Why People Thought Sugar Feeds Cancer
For nearly a century, researchers have observed that many types of cancer cells take up glucose at a much higher rate than normal cells. This is known as the Warburg effect. Because cancer cells seem to consume more glucose, some people believed that eating less sugar or carbohydrates could starve the cancer. That belief led to extreme recommendations that even healthy carbohydrate sources like fruit or starchy vegetables should be avoided.
Why That Belief Is Misleading
Healthy cells throughout the body also rely on glucose for fuel. The brain, muscles, and immune system all need carbohydrates to function properly. If you remove all carbohydrates from the diet, cancer cells will not simply die. Instead, they can switch to other fuel sources like amino acids from protein or fats. The body may also become weaker if it does not receive enough fuel from healthy carbohydrates.
Avoiding all carbs in an effort to starve cancer often ends up starving healthy tissue. It weakens immune function, reduces energy levels, and can even impair healing.
Protein and Cancer Growth
Some people think that replacing carbs with protein is a safer option, but that may not be true. Certain cancer cells can use amino acids as fuel. Too much protein may help cancer grow rather than stop it. When protein is consumed, it bypasses the energy pathway known as the Krebs cycle and is broken down into amino acids, which can be used in various ways, including as energy for fast-growing cells.
How Carbohydrates Work in the Body
Carbohydrates are digested into glucose, which enters the bloodstream and gets absorbed by cells through a regulated process. The glucose goes through the Krebs cycle inside the mitochondria to create usable energy in the form of ATP. This process also supports healthy cell function, repair, and communication. Without carbohydrates, the body struggles to produce energy efficiently and must break down fat or protein for alternative fuel.
What Modern Nutrition Science Says
Today, science-based diets do not restrict all sugars and carbs. Instead, they focus on limiting refined and processed sugars while encouraging healthy carbohydrates from whole foods. Whole fruits, vegetables, beans, and whole grains contain not only natural sugars but also fiber, vitamins, minerals, and antioxidants that support healing.
The right amount of carbohydrates depends on a person’s lifestyle, metabolism, and level of physical activity. In most cases, eating a moderate amount of healthy carbs is part of a well-balanced diet that supports overall well-being and long-term health.