We often hear that ‘sugar feeds cancer.’ While having elevated blood sugar levels is associated with increased risks of developing cancer, independent of other physiological factors, it is too simplistic to claim that dietary sugar consumption makes cancer grow.
Why High Blood Sugar Is Cancer Promoting:
Cancer certainly prefers to use sugar over other energy sources, but so do most cells in our body. We have to have sugar to live, so it’s not possible or desired to avoid all food and beverages that contain sugar or carbohydrates that convert into sugar in our body.
The problem comes down to the amount of sugar and other carbohydrates (mainly, unhealthful, simple carbohydrates) we consume throughout the day…most of us overdo it. Overdoing it leads to high blood sugar and insulin levels, which store the excess sugar as fat, and this fat (especially, abdominal fat) is cancer promoting by:
- secreting proteins (cytokines) that cause systemic inflammation, leading to metabolic syndrome (see below to learn more about “metabolic syndrome”)
- causing a fatty liver, leading to metabolic syndrome
- causing insulin resistance, leading to metabolic syndrome (you can test to see if you have insulin resistance with a glucose-insulin tolerance test. Read why I think this is such an important test, here.)
- secreting free radicals that can damage DNA
- secreting hormones (estrogen and other cancer growth factors) that can signal cancer cells to grow
To learn more about metabolic syndrome, I highly recommend that you listen to this excellent lecture by Dr Robert Lustig, one of the most eloquent, public health experts on this syndrome.
In short, metabolic syndrome is classified according to a number of criteria: obesity, a bad lipid profile, and insulin resistance. Metabolic syndrome can lead to numerous untoward medical conditions, including cancer. The figure, below, summarizes this.
There are many factors that contribute to obesity and metabolic syndrome (i.e. overconsumption of calories, lack of exercise, stress, lack of sleep, systemic inflammation, environmental chemicals, genetics, gut organisms, metabolic rate, testosterone levels, thyroid function, etc.), but the major culprit comes down overconsumption of simple carbohydrates.
…Oh, if it were only that simple…
Every Carbohydrate-Containing Food/Drink Has A Different Effect On Everyone:
Did you know that each person will have a different blood sugar level after consuming the same carbohydrate-containing food or drink as someone else? One individual might experience a very large spike in blood sugar levels after eating a particular food, while someone else may have a much lower blood sugar level. The person with the higher blood sugar level will also more likely have a greater propensity to gaining abdominal fat after consuming these foods or drinks.
How do we know what will happen to our blood sugar level after consuming a food or drink? I wrote about this in a previous blog article. In that article, I discussed the concepts of glycemic index and glycemic load, and referenced tables that you can use to estimate the effects on blood sugar for any food or drink. These merely represent estimates, not actual blood sugar levels that you will experience.
The only way to actually know what will happen to your blood sugar after eating or drinking any food or beverage is by testing your blood. This approach enables you to discover the effects of individual carbohydrates on your blood sugar levels.
How Do You Test?
Step 1: Buy a home blood sugar monitor and testing kit (lancets, blood sugar monitor strips, alcohol wipes)
- I found that the least painful lancing device is by Genteel, although these aren’t cheap ($129-$199.)
- You will also need compatible lancets, test strips and a glucometer.
Step 2: Find out your fasting blood sugar level. This is the measure of your blood sugar first thing in the morning, before you eat or drink anything. Record these levels for 2-3 days.
Step 3: Test your blood sugar levels just before each of your typical daily meals, and then again 1, 2 and 3 hours after each meal. Any exercise or food/drinks you consume before and after meals will affect these results, so you’ll want to keep that in mind. Keep accurate food and drink diaries so you can figure out what you ate/drank, and learn the blood sugar effects of these items. Do this for 2-3 days and record your results.
Step 4: Test you blood sugar levels after consuming various different meals, drinks and foods. Keep food diaries, and record your blood sugar levels (before, 1, 2 and 3 hours afterwards.)
Step 5: Review your results.
- A fasting blood sugar of less than 86 mg/dL is ideal
- One hour after a meal, blood sugar should be less than 140 mg/dL
- Two hours after a meal, blood sugar should be less than 120 mg/dL
- Three hours after a meal, blood sugar should return to what it was before you ate
What Should You Do If Your Blood Sugar Levels Are Too High?
(If your blood sugar levels are consistently high, discuss this with your primary care provider to make sure you don’t have pre-diabetes or diabetes.)
If your blood glucose levels are higher than these numbers, you will need to modify your carbohydrate intake.
In order to figure out how much and what type of carbohydrates you can eat, you’ll need to experiment with your blood glucose meter.
- If you eat a bowl of cereal and your blood sugar climbs to 180 mg/dL one hour later, this tells you that you will either need to avoid this cereal or cut back on the serving size. If you love this cereal, try eating a smaller portion next time and see what effects this has on your blood sugar.
- If you go out and eat Vietnamese Pho soup with noodles, and egg rolls wrapped in lettuce, dipped in fish sauce, and your blood sugar shoots up from 100 to 170 one-hour later, you will need to make some dietary changes. Next time, try reducing the portion sizes by 50% and retest. If your glucose levels are still too high, perhaps this combination of foods isn’t the best choice for you.
- Preferentially choose foods that are listed as having a “low glycemic index” or “low glycemic load.” After consuming these foods, test to see if these estimated blood sugar effects apply to you. (Read my blog article on this.)
- Add more fiber-rich plants to your meal, and test to see if this helps to reduce your blood sugar levels. Fiber both binds to dietary sugars and speeds intestinal transit, reducing sugar and fat absorption from the gut.
- You can also take a natural fiber supplement, called “Glucomannan” before meals to reduce carbohydrate and fat absorption. Glucomannan is a natural, water-soluble dietary fiber extracted from the roots of the elephant yam, also known as konjac. I like Natural Factors WellBetX (Take 2 to 4 capsules with a 8-16 ounce glass of water, 5 to 10 minutes before meals. Don’t take any medications within 1 hour before or 2 hours after taking it because the fiber may absorb the medication.)
Using this detective-like approach of testing your blood sugar response to various food and drink items is a powerful tool to help you keep off extra abdominal fat, and reduce your risk of metabolic syndrome.
Keep in mind that many other factors in addition to your carbohydrate intake may also affect your blood sugar (i.e. stress, lack of sleep, certain medications, lean muscle mass, systemic inflammation, insulin resistance, etc.) Your glucose meter can also be a useful tool to assess how these factors might be impacting your blood sugar levels.