Founding director of Yale University's Prevention Research Center, Dr. David Katz has become known for his studies in weight loss and healthy eating plans. To find out his views on the newest research in those areas, we talked with Dr. Katz in an exclusive interview on April 9. He offered his insights on topics ranging from Paleo plans to the best diet to his own menu.
One of the most popular current diet trends: Low-carb Paleo plans, in which dieters avoid grains and dairy and eat large amounts of protein, produce and certain fats such as coconut oil. Is it healthy?
"A true Paleo diet and lifestyle - minus the predators and parasites - would likely be very good for human health," says Dr. Katz, author of "Disease-Proof: The Remarkable Truth About What Makes Us Well" and "The Way to Eat: A Six-Step Path to Lifelong Weight Control" (click for details).
But the problem: Mammoths aren't currently roaming the earth for our dinner, he adds. Moreover, even attempting to parallel Stone Age food by eating grass-fed game is difficult.
As to those beef-and-bacon-burgers topped with eggs and fried in butter that low-carb dieters enjoy?
There is no clear evidence that our health is better with more meat in the diet. So which is better, a diet of all or almost all plants, or a diet of plants plus game like antelope? We don't know- no such studies have been done. Clearly, though, a diet of mostly plants is better by far than the prevailing modern diet.
In the context of a true Paleo diet, it would be fine to eliminate grains and dairy and get those nutrients elsewhere.
In modern context, whole grain consumption is consistently associated with decisive health benefits in population studies. So while it is possible to exclude whole grains and eat well, it is not clear that many people do so.
In addition, Dr. Katz expressed concern about the impact on the planet when it comes to consuming animal protein.
"A mostly plant-based diet is not just associated with good human health outcomes- it is the only dietary pattern that is sustainable on this crowded planet," he concludes.
And he agrees with the advice of Michael Pollan, author of "Food Rules: An Eater's Manual" and "In Defense of Food: An Eater's Manifesto," whose mantra is simple and succinct: "Eat food, not too much, mostly plants."
As for those who argue that it's time to replace fear of fats with fear of starchy and sugary carbohydrates, Dr. Katz suggests a different approach.
"We have evidence that shifting to foods rich in monounsaturated fats and omega-3 fats is actually beneficial- so why aim so low? My advice is to abandon the focus on a category of nutrient, and focus on the pattern of foods," he explains.
As to a recent meta-analysis in the Annals of Internal Medicine about saturated fats that confused many consumers, Dr. Katz advises that people stop fussing about specific fats so much.
There is a bigger fish to fry here than just fish oil, or olive oil, or lard. Dietary guidance must be about the whole diet, and should be directed at foods rather than nutrients. If we get the foods right, the nutrients take care of themselves," he says.
And when it comes to the "best" diet for health (from preventing cancer to reducing the risk of dementia) and weight loss, Dr. Katz offers this recommendation:
Overall, the 'best' diet for all health outcomes is rich in vegetables, fruits, nuts, seeds, bean, lentils, and whole grains - with or without: fish, seafood, eggs, dairy, poultry, lean meats.
For those seeking specifics on the percentage of different food groups that should compose the ideal diet, Dr. Katz recommends:
- 20 to 25 percent of calories from fat
- 20 percent of calories from protein
- 55 percent of calories from carbohydrates
He's also an advocate of making your own meals rather than rely on restaurants or fast food drive-ins to cook up unknown ingredients for you. Dr. Katz authored the preface to a book that contains both a plant-based diet and recipes: "The Plant-Powered Diet: The Lifelong Eating Plan for Achieving Optimal Health, Beginning Today."
As to the physician's own menu? It follows his guidelines, and incorporates the latest research on the benefits of dark chocolate:
- Breakfast: Mixed berries, whole grain cereal, non-fat organic plain Greek yogurt for a late breakfast; coffee
- Snacks: Water, raw walnuts or almonds, fresh fruit
- Dinner: Large, mixed green salad; cooked vegetables; often a grain, such as bulgur wheat, quinoa, or other; either a vegetarian dish with beans or lentils; or grilled fish; glass of wine
- Dessert: dark chocolate, or my wife's homemade cookies, with whole grain flours, nuts, dark chocolate (or some alternative)