DOES the world really need yet another book about how to lose weight? It does, if that book happens to be written by a former commissioner of the US Food and Drug Administration.
As FDA commissioner under the first George Bush and Bill Clinton, David Kessler crusaded against the tobacco companies and their conspiracy to keep smokers hooked. Now back in academe at the University of California, San Francisco, Kessler is battling another major public health problem: the rising tide of obesity. The End of Overeating is both his diagnosis of the problem and a prescription for its treatment.
In a sequence of short, readable chapters, Kessler lays out the science behind the obesityepidemic. Modern foods have become too palatable, he says. Rich in fat and sugar, they overstimulate the brain's reward pathways, conditioning us to seek more and more. Manufacturers of processed foods and major restaurant chains all exploit this neurological vulnerability by layering fat and sugar into foods to create "craveability". "Where traditional cuisine is made to satisfy, North American industrial food is made to stimulate," Kessler writes.
And it gets worse. When we eat these hyperstimulating foods and experience the neural rewards they offer, the foods become even more stimulating the next time around. Eventually, the cues that accompany the foods - location, time of day, emotional state - become triggers that drive food-seeking behaviour. Thathabitual craving, Kessler says, is why he can't resist the plate of chocolate-chip cookies on the table during meetings.
Hyperstimulating foods offer neural rewards, making them even more stimulating the next time
Of course, there's nothing really surprising in any of this. Many of us already know that our palaeolithic bodies and brains are designed to crave the fats and sugars that were once scarce but are now abundant, and that over time we can learn to eat from habit rather than from hunger. Still, for readers of a scientific bent, it is refreshing to see the underlying biology laid out in detail by a writer of impeccable credentials.
The real strength of Kessler's book comes in the final chapters, where he draws on the neurobiology and psychology of habit reversal to lay out a programme for breaking the tyranny of food-related stimuli and the runaway feedback loop within the brain's reward pathways. He stresses the importance of making rules that govern what one can eat and when. Such rules, especially when they allow little scope for choice, make certain foods "unavailable" - and this, research shows, can muffle the brain's cravings.
Kessler hints that this regimen has worked for him, though he gives few details - an odd omission in a book of this sort, but perhaps further evidence that this is no ordinary diet book.