Does Sugar Cause Cancer?
- a) yes
- b) no
- c) maybe
- d) read on
Answer: (d) read on
I recently met a woman, Melanie, who lives in Philly and works with cancer patients in hospice care. She described one man with stage 4 lung cancer who was determined to survive and still had a fighting spirit. But his friends were bringing him pastries and cookies because he was gaunt and they were trying to “fatten him up”. He was eating them. Melanie felt frustrated and helpless.
Which reminds me of the time, 6 months ago, when a friend of mine was in the hospital, also with stage 4 lung cancer. I went to visit her and the windowsill in her room was lined with boxes and bags of cookies that well-intentioned friends had brought to cheer her up. I blasted the packages with my kale-inator and implored my friend not to eat anything, ever, with added sugar.

I am surrounded by friends with cancer
and I hear about newly diagnosed friends of friends all the time. They are mostly in their 40s and 50s, though some are even younger. They all live in developed countries. I’ve already lost a few—one died of breast cancer in San Francisco when the disease returned 10 years after she originally beat it. Another friend in Copenhagen died of esophageal cancer—diagnosed last summer with a month to live. I’d known him for 30 years. I have friends who are struggling with thyroid, ovarian, breast, lung, and lymphoma cancers right here in Austin. A dear cousin is fighting multiple myeloma in Israel. The list of cases goes on, and on, and on.
Why is this happening?
Well, I am not a doctor or a scientist, but I am an insatiable and unstoppable researcher, and there’s copious research linking cancer-causing substances in our environment to cancer in our bodies. We are exposed to chemicals that are classified as known or possible carcinogens in our laundry room, bathroom, kitchen, the grocery store, restaurants, playgrounds. Everywhere. I know, this is discouraging, and you probably feel overwhelmed and wonder “do I really want to read on?” After all, there’s enough to worry about, life is short, we all face challenges, and dealing with all these pesky chemicals sounds time consuming and exhausting, and maybe expensive, too. But yes, you really do want to read this!
What if you could easily avoid some of the worst offenders?
What if you had the knowledge to make choices that reduced your exposure to these poisons? What if reducing your toxic load reduced your chances of getting sick? What if you had the tools to heal your body from diabetes? From cancer? What if it made the difference between life and death?
I know, it’s hard to change your lifestyle and diet. We’re all complacent and creatures of habit. So I am going to take one simple thing off the table: sugar.
Sugar is sweet and yummy and everyone loves it. It conjures up images of bunnies and candy canes and rainbows. It is also a toxic drug that is more addictive than cocaine. And it is everywhere and almost inescapable.
Sugar 101
What actually is sugar?
- Sugars are carbohydrate molecules made of carbon, hydrogen, and oxygen. There are different types of sugar in our diet.
- Fructose is a simple sugar, found naturally in fruits and honey.
- Sucrose (table sugar) is made up of two sugar molecules: fructose and glucose. It is mostly derived from sugar beets and sugar cane, which are processed and refined to create table sugar. It also occurs naturally in some vegetables like peas and sweet potatoes.
- Glucose is the staple of energy for both plants and animals. It is a necessary fuel for cells in our body. Plants make glucose during photosynthesis. It is present in most fruits and vegetables.
- Excess fructose in your bloodstream attracts blood-sucking vampires. Okay I just threw this in for fun, but I’m only half kidding 😉
- Blood sugar refers to glucose, because that’s the sugar molecule that circulates in our blood. Your body eventually breaks down all carbs into glucose.
- Natural raw sugars like honey and maple syrup are preferable to refined sugars such as crystallized white sugar because they retain their original nutrients.
- All simple sugars are absorbed rapidly into the bloodstream, raising blood sugar.
- Your pancreas secretes a hormone called insulin to manage the glucose in your body and deliver it to all your cells.

After the body has satisfied its initial energy requirements from sugar intake…
- sugar is converted into a substance called glycogen and stored in muscle tissue and the liver for available energy use. The glycogen in your liver is then converted to glucose which travels to other tissues that need it, like your brain.
- sugar can be used to help create amino acids, the building blocks of the body.
- sugar can also be used by the body to create fatty acids for long term storage in fat tissue.
This all sounds great. So we need sugar! What’s not to love?
Excess sugar will kick your butt in every possible way
How?

Sugar causes cavities
Yeah, we all know that. This form of damage is really obvious, because your dentist tells you all the time and you can actually see it. When the sugar you eat mixes with plaque, it creates an acid that can cause tooth decay. Unfortunately, many dentists tell you to simply brush instead of reducing sugar intake.
Sugar creates inflammation
Excess sugar creates an acidic environment in your body and weakens your immune system, compromising the ability of white blood cells to fight bacteria and germs. According to French physician and neuroscientist David Sevran-Schreiber, sugar creates inflammation in the body which is favorable to cancer growth. Inflammation is the precursor to physiological imbalances and disease and this provides fertile ground for cancer to grow and spread in our bodies.

