That substance is acrylamide and it's potentially causing cancer. The initial alarm was raised back in April when the Swedish National Food authority
sent a news report saying that raised levels of acrylamide had been found in
some starch based foods cooked at high temperatures.

  According to the World Health Organization, further studies backed up those findings. 

Seems the higher the temperature, the higher the levels of acrylamide. French fries,
according to the studies so far, have had the highest levels of this substance.
Potato chips are up there too. And it doesn't matter if they're baked or fried.

"It's the first time we have dealt with a substance that is possibly harmful to
humans. It is in laboratory animals. People should eat a balanced diet, which includes
fruit and vegetables, and they should eat moderate amounts of fatty foods. At the
moment, we have no reason to say please avoid eating this or that food," Arnold Dieter
of Germany's Federal Institute of Health said.

Scientists say the big challenge is figuring out the chemical reactions and conditions
that lead to acrylamide to see if there's a way to avoid its buildup in food.

So far, though, and this must be emphasized, there is no proof that the acrylamide
in some foods causes cancer in people.

What should you do?

The experts say eating a moderate amount of a wide variety of foods remains the best
nutrition advice until they can better get a handle on this.