enough of the nutrients you need to help your body stay strong as you go through breast cancer treatment,” Taylor encourages. “We’re here to be another resource to you during a difficult time.”

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