Antioxidants are molecules that prevent or slow the damage to cells caused by free radicals, unstable molecules produced by the body as a response to environmental and other pressures. In How Not to Die, Greger emphasizes the importance of consuming antioxidant-rich foods, particularly fruits and vegetables, to reduce oxidative stress and prevent chronic diseases such as cancer, heart disease, and neurodegenerative disorders. The book highlights how a diet high in antioxidants can enhance overall health by neutralizing free radicals and reducing inflammation.

The dopamine reward system is a neural network in the brain that controls feelings of pleasure and reward. Greger discusses how this system is manipulated by the food industry to create addictive products that are high in sugar and fat, leading to overeating and weight gain. By comparing this to substance abuse, Greger illustrates the profound impact of diet on brain chemistry and behavior, urging readers to be mindful of how processed foods can hijack this natural system and contribute to chronic health issues.

Endothelial function refers to the health of the inner lining of blood vessels, which plays a crucial role in vascular health by regulating blood flow and preventing clotting. In How Not to Die, Greger explains that a diet rich in plant-based foods can improve endothelial function, thereby reducing the risk of heart disease.