The term bliss food has been created by the former head of the US Food and Drug Administration Dr David Kessler, who has just released a book The End of Overeating: Taking Control of the Insatiable American Appetite Rodale Books $30).

He believes there is an optimum blend of fat, sugar and salt that when present in a particular food makes it hard to resist. This "food alchemy" stimulates the brain in such a way that instead of satisfying hunger it produces a craving for more. He calls this the "bliss point", a term I've heard used a few years ago by Australian food scientist and new product developer Dr Robert McBride from Sensometrics.

We all know foods that we consider are "more-ish" and hard to resist - Tim Tam chocolate biscuits, Lindt dark chocolate with orange, Snickers bars, corn chips with extra flavouring like sour cream and chives or roasted tomato salsa, hot movie popcorn, chocolate mocha frappuccino and the like. We fall under their spell - when one wedge of pizza turns into half a whole, or a handful of chips leads to an empty bag. It's hard to understand why we can't seem to stop eating even when we know better.

According to Dr Kessler, such foods formulated by food scientists can stimulate the reward or pleasure centre of the brain and trigger a "bliss point".

But does this make them addictive? It certainly backs up my view that modern junk foods are "impossible to resist", as Dr Kessler says. How much of this is due to the unique taste of the food or the fact that we live in a world where food is always available, kilojoule-dense, affordable and designed to make you want to eat more of it is anyone's guess.

But is it time to stop blaming individuals for being overweight or obese? In the end, there still remains the final element of personal responsibility. Sure, certain foods may have been formulated to be "irresistible" but they're only irresistible if you put them in your mouth. It's time to exert some will power and don't buy them in the first place and then you won't have a problem.