Cancer is a disease where cells in the body grow uncontrollably, forming lumps known as tumors. Research has shown that a variety of factors can cause or contribute to cancer growth. Some are beyond a person’s control, such as a family history or genetic disposition. However, lifestyle habits like dietary choices may also play a role. Choosing healthier foods can help reduce the risk of developing cancer.

Early detection is one of the most important factors that can directly impact survival rates. When detected early through tools such as routine screenings, checkups, and doctor visits, the chances of successful treatment increase. Yet, Black people in the United States often have worse outcomes from cancer. This is due in part to inconsistent medical care, which can result in being diagnosed at later stages when cancers are more aggressive and treatment success is less likely. While food alone can’t completely influence cancer, knowing which foods to avoid or limit can help people safeguard their health.

What does cancer need to thrive?

Cancer is often a slow-developing condition. It usually begins when normal cells experience structural DNA damage. Over time, the damage accumulates. If the body’s repair systems, such as the immune system or even cellular turnover, can’t fix the damage or remove the damaged cells, they grow unchecked. These abnormal cells can become tumors, metastasize (spread), or invade other tissues in the body.

Certain factors can increase the chances of cancer growth, such as:

• Chronic inflammation: Ongoing inflammation can damage DNA, which can encourage cancerous changes in the cells.
• Hormonal factors: Some cancers, like prostate or breast cancer, are influenced by hormones like estrogen or testosterone.
• Toxins and carcinogens: Exposure to harmful chemicals found in food smoke, or the environment can damage DNA and increase cancer risk.
• High blood sugar, obesity: Poorly managed chronic conditions such as diabetes or high blood pressure, which are often found in people struggling with obesity, can fuel abnormal growth.
• Weakened immune system: If the body can’t detect and kill abnormal cells, they may survive and multiply.
• A family history: Individuals with a family history of certain cancers are at a higher risk of developing them themselves. 
• Prior health issues: Sometimes, getting certain illnesses or even being exposed to sustained radiation in work environments can increase a person’s cancer risk. 

What is the number one food linked with cancer?

Cara Anselmo, MS, RDN, CSOWM, CDN, a level III clinical dietitian-nutritionist who specializes in breast cancer nutrition for nutrition programming at the Evelyn H. Lauder Breast Center at Memorial Sloan Kettering Cancer Center in New York, says that moderation is one of the key factors people should prioritize when creating a balanced diet that reduces cancer risk. She continued, “Dietary patterns play a larger role in our health and cancer risk than individual foods.”

While it’s hard to name a single “number one food” that always causes cancer, one of the strongest and most consistent links is processed meats. Minimizing “high-risk” foods should be a priority not just for reducing cancer risk, but also for improving overall health.

Below are several foods or food types that research suggests can increase the risk of cancer. However, “increase the risk” doesn’t guarantee cancer will result.

Processed meats

Processed meats – a category that includes popular items such as bacon, sausages, hot dogs, salami, ham and beef jerky – have been officially classified as “carcinogenic to humans” (Group 1) by the International Agency for Research on Cancer (IARC). This classification places processed meats in the same evidence category as tobacco and asbestos, indicating that there is sufficient scientific proof that they cause cancer in humans.

The health risks arise primarily from the methods used to preserve these meats and enhance their flavor. Techniques such as smoking, curing, salting and the addition of chemical preservatives (like nitrates and nitrites) can lead to the formation of harmful, cancer-causing compounds, including N-nitroso compounds and polycyclic aromatic hydrocarbons.

According to the World Health Organization (WHO), the consumption of processed meat is most strongly linked to an increased risk of colorectal cancer. Furthermore, regular intake has also been associated with other chronic health issues, such as heart disease and type 2 diabetes. Health experts generally recommend limiting the intake of these foods in favor of fresh, unprocessed alternatives like poultry, fish or legumes.

Red meat

Red meat, which encompasses all mammalian muscle meat, including beef, veal, pork, lamb, mutton, horse and goat, is a staple in many diets, yet it carries significant health warnings. The IARC has classified red meat as Group 2A: probably carcinogenic to humans. This classification indicates that there is positive evidence linking red meat consumption to cancer, particularly colorectal cancer. However, other explanations for the association (such as chance or bias) could not be entirely ruled out.

