People often focus on choosing nutrient-dense foods, leaning toward plant-based options, and cutting back on red meat and sugary processed items. Research over decades has tied these habits to stronger heart health and reduced chances of developing cancer. Yet the benefits of good food choices can be undermined by how those foods are prepared. Certain techniques alter the food’s chemistry in ways that introduce risks many overlook.
The preparation method oncologists most often flag is allowing food to become heavily charred or blackened. When meat, poultry, fish, or even vegetables reach that deep-carbonized stage, harmful compounds form. Heterocyclic amines (HCA) appear when proteins meet extreme heat, while polycyclic aromatic hydrocarbons (PAH) arise when fat drips onto a flame or hot surface and smoke coats the food. Both types of compounds have been linked to DNA damage that may raise the likelihood of certain cancers, especially colorectal cancer.
Dr. Anton Bilchik, a surgical oncologist and director of the gastrointestinal-hepatobiliary program at Providence Saint John’s Cancer Institute, explains the concern clearly. “When food is heavily charred to the point of carbonization, heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH) can form. These compounds can damage DNA in cells and increase the risk of some cancers, especially colorectal cancer,” he notes. The warning applies whether the food is animal protein or plant-based, since high heat and charring trigger the same chemical reactions.
Dr. Shikha Jain, an oncologist and hematologist at the University of Illinois Cancer Center, emphasizes that everyday cooking choices matter over time. “The way food is prepared can change its chemical composition,” she says. “Some cooking methods create harmful compounds, while others better preserve nutrients and can reduce inflammatory processes.” She adds that small differences accumulate and can influence long-term health outcomes, including cancer risk.
Practical advice from the experts is straightforward. If a piece of food develops minor black spots, simply cut or scrape them away. When large portions are deeply burned, it is safer to discard the item, as those areas hold the highest concentrations of HCA and PAH. Dr. Andre Goy of Hackensack Meridian John Theurer Cancer Center recommends choosing gentler preparation techniques to retain nutrients while limiting exposure to these byproducts.
Occasional charring is unlikely to cause major harm on its own. The greater concern arises when heavily blackened food becomes a regular habit. Dr. Jain points out that no precise threshold exists for when risk becomes significant. Frequency and duration of exposure appear to drive the potential impact more than any single meal.
Heterocyclic amines and polycyclic aromatic hydrocarbons have been studied for decades. The International Agency for Research on Cancer classifies several HCA and PAH compounds as possible or probable human carcinogens based on animal studies and limited human evidence. Formation is most pronounced above 300 degrees Fahrenheit, especially with direct flame or prolonged high-heat contact. Grilling, broiling, and pan-frying at very high temperatures are common scenarios where these substances appear in notable amounts.
Safer everyday approaches include steaming, poaching, baking at moderate temperatures, or using slower cooking methods that avoid open flames and excessive browning. Marinating meat beforehand and flipping it frequently on the grill can also lower compound formation. Turning vegetables before they blacken preserves both flavor and safety.
Awareness of these details allows people to enjoy varied meals without unnecessary worry. Simple adjustments in the kitchen can complement healthy food selections and support long-term wellness.
What changes have you made to reduce charring in your cooking, and have you noticed differences in flavor or health? Share your experiences in the comments.
