Most people don't realize that the average American has four orders of fries a week, so this issue is important for many. McDonald's fries now come from huge manufacturing plants that can peel, slice, cook, and freeze 2 million pounds of potatoes a day.

The major issue with French fries may not be trans fat, although some fast food chains' fries contain over 30 percent trans fat.

What most people fail to understand is that once you heat oil to a high temperature in the presence of oxygen and light you can produce all kinds of different damaged toxic oil molecules that are cyclized, cross-linked, fragmented, bond-shifted, and polymerized.

If food turns brown during the cooking process, it has dried out, been overheated, and become toxic. The toxic molecules change the expression of many genes in the direction of inflammation and cancer. When you exceed a safe temperature and turn food brown you not only change the chemistry of the food, you also damage the oil.

The nature of chemical reactions is that for every 10-degree Celsius rise in temperature, the rate of chemical reactions (with oxygen, light, metals) at least doubles, and may even triple or quadruple.

In addition to the damaged fats, other toxic substances, like acrylamide, are created when you fry potatoes. Acrylamide appears to be a potent carcinogen and was only recently discovered a few years ago.

I have long held the position that eating a French fry is probably worse than smoking one cigarette, and there is some research to support this assertion. That is one of the reasons why I place them at the front of the pack of the five worst foods you could possibly eat. 

Cooking with any oil can be problematic, but if you are going to do it, without any question in my mind coconut oil is probably the best one to cook with. This is because it has the least amount of unsaturated bonds, which are highly susceptible to heat damage. It also has the highest melting point and is a solid until about 76 degrees Fahrenheit.