Robert Ettinger sent me a copy of The Anti-Aging Zone,
and asked for a review of it. Overall I was not too
impressed with this book. Rather than being a serious
look at interventions on either aging, or disease risk, it
is just a potboiler pushing Sears' high protein diet.
The book is well written, and it is clear that Sears knows
how to write good copy. Although the Zone diet will not win any
support from main-stream medicine, but it is a lot healthier
than some other high protein diets on the market. His diet
is essentially the Mediteranean diet, emphasizing olive
oil, and lots of fruits and vegetables, with an extra dollop
of protein. He recommends cutting the fat off meat, and
consuming only egg whites (which lower cholesterol), and
discarding the egg yolks (which increase cancer risk).
Unlike other high protein diets I doubt the the Zone diet
would increase the risk of cardiovascular disease, as Sears
takes some care to avoid the obvious sins in this regard.
High protein diets generally increase cancer risk, but the
inclusion of tofu, and lots of fruits and vegetables, makes me
think the risks associated with increased meat rations would
probably be largely offset. Others considerations such as
increased kidney stone risk, and weakened bones are harder
to evaluate, with the meat and fruits and vegetables offering
opposing effects. A mineral supplement would likely be a good
idea on this diet.
However the major risk associated with the Zone diet is increased risk of depression in susceptible individuals. All high protein diets suffer from this defect, and it is not particular to the Zone diet alone. This is a consequence of high protein diets inhibiting tyrosine, and tryptophan transport across the blood/brain barrier.
Like most diets, significant weight loss will not occur on the Zone diet, unless dieters are willing to go hungry. The major reason why obesity is so common, is regarded by scientists as being due primarily to a combination of the "couch potato" existence now favoured by many, and the easy availability of a wide variety of highly palatable foods. With regard to the former factor, lack of exercise is not the only fattening factor in our remote control dominated existance. Snacking during television watching, despite not being hungry is an additional factor. Weight loss has been induced in children, by restricting the hours of television watching.
The consumption of a wide variety of highly palatable foods is referred to in the medical literature as the "cafeteria diet". Feeding western style human food to rodents for example, in place of rodent chow, sets the stage for a process of rapid gorging, in which large weight gains are the net result. The incidence of obesity in Asian populations is low, despite these diets not being high fiber, high protein, or even in some cases low fat. It is an unfortunate fact of life that delicious food encourages many to over-indulge. This is the dietary factor which is primarily responsible for the obesity epidemic. If the reader is interested, as a test I suggest temporaily limiting food intake to just whole meal bread with no toppings for a one day. Record calorie intake. You may be surprised by the results. As an anti-aging or anti-disease risk book the Anti-Aging Zone falls well short of being satisfactory. Sears does not even deal with the known side-effects of high protein diets, let alone examine the effect of diet on disease risk. You will not find discussions of the effect of tomato intake on prostate cancer risk, of nuts on cardiovascular disease, of carrots on breast cancer risk, why you should cut garlic cloves open before cooking them and other such esoterica.
Living longer or in better health is not an important goal with Sears, despite the title of his book. Rather Sears goes on a confused monolog in which he discovers the answer to a question that puzzles gerontologists to this day, why humans age. He has been criticized for trafficking in falsehoods with his theories concerning eicosanoids. After reading one scathing review in the medical literature exposing Sears' quackery, I must come to the conclusion that honesty is one of Sears' strong points. (Sports Med 27(4): 213-228 Apr 1999)
The Anti-Aging Zone is not recommended.