Cancer Survivors Ask: Does Sugar Feed Cancer?



Cancer Survivors ask me very frequently, "Does sugar feed cancer?"

It's a loaded question because the answer is yes and no.

My main concern in discussing this topic is I don't want you feeling so worried about eating sugar that you don't give yourself the nourishment you require after cancer.  Eating too few carbohydrates will exacerbate symptoms of cancer related fatigue and that is definitely something we don't want around here.

So let's clarify a few things about sugar and cancer.


All cells need sugar to function.  Cancer cells use a lot of energy and so require a lot of nutrients, including sugar, to thrive.  This is why cancer patients lose weight - the cancer is essentially robbing all your energy.  There are some preliminary studies looking at whether starving cancer of sugar will decrease the tumor's ability to grow.  Some of these studies have shown that starving the tumor does retard its growth, but these studies are VERY preliminary and cannot be applied in standard treatment.

Too much sugar in your diet can lead to a generalized state of inflammation in the body.  The inflammatory environment can make cells clumsy, essentially less efficient at carrying out the many important tasks they need to do - like telling themselves when and where to divide.  This of course is a "cancer friendly" environment and can encourage tumors to grow.  So in terms of inflammation, decreasing sugar intake is advisable.

Diets high in sugar also cause weight gain.  Obesity is a risk factor for many cancers.  Researchers believe that the increase in certain types of cancers is directly linked to the increase in obesity in our society.  For me, this is the most important reason to decrease sugar in your diet.

So how much sugar should you eat?  According to UC San Francisco, adult women should limit their sugar intake to 6 teaspoons a day, or 25 grams.  Adult men should limit their sugar intake to 9 teaspoons or 38 g. 

A 12 ounce can of soda has 11 teaspoons (46.2 grams) of added sugar.  So, if a woman drinks a cola, she's already almost doubled her recommended daily allowance of sugar!  You can see that we must be extremely conscious of sugar intake to eat safe amounts and decrease cancer risk.

The Guide

Here is some simple advice for decreasing added sugar intake:

1. No soda, juice, sports drinks, prepared smoothies, or coffee drinks.  Don't drink your sugar!

2. No sweet breakfast foods like pastries, donuts, muffins, cereals, breakfast bars, or sweetened yogurts.  Especially watch for breakfast foods in packages that are highly processed.

3. No candy or desserts on a regular basis - we're talking once monthly at best.  If you are having a treat, choose dark chocolate that is equal or greater than 70% cacao.

4. Bottled salad dressing, bbq sauce, marinades, and pasta sauces can be extremely high in sugar.  Make your own, and use reasonable serving sizes.

5. Fill your plate- breakfast, lunch, and dinner - with homemade dishes containing vegetables, healthy fats, and proteins.  You will eat less sugar by default and feel satisfied!  Research shows that most people don't over eat naturally occurring sources of sugar like fruit and vegetables.  They tend to contain fiber and other nutrients that fill you up and trigger your normal hormonal response to stop eating.  

6. Eat whole grain foods like whole grain breads and pastas. These complex carbohydrates are a healthy substitute to refined carbohydrates because they have more vitamins, minerals, and fiber. Whole grain substitutes like barley and quinoa are also good alternatives to refined carbohydrates.


Sugar intake is a hot and complicated topic in Oncology.  If you'd like more, reliable information, I would recommend checking out UC San Francisco's Sugar Science website.  It's a fantastic resource from a highly esteemed institution.

I also suggest you download Brio's FREE Low Sugar Meal Plan.  Click below to get this 7 day meal plan complete with nutrition information, shopping lists, and delicious recipes to start you off in a healthy, low sugar direction!

Decreasing sugar intake is so important for you.  It will reduce fatigue by stopping the blood sugar swings that contribute to mood and energy imbalances.  It will also decrease your future cancer risk and improve your overall health.  

A win-win in my book.