This question of sugar – especially as it relates to cancer – has become a dominating topic of conversation in the world of nutritional science and public health. No one is lighting the fuse more fiercely than Robert Lustig, a pediatric endocrinologist who has emerged as one of the most outspoken critics of sugar consumption and who also advocates dietary approaches to cancer care.

Sugar and Metabolic Dysfunction

He argues that although humans have some resistance to the effects of fructose, especially to metabolic diseases, when fructose is consumed in quantity, it plays a key role in the development of these diseases. Here’s how Dr Lustig explains it: Because most of the fructose from added sugars, like sucrose, goes to the liver –your metabolic filter – it directly causes insulin resistance. You cannot get type 2 diabetes without insulin resistance.

You cannot get heart disease without insulin resistance…, and you cannot get cancer without insulin resistance. That is why insulin resistance is the common thread of all chronic diseases. The pancreas compensates for this by making even more insulin, and as we saw with cancer, elevated insulin levels can be used by cancer cells to promote their growth.

Treating Cancer Patients: A Metabolic Approach

In an oncology context, Lustig might encourage a cancer patient to focus on controlling insulin levels through dietary management so that by reducing sugar intake, insulin resistance would decrease. While not a treatment on its own, lowering circulating insulin, which is one of the growth factors for cancer, could potentially raise the chances of a patient’s cancer becoming less aggressive and easier to treat. A diet lower in added sugars and higher in fiber could help the patient maintain stable blood glucose and insulin levels.

The Role of Inflammation

Lustig notes that sugar consumption correlates with increased inflammation, too, and chronic inflammation is known to promote cancerous initiation, growth, and metastasis. So, keeping sugar intake low could be another way that doctors might stymie some pathways that make cancer worse for patients who are already fighting the disease.

image of cancer-causing fructose

Obesity, Sugar, and Cancer Risk

Given that the causes of many cancers are linked to being overweight or obese, Dr Lustig’s treatment plan would also focus on dietary obesity management. Not accidentally, sugary foods are usually loaded with calories and low in satiety, which makes them a reliable source of energy but contributes to weight gain. A proper balanced diet, together with daily physical exercise, would be part of his strategy of medical care for cancer.

Practical Dietary Changes

Specific recommendations for cancer patients include concrete goals – removing sugary drinks, avoiding products with ‘added sugar’ such as packaged foods, fruit juices, snacks, baked goods, sports, and energy drinks, and seeking whole (i.e., unprocessed) foods. These all contain fiber and essential nutrients that are deficient in processed foods, the consumption of which has been linked to the factors that encourage cancer growth (i.e., metabolic markers).

The Bigger Picture in Cancer Care

But if Lustig had been correct, he would have mentioned that the risk of cancer and treatment options are not only related to sugar. Lifestyle choices, environmental factors, and genetics all play important and necessary roles in comprehensive care. In straightforward terms, the dietary management of cancer would go together with conventional oncological management (chemotherapy, radiation, or surgery, depending on the cancer type and stage) for the best care.

image of text message to individuals to check their blood glucose levels


The views and research on how metabolism and sugar affect health shape his approach to treating cancer patients. In cancer treatment, dietary and metabolic factors can be just as important as chemotherapy in reducing cancer’s ability to spread, prolonging patient survival, and enhancing the efficacy of chemotherapy. Changes in our sugar consumption can thus have a preventive role in not just reducing our risk of developing most cancers but also potentially changing their course in patients who are already diagnosed.

We will collaborate with your doctor to develop a comprehensive plan that integrates naturopathic treatments into your regime, improving your chance of remission and survival. Click the link for our free health assessment and consultation to begin your travel to improved health.