Does sugar feed cancer?

It is a common myth in the cancer community that consuming sugar through your diet will feed cancer cells in the body.  Though the origination of this myth is unknown, it is partially thought to be due to how PET scans function.  PET scans are a type of scan used to look at where cancer is in the body.  In order to do a PET scan, the patient is injected with a radioactive glucose tracer, which is then taken up by all cells in the body.  The cells that are the most metabolically active – or require the most energy – will take up more of this tracer and this part of the body will “glow” on the scan.  This “glowing” on the scan represents cancer cells.

However, as previously mentioned, EVERY CELL IN THE BODY uses glucose (sugar) for energy, whether we’re talking about our normal, healthy cells or cancer cells.  Some people think that if they cut back on the dietary sugar/carbohydrates they consume, it will help starve the cancer cells.  This is mistaken, though, since it also decreases the glucose energy available to our healthy cells.  Our bodies are extremely resilient and since it needs glucose for energy to function, it will begin to break down muscle and fat stores to provide this glucose if we don’t consume enough through our diets.  

With that being said, it is still important to limit simple sugars you eat like pop, juice, baked goods, chocolate, other sweets, white breads, white pastas, and refined cereals like rice krispies and many kids’ cereals.  Any time we consume carbohydrates, it causes insulin to be released in our bodies.  Insulin is a storage hormone that essentially works as part of a lock and key system.  Insulin can be thought of as being the key, and a cell in the body can be thought of as having a lock on it.  When carbohydrates are eaten, insulin is released and “unlocks” the cells to allow the sugars from the carbs enter the cell to provide energy.  
The problem is, insulin functions as a growth hormone and can potentially cause growth of tumor cells.  When people are diagnosed with type 2 diabetes or insulin resistance, it means their body’s cells resist allowing insulin “unlock” the cell, so the body has to pump out even more insulin than normal for the cell to finally be “unlocked”.  Being overweight or obese is a risk factor for insulin resistance, which is why many cancers such as colorectal, endometrial, and pancreatic are associated with carrying excess body weight.   

We’ve already determined that our bodies need us to consume carbohydrates in our diets for energy, and if we don’t consume enough, our bodies will break down our muscle and fat tissues to provide it.  However, whenever we eat carbs, it causes insulin to be released, which we know can promote cancer growth.  What do we do?  

The best thing you can do is focus on making healthy carbohydrate choices, such as from whole grains, fruits, and vegetables.  These types of foods innately have many anti-cancer properties to them because of their high phytochemical content, and they also have the added benefit of the fiber they contain will slow down digestion and reduce the amount of insulin released.  While fiber can slow down gut transit time, protein and fats in the diet also carry the same function.  Therefore, every time you’re eating – whether it’s at mealtime or snack time – make sure you have included some sort of fiber, protein, or fat in your food choices.  For example, instead of having plain club crackers for a snack, choose a whole wheat cracker and/or top the cracker with peanut butter or a little bit of cheese.  If you like to snack on chocolates, mix chocolate chips into a trail mix with some nuts and dried fruits.  Pairing your foods can be an often overlooked but smart way to snack.  

To summarize, dietary sugar/carbohydrates do not “feed” the cancer cells any differently than it feeds our normal, healthy cells, so it’s not possible to starve the tumor through restricting carb intake.  Since we need carbohydrates to function, choose wisely and incorporate a variety of fruits, vegetables, and whole grains into your diet.  Whenever you eat a meal or snack, also work to incorporate some sources of fiber, protein, or fat to slow digestion and reduce the body’s insulin release.  

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