From the smallest cell to the largest organism, when a segment of life is no longer filling its role as part of a healthy collective, it is cancerous. Cancer in a body occurs when cells become diseased, feed on wasteful metabolic processes, procreate, and refuse to die according to the normal schedule. When cancer overtakes the body, without intervention and radical changes, that organism will likely die.

Sugar is a concentrated representative of the sweetness of life, delightful in small amounts but dangerous if enjoyed to excess. Back in the day sugar was a rare treat in which we could occasionally indulge, but now it is ubiquitous and seemingly inescapable. Sugar is added to nearly every processed food modern humans eat, and forms the foundation of the standard contemporary diet. Most of the world is addicted to the quick burst of energy and rush of pleasure that sugar provides, without always being aware of the potentially harmful side effects. At the same time, cancer rates are at an all-time high, with people of all ages and backgrounds all over the world suffering and dying from this cell mutation. Is it our addiction to sweetness that is causing so many lives to turn sour?

What Does Sugar Do To The Body?

First lets define what we mean by sugar. Chemically, sugar refers to the simple carbohydrate compounds monosaccharides and disaccharides. These include glucose, fructose, lactose, maltose, and sucrose. To keep track, it is helpful to know that if something ends in -ose or -ol it is a form sugar. All food we eat is eventually broken down into glucose, which is the primary fuel for every cell in our body. More complex food cells take more time to break down into glucose, and usually provide more nourishment and fuel.

Eating purely glucose or other simple carbohydrates causes blood sugar levels to spike and fall rapidly, triggering a whole host of reactions in the pancreas, liver, stomach, and brain. Insulin, adrenaline, and cortisol are released to manage the blood sugar levels, first trying to use and absorb the glucose into fat cells, then triggering the desire for more glucose when the first surge of sugar has been stored. It is ultimately quite stressful for the entire body. This is how a person can drink an entire can of soda and follow it up with a piece of cake, and then feel hungry and cranky half an hour later, having gained weight in the process but without actually nourishing the body. Eating food with lower glucose content and higher amounts of other nutrients like fat and protein is generally less stressful for the body, as they are broken down more slowly and do not produce the same hormonal reactions.

The Known Sugar-Cancer Connection

What doctors and hospitals are willing to admit is that eating too much sugar and other processed food can lead to weight gain, insulin resistance, and metabolic syndrome. Study after study has shown that obesity is a leading cause of cancer, and people who are overweight have a significantly higher risk of developing it. There has been enough scientific and anecdotal evidence for this connection to become irrefutable. Even the American Cancer Society, known to be conservative about its dietary and alternative health recommendations, states that there is a connection between obesity and cancer development.

What most well-known health professionals highlight is the link between an overall unhealthy lifestyle and the development or worsening of cancer. It is the combination of eating an excess of simple carbohydrates with a sedentary lifestyle that leads to insulin resistance, which is understood as a primary factor in developing cancer. Health professionals tend to agree that limiting excess carbohydrates, especially those with a high glycemic index, and exercising regularly are important for preventing and treating cancer.

Sugar As A Primary Cause of Cancer?

This is where the argument becomes a bit more hazy. Most mainstream health organizations such as the Mayo Clinic are unwilling to admit a direct link between sugar and cancer formation. But evidence is surfacing that cancer initiation is driven by sugar-based metabolism. It has already been evident for some time that tumors feed on sugar fermentation rather than the oxygen-based processes that give energy to healthy cells and produce less cellular waste. But recent studies indicate that an overabundance of sugar can stimulate mutation in healthy cells as the body is decreasingly able to burn or sequester excess glucose. After a certain threshold, cells can develop more glucose receptors on their membranes. The increased presence of glucose in a cell combined with increased numbers of glucose receptors on the cells surface can turn a cell cancerous. It seems that too much sugar can cause a cell to mutate into a diseased, immortal, self-propagating state.

Part of what makes cancer so powerful is this mutation in glucose processing. Healthy cells feed on a combination of glucose and oxygen, which is called aerobic oxidation of glucose. It is a fairly efficient process that produces a lot of energy with minimal cellular waste. Cancer cells, however, feed on glucose devoid of oxygen anaerobic glycolysis which extracts only about 5 percent of the energy available in food and creates a significant amount of waste. Part of this waste is lactic acid, which the liver than processes back into glucose, feeding the cancer cells again. This is one of the ways cancer becomes immortal, producing the food it needs to survive while wasting energy and creating more acidity in the body, depriving the rest of the body of energy for vital processes. Forty percent of cancer patients technically die from malnutrition, regardless of what food or supplements they eat, because their cells are not getting enough energy. Taking in more dietary glucose, in the form of any simple carbohydrate, just worsens that problem.