Sugar causes obesity
According to the World Health Organization, worldwide obesity has nearly tripled since 1975. By 2016, 41 million children under the age of 5 were overweight or obese. Robert Lustig, Professor of Pediatrics at the University of California at San Francisco, sees obese 6-month olds in his practice. This challenges the belief that weight gain is simply about caloric intake and suggests that there are other factors at play.
Lustig’s research shows that different sugars go through different chemical processes in our bodies—some are metabolized by all cells, while others are metabolized in the liver first, then stored as fat or converted to glucose for immediate use by the body for energy. Could sugar be causing the accumulation of fat? What if certain sugars turn off the signal—your “satiety hormone”—that your body sends to your brain when you are full? Would you believe that excess fructose—the kind that’s added to soft drinks—makes you hungrier and increases sugar cravings? When the brain no longer hears the message to stop eating, it’s because of Leptin resistance, so you keep scarfing down more food. See Dr. Lustig’s argument unfold in The Bitter Truth.

Sugar causes metabolic syndrome
An influx of fructose overwhelms the liver—the organ which metabolizes this simple carbohydrate—and signals it to convert the sugar to fat. Excess fructose entering the liver eventually leads to insulin resistance and progresses to include the related conditions of obesity, heart disease, high triglycerides, high blood pressure and chronic inflammation, which are all metabolic disorders. The dysfunction of all of these regulatory systems leads to metabolic syndrome, which is a precursor to diabetes. It also increases the risk for heart attacks.
Sugar raises blood levels of triglycerides
, which are a type of fat circulating in your blood. When you eat, your body converts any calories it doesn’t need to use right away into triglycerides. The triglycerides are stored in your fat cells. Researchers at Yale and Rockefeller reported back in the 1960s that these two lipids had been confused—that triglycerides, and not cholesterol, correlated with heart disease. Yet the myth that eating cholesterol causes heart disease has persisted. Read what the Mayo Clinic has to say about triglycerides.

Sugar raises insulin levels
which leads to type 2 diabetes. Insulin is secreted by your pancreas to manage rising blood sugar after the consumption of carbs. Simple sugars cause the greatest spike in blood sugar. If insulin has to come to the rescue over and over again, the body eventually becomes insulin resistant. Unlike glucose, fructose doesn’t raise insulin levels. But it still contributes to insulin resistance and diabetes. When too much insulin is secreted it causes lipogenesis, or fat formation. And sugar intake is associated with diabetes even if you’re not obese.
Diabetes was first discovered about two thousand years ago in “gluttonous and corpulent” people but continued to be rare until the 19th century. Its incidence started to soar after the industrial revolutions in the U.S. and England which launched the candy, cereal, and soft-drink industries. Sugar consumption skyrocketed in the early 20th century. Then, it declined because of shortages during WWII, and these shortages resulted in fewer diabetes deaths.

The 1970s brought a “low-fat” dieting craze in which fat was skimmed off everything and sugar poured into everything. Bacon and eggs left the breakfast table and were replaced by sugary cereals with skim milk. Consumption of sugars—especially fructose—has increased every year since. By 2017, millions of adults— one of every 11 Americans—had been diagnosed with diabetes.

People with diabetes have a much greater risk of heart disease, stroke, and kidney disease, not to mention failing eyesight and hearing, nerve damage, even gangrene, and amputated limbs. You definitely do not want diabetes. If you already have it, you want to do everything possible to reverse it—because yes, it’s a diet-related disease.
Sugar causes fatty liver disease
Fructose can cause excess fat to build up in your liver, damaging it and causing non-alcoholic fatty liver disease (NAFLD). 31% of American adults and 13% of kids currently suffer from non-alcoholic fatty liver disease. This condition can lead to insulin resistance and metabolic syndrome. It can also cause scarring, cirrhosis, or needing a liver transplant. Give me my liver back! Find out the toxic truth from a team of investigators at the University of California, San Francisco.

Sugar is linked to cardiovascular disease
According to Laura Schmidt, Phd, UCSF investigator on the link between sugar and disease, “There is now a considerable body of evidence linking added sugars to hypertension and cardiovascular disease, which is the No. 1 cause of premature death in the developed world.”
This study in the Journal for the American Medical Association (JAMA) correlated glycemic load to risk of cardiovascular disease. What’s glycemic load? It is a number that estimates how much a particular food will raise a person’s blood glucose level after eating it. Another study found that a high percentage of calories from added sugar—and especially sugary drinks— significantly increased mortality from cardiovascular disease.
This study correlated glycemic load to risk of cardiovascular disease. Many studies corroborate this finding.
Sugar is linked to cancer
One of the diseases that has increased alongside obesity, diabetes, and metabolic syndrome is cancer. So it is likely that insulin resistance creates a hospitable environment to cancer, as it does for type 2 diabetes and heart disease. The connection between obesity and cancer is clear based on 15 years of research by the World Health Organization’s International Agency for Research on Cancer. A 2016 study found significant associations between body mass index (BMI) and cancer risk for the colon, rectum, gastric cardia, liver, gallbladder, pancreas, and kidney and for esophageal adenocarcinoma. Conversely, the absence of excess body fat was found to lower the risk of most cancers. It appears that people are more likely to get cancer if they are obese or if they have metabolic syndrome. Another report from 2017 establishes a clear link.
According to David Sevran-Schreiber, a physician and neuroscientist who founded the American branch of Doctors without Borders, sugar is the #1 cancer promoter in the West. He believes that sugar feeds cancer directly—that cancer cannot feed on anything besides raw sugar. In fact, cancer is detected in the body through a PET scan which measures the presence of radioactive sugar in the body.

