What do Hawaiian Punch, ketchup, and sweet and sour dipping sauce have in common? They all enhance tumor growth because they contain high fructose corn syrup (HFCS).

We've been telling people to avoid HFCS for years because it messes with blood sugar regulation, contributes to weight gain, and increases levels of bad cholesterol and triglycerides as it raises your risk for fatty liver disease and diabetes.

But if all that isn't enough to convince you of its dangers, a new study in the journal Nature shows that HFCS increases the volume of circulating nutrients that cancer cells feast on to grow.

This is concerning because Americans consume 15 times more fructose than they did 100 years ago, and that means they are overfeeding tumor cells as they overfeed themselves.

That may be why researchers have observed that certain cancers have become increasingly more prevalent — especially in people younger than 50.

Here’s the smart move if you have cancer: Avoid fructose — both HFCS and plain fructose — in prepared and processed foods.

And for everyone else, don't make your body a happy hunting ground for cells that are mutating into cancer.

Ditch all added sugars and syrups. For a sweet treat, enjoy 1 ounce of 70% dark chocolate daily.

And for more information on how to make smart food choices that keep you healthier and younger longer, check out Dr. Mike's books "What to Eat When" and "The What to Eat When Cookbook."