Breast Cancer Prevention: What Dr. Kristi Funk Wants Us to Know

At a previous Plant Stock event, we had the privilege of learning from some of the brightest minds in lifestyle medicine. Among them was Dr. Kristi Funk — world-renowned breast cancer surgeon, best-selling author, and passionate advocate for helping women understand the choices that can influence their health.

Her message was both sobering and empowering: while no lifestyle can guarantee that someone will never develop breast cancer, there are meaningful steps we can take to reduce risk.

And many of them begin with what we put on our plates.

Breast Cancer and the Power of Prevention

Breast cancer is now the most commonly diagnosed cancer worldwide, which makes understanding prevention more important than ever.

Of course, some breast cancer risk factors are outside our control. We can't change our age, genetics, family history, or the breast tissue we were born with.

But those aren't the only factors that matter.

Researchers estimate that a substantial proportion of cancers could potentially be prevented through modifiable behaviors and exposures, including tobacco avoidance, maintaining a healthy body weight, physical activity, limiting alcohol, and eating a health-promoting diet.

That's where Dr. Funk encouraged us to focus.

Instead of viewing cancer prevention as something mysterious or completely outside our control, we can ask a much more useful question:

What can I do today that may help create a healthier environment inside my body for the years ahead?

Why Whole Plant Foods Matter

When we talk about eating to support long-term health, we're not talking about one magical vegetable, supplement, or "superfood."

It's the overall dietary pattern that matters.

Vegetables, fruits, intact whole grains, beans, lentils, and other minimally processed plant foods deliver something remarkably difficult to reproduce in a pill: a complex package of fiber, vitamins, minerals, antioxidants, phytochemicals, and other compounds that interact with our bodies in countless ways.

A diet centered around these foods can also naturally displace foods that tend to be higher in saturated fat, added sugars, and calories while being low in fiber.

That distinction matters because cancer doesn't develop in isolation. Metabolic health, inflammation, hormone signaling, body weight, gut health, and other biological processes all contribute to the environment in which our cells live.

The goal isn't to find one food that "prevents cancer."

It's to build a dietary pattern that consistently supports health.

Fiber Deserves a Much Bigger Conversation

One of the simplest ways to improve the quality of your diet is to eat more fiber-rich foods.

Fiber is found exclusively in plant foods, and most Americans eat far less than recommended.

Why does fiber matter?

First, fiber supports regular digestion and feeds beneficial microbes living in the gut. Those microbes transform components of our food into compounds that can influence immune function, metabolism, and the health of the intestinal lining.

Fiber may also play an important role in hormone metabolism.

Estrogen is processed by the liver and excreted into the digestive tract. Fiber can help carry waste products through the intestines and out of the body rather than allowing some compounds to be reabsorbed.

This is one reason researchers continue to investigate the relationship between high-fiber dietary patterns, circulating hormones, and hormone-sensitive cancers.

The practical lesson is refreshingly simple:

Put beans, lentils, whole grains, vegetables, and fruit on the menu every day.

Rather than obsessing over a fiber supplement, build meals around foods that naturally contain it. (And....Plant Strong is here to help make it easy.)

Your Gut Is Part of the Conversation, Too

Fiber also introduces us to another fascinating area of cancer research: the gut microbiome.

The trillions of microorganisms living in our digestive system aren't simply passengers. They interact with the foods we eat and produce metabolites that can influence processes throughout the body.

Researchers are even studying a collection of gut bacteria sometimes referred to as the estrobolome because of their potential role in estrogen metabolism.

We still have much to learn about these relationships, but the practical advice is remarkably consistent with what we already know about cardiovascular and metabolic health:

Feed your gut a wide variety of fiber-rich plant foods.

Instead of asking, "What's the best food for my microbiome?" try asking:

How many different whole plant foods can I eat this week?

Beans. Oats. Barley. Berries. Apples. Broccoli. Greens. Sweet potatoes. Lentils. Flax. Whole grains.

Variety matters.

What About Soy and Breast Cancer?

Few foods have generated more confusion around breast cancer than soy.

The concern usually comes from soy's isoflavones, naturally occurring plant compounds classified as phytoestrogens. Because the word contains "estrogen," people sometimes assume that soy acts like human estrogen and therefore increases breast cancer risk.

That's an oversimplification.

Phytoestrogens interact with estrogen receptors differently than the estrogen produced by our bodies. Population studies have generally not found that traditional soy foods increase breast cancer risk, and soy foods can be part of a healthy dietary pattern.

That means foods such as tofu, tempeh, edamame, and unsweetened soy milk don't need to be feared simply because someone is concerned about breast cancer.

For many people, they're an excellent way to replace foods higher in saturated fat while adding protein, fiber, and other nutrients to the diet.