Dr. Joseph Mercola, who writes one of the internet’s most comprehensive health blogs, explains how fructose elevates blood pressure and triglycerides, depletes vitamins and minerals; raises insulin resistance and leads to obesity and cardiovascular disease, liver disease, cancer, arthritis, and even gout. And this is not from the small amount of naturally occurring fructose in fruit, it’s from the large amounts of added fructose in your soft drinks and packaged foods.
We know that insulin resistance causes the pancreas to secrete more insulin. This insulin in conjunction with a hormone called insulin-like growth factor (IGF) appears to promote tumor growth. This study from the National Institutes of Health shows a synergistic relationship between obesity-related insulin resistance and/or diabetes and cancer. According to the Society for Endocrinology, the link between obesity, diabetes, and cancer appears to be related to several factors including insulin resistance, increased levels of IGF, and inflammatory markers.
Sugar Kills
According to a recent study by the New Harvard School of Public Health, roughly 180,000 obesity-related deaths worldwide—including 25,000 Americans—are associated with the consumption of sugary drinks. The paper was presented at a scientific conference of the American Heart Association.
Takeaway: Sugar will ruin your health
Sugar basically causes everything to go wrong. As explained by science journalist Gary Taubes, it’s not just a problem of overconsumption, but that sugars have unique physiological, metabolic, and endocrinological effects in the body which trigger disorders. And if you succumb to one of the disorders, you are at high risk for the others because they are all related: people who are obese and diabetic also tend to have hypertension, and they are at greater risk of heart disease, cancer, stroke, and possibly dementia. Another warning: once the body’s regulatory processes start to malfunction, food rich in carbohydrates seem to hasten the decline.
What should I do?
- Don’t drink soda, which contains mountains of sugar (either fructose or sucrose)
- Read labels on everything that comes in a package. Try to avoid added sugar
- Eat dessert sparingly and not every day
- Eat lots of fruits and vegetables. (twice as many veggies as fruits, if you can)
Tune in for the continuation of this article to find out
- when the first government dietary guidelines came out and why they were wrong
- where sugar is hiding (hint: everywhere. But how do you recognize it?)
- If sugar is so toxic then how come it’s not regulated?
- how conflicts of interest lead to a health crisis?
- how we all became addicted to sugar
- how much sugar is okay
- how to raise kids in a sugar culture
- how to wean yourself off sugar
- GFF recommended sugar substitutes, and
- what happens to a non-sugar eating population that is suddenly slammed with sugar
- resources and recommendations: learn more about the history, the politics, and the research on sugar.
Read Does Sugar Cause Cancer Part 2 here.
Fun Fact:
In 1830 we consumed about 15 pounds of sugar each year, largely in a healthier, less processed form called molasses. Today the average American scarfs down 150 pounds, mostly as high fructose corn syrup.
Fun Fact: In 1830 we consumed about 15 pounds of sugar each year, largely in a healthier, less processed form called molasses. Today the average American scarfs down 150 pounds, mostly as high fructose corn syrup. Do you think our bodies have evolved to assimilate all that without going haywire? Check out this cool timeline. Interestingly, a French lawyer and food writer was disseminating highly accurate diet advice in 1825 before the sugar industry took over our minds and appetites.
She left this world much too soon, but lived life to its fullest and coached violin students until the very end. Here she is 6 weeks before her passing dressed up one last time in her favorite clothes and jewelry, posing with her beloved son.

Note: all mentions in article of Diabetes refers to Type 2 Diabetes and not Type 1.
Thank you for your dedication.
That’s very kind of you, Sandra! Thanks for reading the article!
-your GFF
Great job, I have always maintained sugar=poison. Period.
hi Tish, I would just qualify that with “added” sugar, or excess sugar, since fruit sugar is harmless when eaten in it’s natural form in reasonable quantities ;-). I appreciate your comment!
-your GFF
I think I had the idea but to read it all together with the links/footnotes really makes an impact. The old ads are funny… but they are still trying to sell it to us. Thanks GFF!
Hi Jonny,
Always follow the money! I look carefully at where food comes from, who is being subsidized, who funds studies, who evaluates studies, where there are conflicts of interest, etc. It’s a lot of work but it’s fascinating and it makes me happy when it results in people making better food choices.
Power to you!
-your GFF
Thank you so much 💓 for sharing your amazing powering study.