I like Dr. Katz because he's science-based. He reads a great deal of research on nutrition, he published a nutrition textbook.
He is also not a dogmatist. His basic nutrition recommendation can be summed up by Michael Pollan's dictum "Eat food. Not too much. Mostly plants". He does favor plant food, and there's an extensive base of research supporting that plant foods tend to be better for you. About saturated fat, he says that stearic acid has pretty much been exonerated, lauric acid may be OK, but palmitic and myristic acids are definitely harmful.
You can look up the amount of individual fatty acids in particular foods, in the USDA nutrients database.
Dr. Katz has sometimes been trashed by skeptics for doing research on alternative medicine. He practices "integrative medicine", i.e. he will use some alternative techniques for which there is some scientific support. He says that in cases where the mainstream medicine doesn't work, it makes sense to try the less-proved medicine.
I agree. But, I've had a LOT of medical problems in little-understood areas of medicine, like my delayed food allergies. What I've done that has been helpful, is to look into the research to see what may be helpful but hasn't yet become established clinical practice. It's more work looking for insights in research articles, but it's a lot more likely to help than going off and trying herbal medicine or acupuncture or yoga.
There IS a need for doctors to do better with patients for whom the standard medicine doesn't work. But in that case, they would do better generally to learn what the researchers think is promising, and try that.
Dr. Katz even did a study on homeopathy for ADHD (homeopathy didn't help). "Homeopathy" can mean a lot of different things, both herbal medicines that could plausibly help AND remedies that are so diluted there's no "active ingredient" left. If the "homeopathic" remedies were the kind with no active ingredient, you already know what the outcome will be.
I bumped into Dr. Katz because I got my hair cut recently.
The woman who cut my hair was raving about her new gluten-free diet, how she felt so much better, etc. etc.
I told her a couple years ago that she should get tested for celiac disease, which is treated with a gluten-free diet, because she said she had Graves disease, which is an autoimmune thyroid disease. If you have autoimmune thyroid disease, it's more likely you have celiac disease.
She didn't get tested or go gluten-free. But this time, she told me about 5 symptoms of celiac disease that she had had, and all the problems that went away on a gluten-free diet! So she likely does have celiac disease.
What inspired her to go gluten-free was the book Grain Brain. There have been a couple of popular books recently, Grain Brain and Wheat Belly, related to gluten-free diets. A lot of popular health books are mostly bogosity, which is what these are. There's a LOT of undiagnosed celiac disease and non-celiac gluten sensitivity, AND little-understood food hypersensitivities that aren't classical food allergies. The authors are making tons of money by exploiting this, and linking gluten to other preoccupations of the public. They are doctors and this is one way to make money out of one's MD degree.
Wheat Belly links gluten to being overweight. I don't know of any research evidence for this. People with celiac disease often actually gain weight on a gluten-free diet, because they're better able to absorb their food. People in general might lose weight on a gluten-free diet, simply because it makes them pay attention to their eating and rules out some common indulgences.
Grain Brain claims that gluten (and carbs in general) is toxic for the brain. Gluten has been associated with many psychiatric and neurological problems - schizophrenia (for a subset of schizophrenics), autism (very tentatively), epilepsy, ataxia, peripheral neuropathy, etc. etc. BUT, that's for a small minority of people. There's no evidence that gluten (or carbs) are bad for the brains of people in general.
So I dug up an Atlantic magazine article where a skeptical journalist investigated some of the research that supposedly supports the claims in Grain Brain, and found the research references did not support the claims.
I emailed this link to the woman who cuts my hair, along with a caution that while it's great she's now gluten-free, but the rest of the claims (all grains are bad, all carbs are bad) are not supported by science.
The Atlantic magazine article mentioned Dr. Katz and his book Disease Proof. Curious, I looked it up on Amazon. The reviews of it have a lot of the kind of reviews so common for nutrition books on Amazon: people panning the book because the author doesn't agree with their pet idea.
For example, Dr. Katz says in this book that skim milk is better than whole milk. This is because whole milk has a lot of the dangerous saturated fats, palmitic and myristic. And he says because of those calories you aren't getting in skim milk, you can eat more of better food (more fruit and vegetables, say).
But a lot of people trashed his book because he recommended skim milk. They are believers in the gospel that "saturated fat is fine".
I got into a discussion with some of the reviewers who panned the book because it recommended skim milk - and it sounds like they have delayed food allergies, because they talked about feeling jittery after eating certain foods. This jitteriness - which used to be called "reactive hypoglycemia" - is a symptom of hidden delayed food allergies.
There was a study, "Suspected postprandial hypoglycemia is associated with beta-adrenergic hypersensitivity and emotional distress", that investigated people who described these adrenaline-like reactions to simple carbs or sugar.
"Beta-adrenergic hypersensitivity" means that the beta-2 adrenergic receptors in the GI tract are more sensitive to adrenaline than usual, or more of these receptors have been made.
Another function of these receptors is to inhibit the release of histamine from mast cells!
So it makes sense that more of these receptors would be made in the gut, when the body is trying to suppress the symptoms of delayed food allergies. Antihistamines also help to suppress these symptoms.
So if someone eats a food they have a hidden delayed food allergy to, the normal adrenaline release after eating the food makes them feel jittery, because the beta-adrenergic receptors are busy suppressing histamine release, and this results in hypersensitivity to their adrenaline.
Milk is a common food allergen. And the fat in whole milk, probably lowers the glycemic index of the food and suppresses somewhat the adrenaline release after eating it - thus suppressing the jittery feeling.
The "emotional distress" mentioned in the study was "higher anxiety, somatization, depression, and obsessive-compulsive scores than controls".
I had a lot of anxiety, depression and some compulsiveness because of delayed food allergies. The somatizing part might simply mean that people correctly interpreted some of their emotional reactions as caused by the food they ate.
A lot to take in.
Yeah, I started writing about the trail I'd followed recently, and it was a long one :)
To me, the most interesting part was the discovery about how beta-adrenergic hypersensitivity might relate to delayed food allergies, something that had puzzled me.
Others might be interested in Dr. Katz's book. I read the excerpt on books.google.com and it might have useful suggestions, like his idea of replacing "willpower" with skills. He's a specialist in preventative medicine and he has a particular concern with why so many Americans are overweight, and what can be done about it. Many of his Huff Post blogs are about that.
ps I really appreciate Dr. Katz's non-dogmatic attitude, because opinions about nutrition and health in general are so polarized. It's like people establish a Camp in their nutritional position, and then Defend it. He's taken a middle ground between the alternative-medicine types and the anti-alternative-med "guardians of science". And he gets trashed by both.
I'm dubious about his version of the middle ground, but I like a lot of what he writes.
For example, here's a post by Dr. Katz on preventing Alzheimer's.