While colorectal cancer presents the strongest link, high intake of red meat has also been associated with malignancies in other parts of the body, including the breast, stomach and liver. The potential risk is often compounded by how the meat is prepared; cooking methods that use high heat, such as pan-frying or grilling, can produce harmful compounds that may contribute to carcinogenic effects.

Furthermore, studies show that the risks extend beyond cancer directly. Excessive consumption is closely tied to metabolic and cardiovascular issues, specifically Type 2 diabetes and high blood pressure. These conditions can create a systemic environment of inflammation and stress within the body, which may act as contributing factors to the development of cancer and other chronic diseases.

Ultra-processed foods

Ultra-processed foods (UPFs) represent a distinct category of industrial food products that go far beyond simple preservation methods like canning or freezing. These foods are essentially industrial formulations made mostly or entirely from substances derived from foods and additives, with little if any intact raw food. They typically contain ingredients rarely found in home kitchens, such as high-fructose corn syrup, hydrogenated oils, protein isolates and chemical additives like emulsifiers and flavor enhancers. Common examples include:

• Sugary soft drinks and energy drinks

• Mass-produced packaged breads and buns

• Reconstituted meat products (like nuggets and fish sticks)

• Instant noodles and soups

• Packaged snacks like chips and cookies

Research has increasingly linked the consumption of these foods to adverse health outcomes, including a heightened risk of cancer. The nutritional profile of UPFs (often calorically dense but nutrient-poor, lacking fiber and essential micronutrients) can contribute to chronic inflammation and obesity, which are well-established drivers of carcinogenesis.

The specific impact on liver health is particularly concerning. According to recent findings, the correlation is significant: one study demonstrated that individuals with a high consumption of ultra-processed foods faced a 1.69 times higher risk of liver cancer compared to those with low consumption.

Sugary drinks

Sugary drinks – often referred to as sugar-sweetened beverages (SSBs) – are a primary source of added calories in the modern diet. This category includes non-diet sodas, sweetened fruit juices, sports drinks, energy drinks and sweetened teas. While the link between sugar and cavities or weight gain is well-known, the potential connection to cancer is a growing area of concern driven by complex biological mechanisms.

Research utilizing laboratory and animal models suggests that excessive sugar consumption can directly fuel chronic inflammation and alter metabolic processes. When you consume liquid sugar, it causes rapid spikes in blood glucose and insulin. High levels of insulin and Insulin-like Growth Factor (IGF-1) can signal cells to divide more rapidly and reduce cell death (apoptosis), essentially creating a fertile environment for cancer cells to thrive.

Alcoholic beverages

Alcohol intake increases the risk of at least seven types of cancer: breast, colon, esophagus, liver, mouth, throat and voice box, according to the National Cancer Institute. Even light drinking raises the risk of breast cancer in women. “In your efforts to potentially minimize your breast cancer risks, there are several factors to consider. Family history, age, nutrition and prophylactic medications,” explains Dr. Diana Rangaves, PharmD, RPH.

Refined grains 

Refined grains are a pervasive part of the modern diet, forming the basis of staples like white bread, white rice, pasta, pizza dough and pastries. Unlike whole grains, refined grains undergo a milling process that removes the two most nutritious parts of the kernel: the bran (the outer fiber-rich layer) and the germ (the nutrient-packed core). This leaves only the endosperm, resulting in a product with a finer texture and a longer shelf life but severely depleted of essential fiber, iron and B vitamins.

Because they lack fiber, refined grains are digested rapidly, meaning it’s not long before you feel hungry again. Research shows that this cycle of rapid digestion and hunger is a primary driver of obesity, which is the central link between refined grains and cancer. Excess body fat creates a state of chronic low-grade inflammation and hormonal imbalance (such as elevated estrogen and insulin), which are known physiological drivers for cancer development.

Hydrogenated oils and trans fats

As noted by the FDA, hydrogenated oils are the primary source of artificial trans fats, created through an industrial process that adds hydrogen to liquid vegetable oils to make them solid at room temperature. This process, often used to extend shelf life and improve the texture of processed foods like margarine, commercial baked goods and fried foods, results in a fat structure that the human body struggles to process.