Alcohol: One Risk Factor Worth Knowing About

Alcohol deserves special attention because the relationship between alcohol consumption and breast cancer risk is well established.

Alcohol can affect estrogen levels and can also be metabolized into acetaldehyde, a compound capable of damaging DNA.

And importantly, breast cancer risk doesn't suddenly appear only with heavy drinking. Risk generally increases as alcohol consumption increases, and even relatively low levels of intake have been associated with increased breast cancer risk.

That doesn't mean we need to approach the subject with fear or judgment.

It means women deserve to know the evidence so they can make informed choices.

If you're looking for an easy swap, try sparkling water with citrus, berries, mint, or another favorite fruit when you would normally reach for a glass of wine.

Movement Is Medicine, Too

Dr. Funk's prevention message doesn't stop at the kitchen.

Regular physical activity is consistently associated with a lower risk of breast cancer.

And you don't need to become a marathon runner.

Brisk walking, cycling, swimming, strength training, pickleball, dancing, gardening — it all counts.

Exercise can influence insulin sensitivity, inflammation, immune function, hormone regulation, and body composition. It can also help reduce weight gain as we age, another important consideration because excess body fat after menopause is associated with increased breast cancer risk.

A useful goal is to stop thinking about exercise only as something we do to burn calories.

Movement sends signals throughout the body.

Every walk is doing more than moving your legs.

Why Body Weight Matters — Especially After Menopause

This is another subject that deserves nuance rather than judgment.

Fat tissue isn't simply passive energy storage. It is biologically active tissue.

After menopause, when the ovaries produce much less estrogen, adipose tissue becomes an important source of estrogen production. Higher levels of body fat can therefore contribute to a hormonal environment associated with greater risk for certain breast cancers.

This doesn't mean thin equals healthy or that weight determines whether someone develops cancer.

It means that maintaining a healthy body composition through nutritious food, regular movement, sleep, and sustainable habits is one of several modifiable factors worth considering as part of an overall prevention strategy.

Rethinking Dairy Without Looking for a Single Villain

Nutrition conversations can quickly become overly focused on individual foods.

Dr. Funk challenged the audience to think critically about dairy and encouraged replacing it with plant alternatives.

But the broader lesson may be even more useful: look at what happens to your overall dietary pattern when you make the swap.

Replacing cheese, cream, and other high-saturated-fat foods with beans, hummus, tofu, whole grains, nuts, seeds, vegetables, and minimally processed plant alternatives can dramatically change the nutritional profile of a meal.

You're not simply removing something.

You're creating room for more plants.

And that's a much more productive way to think about dietary change.

Progress Beats Perfection

Perhaps the most important lesson is that cancer prevention doesn't require a perfect diet.

One meal doesn't determine your future.

Neither does one workout, one vacation, one dessert, or one stressful week.

Our patterns matter.

Add beans to tonight's dinner.

Put berries and oats on tomorrow's breakfast.

Choose a whole grain instead of a refined one.

Take a 30-minute walk.

Try tofu instead of cheese.

Fill half your plate with vegetables.

Each choice may seem small in isolation, but repeated day after day, those choices become your lifestyle.

And that's where their power lies.

Five Things You Can Start Today

If all of this feels like a lot, Dr. Funk's message can be translated into a remarkably practical starting point:

Fill your plate with plants. Center meals around vegetables, fruits, beans, lentils, intact whole grains, and other minimally processed plant foods. 

Prioritize fiber. Work toward getting fiber from food throughout the day rather than trying to make up the difference with a supplement.

Move every day. Walking counts. So does dancing, gardening, cycling, strength training, and anything else that gets you moving.

Know the relationship between alcohol and breast cancer. You can then decide what role, if any, you want alcohol to have in your life.

Think patterns, not perfection. The goal isn't to eat one "cancer-fighting" food. It's to create a lifestyle that supports your health consistently.

Why We Gather

At Plant Strong, we believe knowledge becomes most powerful when people know how to put it into practice.

That's why we gather experts like Dr. Kristi Funk at events like Plant Stock and our immersive retreats — not simply to tell people to "eat healthier," but to help make the science understandable and the next step achievable.

Because knowing that fiber matters is one thing.

Knowing how to build a breakfast with oats, berries, flax, and whole grains is another.

Knowing that eating more plants is associated with better health is one thing.

Learning how to stock your pantry, read labels, cook satisfying meals, and make those choices work in real life is another.

That's where change happens.

The encouraging message from Dr. Funk's talk wasn't that we can control everything about our health.

It's that there are things we can influence.

We can move our bodies.

We can limit alcohol.

We can eat more fiber.

We can fill our plates with an incredible diversity of whole plant foods.

And we can begin with the very next meal.

Every Plant Strong choice is an opportunity to invest in the health of your future self.