The upside is that some studies are revealing that interfering with the availability of sugar to cancer cells and removing simple carbohydrates from the diet can halt the spread of cancer, and even cause some types of cancer cells to revert to a pre-cancerous state. Healthy cells can be fueled by fat and protein, but cancer cells can only eat sugar. They can produce a small amount of glucose themselves through the liver-lactic acid process mentioned earlier to survive, but removing excess sugar from the diet can keep them from propagating as quickly.

Whether sugar is directly causal in cancer cases or not is still a question of debate that requires more research. But what is clear is that people with chronically high blood glucose levels are more likely to develop cancer, through either contributing factors like obesity and insulin resistance or directly from sugar-induced cellular mutation, and people with cancer who maintain high blood glucose levels tend to have the lowest survival and recovery rates.

All That Sweetens Is Not (Called) Sugar

It seems clear that limiting sugar intake is a wise move to prevent the development of cancer, directly or indirectly. To facilitate that, it is important to know all the places that sugar hides in our food. The most important foods to avoid are the ones that list sugar as one of the first ingredients. When it is just called sugar, that is easy enough. But sugar has many names, and it is important to check for them all if you choose to eat packaged foods:

  • fructose
  • corn syrup
  • high fructose corn syrup (HFCS)
  • dextrose
  • maltose
  • lactose
  • sucralose
  • galactose
  • maltose
  • fruit juice concentrates
  • evaporated cane juice
  • cane juice crystals
  • caramel
  • corn sweetener
  • sorbitol
  • ethyl maltol
  • diatase
  • crystalline fructose
  • demara sugar
  • diastatic malt
  • maltodextrin
  • mannitol
  • barley malt
  • beet sugar
  • blackstrap molasses
  • turbinado sugar
  • brown rice syrup
  • agave syrup

And then there are the many simple processed carbohydrates that might be sweet or savory, but act like sugar in your bloodstream: white bread, pastries, crackers, chips, white rice, pasta, cake, cookies, other baked goods, cereals basically anything made with wheat, corn, rice, or other types of flour.

It is also important to avoid artificial sweeteners such as Splenda and aspartame, which have been linked to cancer in preliminary studies.

How Much Sugar Is Safe?

A healthy life includes moderation. This article is not intended to make you think that if you have a little sugar on occasion you are on the fast-track to cancer. What matters is limiting the amount of simple carbohydrates you ingest to manageable levels, within a context of a diet that includes plenty of vegetables (complex carbs) and protein.

According to the American Heart Association, women should stick to less than 25 grams of sugar (which includes all kinds of processed simple carbs) per day, and men should have less than 37 grams. To manage blood sugar levels, having small frequent meals is advised, as is having complex carbs and protein shortly after eating sugar to pause the craving cycle.

Sugar That Can Truly Nourish

It is important to note that there is a distinction between processed sugar even natural ones like agave syrup and whole foods that contain some naturally occurring sugar. Eating a piece of intact fruit with all its fiber and phytonutrients is usually healthy for the body. Many fruits contain anti-oxidants that actually help protect the body from the development of cancer. Enjoying moderate amounts of whole fresh fruit (not dried or juiced) can satisfy the desire for something sweet in a way that is healthy for the body, in the context of a diet that is based on primarily vegetables.

Life After Sugar

Of course, sugar is highly addictive, so getting off it is easier said than done. Eating sugar sets off a chain-reaction of craving that can overrun our best intentions. Like any other type of addiction, it takes many small choices to find the way to health. Choose an apple over a candy bar, or a baked yam over a slice of cake. Start preparing your own veggie-rich meals as much as possible, slowly but surely adapting your body to the mellower pace of balanced blood sugar levels.

Cancer is a complex disease with a variety of factors, many of them beyond our control. But what we can control is what we choose to eat. The full extent of the link between sugar and cancer is still being discovered. But so far the evidence indicates that limiting our intake of simple carbohydrates is important for protecting and preserving our health.


MD Anderson Cancer Center
Green Med Info
Dana Farber Cancer Institute
Oncology Nutrition
Patrick Quillin, PHD