Dr. Sanjay Gupta: If you limit your sugar you decrease your chances of developing cancer?

Lewis Cantley, PhD: Absolutely.

Cantley, a Harvard professor and the head of the Beth Israel Deaconess Cancer Center, says when we eat or drink sugar, it causes a sudden spike in the hormone insulin, which can serve as a catalyst to fuel certain types of cancers.

Lewis Cantley: What we’re beginning to learn is that insulin can cause adverse effects in the various tissues. And of particular concern is cancer.

Why? Nearly a third of some common cancers—including breast and colon cancers—have something called insulin receptors on their surface. Insulin binds to these receptors and signals the tumor to start consuming glucose [which allows it to grow].

Lewis Cantley: Every cell in our body needs glucose to survive. But the trouble is, these cancer cells also use it to grow. So if you happen to have the tumor that has insulin receptors on it then it will get stimulated to take up the glucose that’s in the bloodstream rather than go into fat or muscle, the glucose goes into the tumor. And the tumor uses it to grow.

Lewis Cantley’s research team is working on developing drugs that will cut off the glucose supply to cancer cells and keep them from growing. But until there’s a breakthrough, Cantley’s advice? Don’t eat sugar. And if you must, keep it to a minimum.

Cantley, a Harvard professor and the head of the Beth Israel Deaconess Cancer Center, says when we eat or drink sugar, it causes a sudden spike in the hormone insulin, which can serve as a catalyst to fuel certain types of cancers.

Lewis Cantley: What we’re beginning to learn is that insulin can cause adverse effects in the various tissues. And of particular concern is cancer.

Why? Nearly a third of some common cancers—including breast and colon cancers—have something called insulin receptors on their surface. Insulin binds to these receptors and signals the tumor to start consuming glucose [which allows it to grow].

Lewis Cantley: Every cell in our body needs glucose to survive. But the trouble is, these cancer cells also use it to grow. So if you happen to have the tumor that has insulin receptors on it then it will get stimulated to take up the glucose that’s in the bloodstream rather than go into fat or muscle, the glucose goes into the tumor. And the tumor uses it to grow.

“Annual mammography to detect breast cancer is a needless expense and pain with no effect on all-cause mortality rates,” writes Joel M. Kauffman, PhD, the author of Malignant Medical Myths: Why Medical Treatment Causes 200,000 Deaths in the USA each Year, and How to Protect Yourself.

In this video clip, Joan Mathews Larson, PhD notes when she started giving patients an iodine/iodide supplement, patients lost weight, had reductions in appetite, and woke up with more energy.

“They couldn’t be happier,” she notes.

Iodine is necessary to make thyroid hormone and protects against breast cancer as noted in this video clip of Joan Mathews Larson, PhD.

Breast cancer is 8 percent more common in the one-fifth of people eating a diet with the highest glycemic index or highest glycemic load compared to the one-fifth eating a diet with the lowest glycemic index / glycemic load according to a study from the University of Sydney in Sydney, Australia.

A woman with a body mass index (BMI) of 20—low normal—has a 7 percent lower risk of breast cancer than a woman with a BMI of 25—high normal—according to a study from the World Cancer Research Fund as reported by the British newspaper the Telegraph.

Among overweight postmenopausal women, the one-forth eating the lowest glycemic index diet were 26 percent less likely to get breast cancer than the one-forth of women eating the highest glycemic index diet according to a study from France. To say this in reverse, the risk of breast cancer was 35 percent higher in the one-forth of women eating the highest glycemic index diet.

A difference of about 60 pounds increases the risk of breast cancer 1.4-fold in postmenopausal women according to a study from the University of Oxford in Oxford, England. Previous research has found that obesity does not increase the risk of breast cancer prior to menopause, in fact, it protects against it.

Studies of White women have found that being overweight lowers the risk of premenopausal breast cancer, but increases the risk of postmenopausal breast cancer. However, this does not seem to be the case with Black women according to a study from Boston University in Boston, Massachusetts, USA.

Women with type 2 diabetes are at a 20 percent greater risk of breast cancer than women without type 2 diabetes according to an analysis by researchers from Sweden.

Among countries in the European Union, 3.4 percent of all cancers in men and 6.4 percent of all cancer in women are attributable to overweight and obesity according to a paper published in the British Medical Journal.

People who consume the most onions reduce the risk of various cancers by 25-88 percent according to a study from Italy.

Even slightly elevated body mass index (BMI) increases the risk of breast cancer in postmenopausal women according to a new study from the University of Hong Kong.

Elevated fasting blood sugar levels—above 140 mg/dL—increase the risk of cancer death by 29 percent in men and 23 percent in women compared to people with the lowest blood sugar levels—less than 90 mg/dL—according to a study from Korea.

An adult weight gain of 20 pounds doubles a woman’s risk of breast cancer according to the U.S. NIH’s Obesity Guidelines (p. 18).

Gaining more than 33 pounds during pregnancy increases the risk of breast cancer 61 percent compared to women who gain the recommended amount of weight of 24 to 33 pounds according to a new study from Finland.

Previous research found that adult weight gain appears to double the risk of postmenopausal breast cancer. New research finds that adult weight loss reduces the risk of breast cancer after the age of 55 by 50-60 percent.

Fat intake is not associated with breast cancer according to a recent study.

Type II diabetes and chronically elevated levels of insulin are associated with an increased risk of cancers of the colon, breast, pancreas, kidney, and endometrium.

Being overweight or obese may account for 23 percent of female cases of breast cancer in the U.S..

One-third to one-half of postmenopausal breast cancer deaths may be due to excess bodyweight according to a study from the American Cancer Society.

Adult weight gain is more important than body mass index (BMI) at determining the risk of postmenopausal breast cancer according to a study from the American Cancer Society.

Being overweight increases the risk of postmenopausal breast cancer by 30 percent in women, while being obese increases the risk 50 percent.

Avoiding weight gain reduces the risk of developing colon cancer, postmenopausal breast cancer, endometrial cancer, kidney cancer (renal cell carcinoma) and oesophagus cancer (adenocarcinoma).