While the devastation they cause to heart health is well-documented (raising “bad” LDL cholesterol while simultaneously lowering “good” HDL cholesterol), growing evidence points to a sinister link with cancer. The biological mechanism linking trans fats to cancer primarily involves chronic inflammation and oxidative stress. Trans fats can damage the lining of blood vessels and disrupt cellular function, leading to a systemic inflammatory state. This chronic inflammation is a known precursor to neoplastic transformation (the formation of tumors).

Artificial sweeteners 

Artificial sweeteners, such as aspartame, acesulfame-K (Ace-K) and sucralose, are chemically synthesized sugar substitutes used widely in “diet” sodas, sugar-free gum and low-calorie snacks. While they are effective for reducing caloric intake, their safety profile has recently come under intense scientific scrutiny.

The concern gained significant traction when the IARC classified aspartame as “possibly carcinogenic to humans” (Group 2B). This classification was based on “limited evidence” suggesting a potential link to liver cancer (hepatocellular carcinoma).

However, “association” does not prove “causation.” Many health experts argue that these findings are not conclusive because they may be influenced by reverse causality or confounding factors. For example, individuals who consume high amounts of diet sodas may already have higher body weight or metabolic issues, which are independent risk factors for cancer. Consequently, major food safety agencies (like the FDA and EFSA) maintain that these sweeteners are safe for the general population when consumed within the Acceptable Daily Intake (ADI) limits, as shared by the National Library of Medicine.

Bottom line

Dietary choices can directly help people fight against cancer or encourage it. Avoiding or limiting foods like processed meat, ultra-processed products, sugary drinks and heavy alcohol use can reduce risk. But diet is only one piece as lifestyle factors and regular medical screenings matter too. It’s about stacking good choices so cancer has fewer chances.

Frequently Asked Questions

What is the best protein for cancer patients?

The best protein choices include lean poultry, fish, eggs, legumes (beans, lentils, peas), nuts and seeds in moderation, low-fat dairy or plant-based milks and lean cuts of red meat consumed in moderation. Cara Anselmo cautions readers that if undergoing cancer treatments that can make them immunocompromised, they should avoid raw fish like sushi or ceviche and only consume fully cooked animal proteins. 

Which multivitamin is best for cancer patients?

Speak with a physician for recommendations before opting for a multivitamin, as high-dose vitamins or supplements may interfere with treatment or affect cancer cells. Whole foods (fruits, vegetables, grains, and protein) are usually the better first choice for getting the nutrients you need.

Citations

World Health Organization Staff. Cancer: Carcinogenicity of the Consumption of Red Meat and Processed Meat. World Health Organization. October 2015. https://www.who.int/news-room/questions-and-answers/item/cancer-carcinogenicity-of-the-consumption-of-red-meat-and-processed-meat

Qian F, Riddle MC, Wylie-Rosett J, Hu FB. Red and Processed Meats and Health Risks: How Strong is the Evidence? Diabetes Care. January 2020. https://pmc.ncbi.nlm.nih.gov/articles/PMC6971786/

Zhao L, Zhang X, Yu D, et al. Ultra-Processed Products and Risk of Liver Cancer: A Prospective Cohort Study. Clinical Nutrition. October 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11479389/

Epner M, Yang P, Wagner RW, Cohen L. Understanding the Link Between Sugar and Cancer: An Examination of the Preclinical and Clinical Evidence. Cancers. December 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9775518/

National Cancer Institute Staff. Alcohol and Cancer Risk Fact Sheet. National Cancer Institute. July 2021. https://www.cancer.gov/about-cancer/causes-prevention/risk/alcohol/alcohol-fact-sheet

Sivasubramanian BP, Dave M, Panchal V, et al. Comprehensive Review of Red Meat Consumption and the Risk of Cancer. Cureus. September 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC10577092/

Chang K, Gunter MJ, Rauber F, et al. Ultra-Processed Food Consumption, Cancer Risk and Cancer Mortality: A Large-Scale Prospective Analysis Within the UK Biobank. eClinicalMedicine. January 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC9985039/