For the sake of argument and illustration I will presume that certain articles of ordinary diet, however beneficial in youth, are prejudicial in advanced life, like beans to a horse, whose common ordinary food is hay and corn.

In this quote, William Banting, a pioneer in dietary reform, uses the example of beans for a horse to illustrate his argument about diet in advanced life. He suggests that while certain foods may be beneficial when someone is younger, they may become prejudicial to health in later years. By comparing beans, a food that might be unsuitable for a horse whose diet typically consists of hay and corn, Banting highlights how dietary needs can change with age, requiring adjustments for optimal health.

Banting is making the point that ordinary diet staples that are generally considered healthy in youth might not be ideal for older individuals. His analogy to a horse, which thrives on a specific diet, serves to show that not all foods work equally well for everyone at all stages of life. This reflects his broader philosophy that diet should be personalized and tailored to one's age, health, and lifestyle rather than relying on a one-size-fits-all approach.

The origin of this quote comes from Banting’s own experiences with weight management and his promotion of a low-carb, high-fat diet, which became widely known as the Banting diet. He struggled with weight issues throughout his life and found success in adjusting his diet, ultimately advocating for a more controlled approach to eating. His work laid the groundwork for modern low-carb diets, focusing on the idea that certain foods could be harmful when consumed in excess or at the wrong time in life.

Ultimately, Banting’s quote highlights his belief in the importance of understanding how the body’s dietary needs change with age and condition. His message encourages people to consider that what is beneficial in youth may not necessarily be the best choice later in life, promoting a more thoughtful and adapted approach to eating based on individual health and circumstances.