Ask A Scientist
How does the body convert all food into glucose?
Asked by: Abigail Wheeler
School: Maine-Endwell Middle School
Teacher: Kevin Wagstaff
Hobbies/Interests: Horseback riding and softball
Career Interest: Medicine
Answer from Jessica Surdey
Instructor, Health and Wellness Studies, Binghamton University
Research area: Stress and Self-Esteem
Interests/hobbies: Exercise and Home Renovation
In order to answer this question, it is important to understand that although all food can be converted into glucose, this is not necessarily optimal or the most efficient use of energy. For us to understand this, let’s take a look at the purpose of nutrients.
The main source of energy for our body is carbohydrates. Carbohydrates are foods that contain sugar and starch such as breads, pasta, rice, vegetables, and fruits. When carbohydrates are digested they are broken down into a type of sugar called glucose. Glucose is very important for us because it gives us the energy that we need to get out of bed every morning, go to school, think, play sports, and be active. Glucose is the primary fuel source for the brain, as well as the red blood cells. The average adult brain requires about 120g of glucose each day to function properly.
Fats are used for insulating the body and protecting the organs. Our bodies are designed to store fatty molecules. Fats can be broken down and used as energy, but they break down a lot slower than carbohydrates. Proteins (meat, chicken, eggs, milk, tofu, beans) are used primarily to build and repair muscles and tissues. For this reason, the body is not looking to use proteins as a source of energy. When we do not eat enough carbohydrates or when we have used our available storage, our body turns to sources such as fats and proteins as an alternative fuel that can be converted into glucose. Proteins and fats can go through a process called gluconeogenesis, which allows foods other than carbohydrates to be converted into glucose. The body has to go through several extra steps to do this conversion, so it is not the most efficient way to fuel the body’s energy needs.