Another fundamental issue with food combining theory involves its outdated view of how digestion works. Many of its principles originated in the 1920s and 1930s, long before modern understanding ...

Food spends different amounts of time in each section of your digestive system. It might take as little as 15 minutes or up to four hours in your stomach, depending on what you eat.

Megan Rossi, a registered dietitian and nutritionist, said that the more we chew our food, the better off we are. “It really just comes down to digestion," she told HuffPost.

Factors that affect digestion time. 1. Type of food. Carbohydrates: Foods rich in carbohydrates, such as fruits, vegetables, and grains, digest relatively quickly.