Nathan Pritikin: 69.  Robert Atkins: 72.  Roy Walford: 79. Adelle Davis: 70.  Aveline Kushi: 78.  Marjorie Shostak: 51. Jack LaLanne: 96.  Ancel Keys:100.

David Murdock is a billionaire who believes that he knows the formula for the perfect diet.  Not only has he built his own research institute to refine his theories, but he is confident that his food choices will keep him alive to the age of 125. This would seem to be quite the claim since the longest documented lifespan is currently 122, it was a woman, and it occurred only once.  Nevertheless, Murdock is dismissive of those who eat differently.

According to an article by Frank Bruni in the New York Times:

In restaurants Murdock will push the butter dish toward the server and say, “Take the death off the table.” He will ask employees or friends who are putting sugar in coffee or milk in tea why they want to kill themselves and will upbraid people leaving healthful food unfinished about the vitamins they’re squandering.

While Murdock’s judgmental bent has doubtless reduced his list of lunch companions, his  dietary certainty is by no means rare.  There are any number of books, blogs, eating experts and devoted disciples out there who purport to know the “truth.”

Here’s my message.  If you are looking for the one true diet, caveat emptor.

While we can safely say that diet is important and a strong determinant of health, there is no one diet that  has the corner on perfection.  In fact, history shows that strict adherence to specific diets does not guarantee the avoidance of medical disaster, no matter how much one believes. Since this is so obviously true, we all need to be careful about those who claim to represent the one true path.

Nathan Pritikin founded an institute based on his beliefs about a diet that was high in natural foods and very low in fat. This diet is similar to the diet that Dr. Dean Ornish advocates today. While Pritikin’s own heart disease appeared to regress on this diet, he died of leukemia at the age of 69.

Robert Atkins claimed that eating a diet that was very low in carbohydrates but included saturated fats would protect people against obesity and heart disease.  He died at 72 after a fall that was never fully explained.  Rumors persist of a cardiac history.  No autopsy was ever performed.

Dr. Roy Walford was one of the founders of the CRON movement which believes that extreme longevity can be achieved by long term caloric restriction.  The movement persists, despite the fact that Walford developed ALS (Lou Gehrig’s disease) and died at age 79.

During the 60s and 70s, healthy eating was defined by the work of Adelle Davis, a nutrition activist and author who advocated whole unprocessed foods and avoidance of  food additives.  She died of bone cancer at 70.

Aveline Kushi was the wife and partner of Michio Kushi, one of the founders of the macrobiotic diet.  This strict eating plan is often suggested to cancer patients.  It advocates high fiber, low fat, primarily vegetarian foods with an emphasis on soy.  Despite adherence to this plan, Aveline Kushi died of cervical cancer at age 78 and her husband developed colon cancer in his 80s.

Marjorie Shostak and her husband Dr. Melvin Konner were instrumental in researching and popularizing the Paleolithic diet.  Both were anthropologists who studied the diet of ancient peoples.  While Konner is still living, his wife succumbed to breast cancer at age 51.

Heloise Menell was my aunt.  She played bridge, often forgot to balance her checkbook, had her nails and hair done religiously and did no exercise.  Her diet was heavy on hamburgers and other types of meat.  She liked a good stack of onion rings when she could get one.  Her refrigerator was always filled with chocolates.  She died at 101 after a brief bout of pneumonia.

Ray Kurzweil is an author, brilliant futurist and eccentric who believes that we may by nearing the time when man will merge with machine to make humans essentially immortal.  In order to assure that he lives long enough to benefit, Kurzweil eats no sugar, few starches and small amounts of lean protein.  He also takes approximately 150 supplements orally and receives IV infusions of others.  He is currently in his 60s and claims to be in excellent health.

Ancel Keys was the man who changed America’s view of fat.  His seminal Seven Countries Study purported to show that those who ate fat got heart disease, while those who abstained did not.  The study has been widely dissected and criticized over the years, especially because of data that was conveniently excluded.  Nonetheless the study launched America on a low fat, high carbohydrate course that is believed by some to have triggered our current obesity epidemic.  Keys later became an advocate of the Mediterranean diet.  He lived to be 100 and was very physically active late into life.  When asked whether his diet had contributed to his lifespan, he wisely replied, “Very likely, but no proof.”

The basics of Jack LaLanne’s plan for longevity boiled down to complete avoidance of sugar, lots of raw vegetables and fruits, lean animal protein (not red meat), many supplements, and a great deal of exercise.  LaLanne lived to 96 and was healthy in his later years.

Jerry Berkeley was my father.  He ate a low fat diet, a ton of bread (none of it whole grain) and a large serving of fat free ice cream with chocolate syrup every night. His vegetable and fruit consumption was minimal.  He walked daily for many years after having a heart attack at the age of 50 but was later  prevented from doing so by arthritis.  He died after he fell and hit his head at 99,  At the time, he was still traveling and reading the New York Times every day.

Go figure.  The point of this exercise is not to depress you or to prevent you from working on a clean diet.  It is, rather, to relieve you of guilt.  No diet is bomb proof and no one has a corner on the truth.  Each one of us must find the diet that makes us feel best and which, in our view, gives us the best shot at health and happiness.  We can greatly reduce our risk of heart disease, diabetes, cancers and other ills with diet, but we can’t eliminate these risks.  Will we live longer if we eat better?  It’s impossible to know.

Given these truths, here are my suggested guidelines for finding the right diet for you.

1. Your diet  is good if it is helping you achieve normal blood sugar, decent cholesterol readings, low triglycerides and a good blood pressure.  If you already have some of these problems, your diet is a good one if it is lessening these markers or allowing you to decrease your medications.

2. Your diet is good if it is allowing you to stay a good weight.  That weight doesn’t have to correspond to a perfect BMI, but it should be as low as you can comfortably maintain and should stay relatively stable.

3. Your diet is good if your energy is good.  If you are sluggish or have no energy to get out and move around, look at making a dietary change.

4. Your diet is good if it exposes you to the fewest carcinogens.  We get enough exposure to cancer causing chemicals in our air, plastics, x-rays, and modern products.  Avoidance of processing and additives is the basis for every healthy diet whether it be Primarian, Pritikin, vegetarian or an Atkins variant.

5. Your diet is good if you can believe in it and stick to it.  If you are simply eating reflexively, without any specific thought, it’s unlikely that your diet is healthy.  The reason is simple: we are presented with few good choices.  In order to eat well, we have to eat mindfully.  On the other hand, exceptions like my aunt Ellie prove the rule.

6. Your diet is good if you wake up without guilt.

7.  Your diet is good if eating it makes you not only healthy, but happy.

This is the best we can do.  But even this is a lot.  In the meantime, don’t waste your time feeling badly about the fact that you don’t eat perfectly.  Find your own way.  Clean things up as much as you can and enjoy the process of personal discovery.  And by the way, (note to myself!) when you do find the diet that fits like a glove, avoid the temptation to proclaim that it is the one and only truth.

Barbara Berkeley is an internal medicine physician and bariatrician who blogs at Refuse to Regain.