You have probably heard that sugar feeds cancer. When I was diagnosed with breast cancer, I asked my conventional oncologist about this, and he said it wasn’t true. He thought I should just eat a healthy diet. The conventional point of view seemed to be that the best diet for preventing and surviving cancer consists of filling approximately 50% of one’s plate with high fiber fruits and vegetables (mainly vegetables), 25% protein, and 25% whole grain carbohydrates, with healthy fats in moderation. They believe that any link between sugar and cancer is indirect: too much sugar can cause obesity, and obesity can affect hormones, and certain hormones might increase the risk of some cancers, including breast cancer.

However, my integrative oncologist disagreed: He thought that to prevent or survive breast cancer, people should make considerable dietary changes, including avoiding sugar and refined carbohydrates. Of course, I would have preferred to believe that these changes were unnecessary, but when I Googled “research showing links between sugar and breast cancer,” there was some research evidence. For example, researchers at the University of Texas MD Anderson Cancer Center published a study in the journal Cancer Research using mice fed sucrose-enriched diets for 6 months. The mice had significantly increased growth in both primary breast tumors and lung metastasis. The researchers also measured inflammation, and they concluded that sugar’s effect on the inflammatory pathway fuels cancer growth: Inflammation causes cancer and sugar causes inflammation. They noted that finding risk factors for breast cancer is a “public health priority,” and their study provides evidence that dietary sugar intake has a role in breast cancer development.

Conventional oncologists, if they are aware of this research, might argue that there are no comparable human studies. My point of view is that if I wait until conclusive human studies are eventually done, I could be dead. I am at high risk of recurrence or metastasis, so I have to be cautious. I felt that I needed to change my diet. However, the exact changes that needed to be made were not completely clear.

Which sweeteners are healthy and unhealthy is not an exact science. Opinions change. The only opinions that seem to be unchanging are that white and brown sugar are both bad, and that artificial sweeteners are worse. Everybody seems to agree that stevia is safe, but I don’t like stevia’s bitter aftertaste. There is a stevia blend called Truvia that tastes somewhat better, and that is apparently safe to use. When I had breast cancer in 2011, it was thought that organic agave syrup and coconut sugar were OK, but the latest opinion seems to be that agave syrup is not good because it contains fructose.

Conventional oncology doesn’t have an opinion about sweeteners so far as I know, but there are some opinions in the alternative literature. The latest word, as I understand it, is that the healthiest sweeteners include stevia; xylitol, a sugar alcohol from North American hardwood; and erythritol, a sugar alcohol from fruits and vegetables. Not as healthy, but acceptable in small quantities, are raw honey, maple syrup, white and brown sugar, and agave syrup. The worst sweeteners, which should be completely avoided, are fructose, fruit juice concentrate (which contains fructose), high-fructose corn syrup, and artificial sweeteners such as aspartame, sucralose (Splenda), and acesulfame potassium (Ace-K), found in diet Coke and other products. (It should be noted that the amount of fructose in whole fruit is low enough so that you don’t have to avoid fruit.)  No doubt opinions will change again, so we will have to keep checking.

Other types of carbohydrates are converted to sugar in the body and must also be monitored. Sodas and sports drinks contain high-fructose corn syrup and should be avoided completely. Alcohol is controversial. My integrative oncologist says that I can have dark beer and red wine because the nutritional benefits outweigh the suspected dangers. However, it must be noted that not everyone agrees with this. Some think that vodka, gin, tequila and whiskey are better than wine and beer because they contain less sugar, and some think that all alcohol should be avoided.

Starchy foods are also converted to sugar to some extent, but some starches are healthier than others. Again, opinions change, but the best ones seem to be winter squashes, sweet potatoes, and carrots. You can also check the glycemic index and try to eat as low on it as you can.

The science concerning the best diet to prevent cancer and cancer recurrence is a work in progress, but I think that conventional oncology underestimates the importance of diet. As patients, it behooves us to be proactive and do our best to protect ourselves.