T. Colin Campbell, Ph.D.

T. Colin Campbell, Ph.D.

Professor Emeritus of Nutritional Biochemistry, Cornell

For more than two decades, many commentators have discussed and cussed so-called low-fat diets and gotten away with talking nonsense. It is time to look at some facts.

Virtually all of these discussions are based on recommendations of reports of the National Academy of Sciences during the 1980s when the initial suggestion was made to reduce total dietary fat to 30 percent (from the average of 35-37 percent of calories) — I know because I co-authored the first of these reports on diet and cancer in 1982. Then, during the next decade or so, this 30 percent benchmark became the definition of a low fat diet. A myth was born because this diet did not lead to obesity, as claimed.

During the next 10 years when this low fat myth was growing, average percent dietary fat barely changed — maybe decreasing a couple percentage points to about 33 percent, at best. In reality, the amount of fat consumed INCREASED because total calorie consumption also increased. Furthermore, during this same period of low fat mythology (1980s-1990s), obesity incidence increased.

Now, enter Robert Atkins and other writers who argued that obesity was increasing because of our switch to low fat diets. By going low fat — so the mythical story went — we were consuming more carbohydrate, an energy source from plant-based foods. This was a serious misrepresentation of the facts.

By falsely blaming low fat, ‘high carb’ diets for the obesity crisis, these writers were then free to promote the opposite: high fat, low ‘carb’, high cholesterol and high protein diets rich in animal-based foods, a so-called low ‘carb’ diet. During the initial discussions of this ‘low carb’ diet, no distinction was made between the refined carbohydrates (sugar and white flour as commonly present in processed foods) and the natural carbohydrates almost exclusively present in plant-based foods.

Later, some attention was given to refined carbohydrates (sugar, white flour) as a contributor to obesity, but by then the damage due to this obfuscation had been done. ‘Carbs’ were out, protein and fat were in. By initially demonizing ‘carbs’ and so-called ‘low fat’ diets and emphasizing increased protein and fat consumption, the intended path was clear: consume a diet rich in animal-based foods instead of a diet rich in plant-based foods.

Obesity continues to climb but not because of a switch to a plant-foods rich diet naturally low in fat and high in carbohydrate (TOTAL carbohydrate, that is). Rather, obesity increases as physical activity decreases and as sugary, fatty, salty processed food consumption increases.

More serious, however, is the effect that this mythology has had on suppressing information on the extraordinary health value of diets that are truly low in fat (10-12 percent). I am referring to a whole foods, plant-based diet that avoids added fat and processed and animal-based foods. This diet contains about 10-12 percent fat, sometimes pejoratively referred to as “extremely low fat”. Call it what you will, but this diet (also low in total protein, about 8-10 percent) produces, by comparison, “extremely low” incidences of sickness and disease. In fact, it now has been shown not just to prevent these illnesses but to treat them. Importantly, this dietary lifestyle cannot be dismissed by the mythological argument that so-called low fat diets have been proven to be questionable.

Professional medical researchers and practitioners also repeat this same mantra as if it is real. It has been shown for example in the very large Nurses’ Health Study at Harvard over an observation period of at least 14 years that reducing dietary fat from about 50 percent to about 25 percent of total calories has no association with breast cancer rates. Based on this and related studies, the sole manipulation of fat within this range does little or nothing when the diet still contains such high proportions of animal based and processed foods. Total protein remains very high throughout this range and worse, the proportion of protein from animal-based sources, already high when fat is high, if anything, increases even more when fat is independently decreased.

It is time that we seriously consider the health benefits of a whole food, plant based diet, which is naturally low in total fat, animal-based protein, and refined carbohydrates but rich in antioxidants and complex carbohydrates. The health benefits that are now being reported for this dietary lifestyle are unmatched in scope and magnitude of effect. It is time to discard the gibberish about low fat diets being responsible for the obesity epidemic. This demonizing of low fat diets does not apply to whole food plant-based diets, even lower in fat, because this dietary lifestyle really works. Just try it, but stay with it long enough to allow your body to overcome your taste preferences for fat that arise from its addictive nature.


The Beef With Atkins


David Katz, M.D.

Director, Yale Prevention Research Center

A Harvard study just published in the Annals of Internal Medicine — showing higher mortality in men and women who consumed a meaty, Atkins-like diet– has likely come to your attention, given its high media profile. Predictably, the Atkins camp was quick to weigh in and tell us why the study is flawed, and just as predictably, prominent Atkins’ diet detractors, such as my friend Dean Ornish (right here on Huffington Post), were quick to highlight the study’s importance.

When the smoke from the Hibachi clears, what does the study actually mean?

As hastily noted by its detractors, the study is observational, and thus designed to show association — not prove cause and effect. Men and women — over 120,000 of them — who, over time, ate more of their calories from animal sources and fewer of them from plants were more likely to get sick and die prematurely.

How might this be something other than cause and effect? Naturally, the study controls for alternative, likely explanations for the health outcomes observed, such as smoking (if people who eat more meat also smoke, the smoking could be the true health hazard, but that’s not the answer here). Perhaps people with a genetic predisposition to get sick and die are compelled by that same gene complex to eat more meat? If you like that one, you either own stock in Atkins Nutritionals, or should be in the bridge buying business.

It is true that an observational study does not prove cause and effect. But when, in over 100,000 people, A seems to cause B, and there is a plausible mechanism, and other likely explanations have been considered and eliminated — the most logical conclusion is that A likely does cause B, until or unless a better explanation is found. The fact that a plausible thing might not be true is a long way from proving it isn’t true!

The Atkins folks are quick to note that studies show an Atkins’ diet can improve some metabolic markers. But which do you care about — dying prematurely with a high HDL, or living long and prospering despite a lower one? Ultimately, it’s health outcomes that matter and no study has ever shown that eating an Atkins’ diet is associated with any kind of improved health outcome over the long term. It is plausible that an apparent improvement in metabolic markers can actually be associated with worse health. More than plausible: cancer often reduces body fat and lowers cholesterol.

Do I think eating a high-meat, low-plant diet increases risk of death and disease? Hell ya!

The other principal complaint of the Atkins’ camp is that this isn’t the Atkins’ diet. Perhaps not, but … soy what? The Atkins’ Diet has become a moving target, as the once powerful empire — then a victim of bankruptcy — endeavors to have its side of beef and eat it, too. The new Atkins’ Diet emphasizes more plant sources of protein, such as soy, but still wants to benefit from the ‘Atkins’ brand cache. That cache did not come from soy! It came from the image of a butter-slathered pork chop on the cover of the New York Times magazine, and similar invitations to carnivorous debauchery!

Yes, it’s true you can in fact eat a relatively high-protein, plant-based diet- my friend Dr. David Jenkins called it “eco-Atkins”– and probably derive good health from doing so. But calling this “eco-Atkins” is a bit like calling a soybean an “eco-cow,” potentially confusing to herbivores and carnivores alike.

Here are the take-away messages as I see them:

The appeal of the Atkins’ Diet was never eating soy beans; it was eating bacon, burgers and such. That was, and remains, a bad idea. Bad for the animals that are raised inhumanely to be turned into food; bad for the planet that is mightily abused in the mass production of feed animals; and bad for your health. Yes, our Stone Age ancestors ate meat, but they did not get it at McDonald’s! They ate lean, wild animals that have very little in common with pastrami. If you are inclined to eat meat you secure with a bow and arrow, I withhold my objections.

Yes, it’s true you can eat a low carbohydrate diet by eating a lot of high-protein plant foods. But, frankly, once you’ve switched to a lot of plant foods it no longer matters much if your diet is high in protein or not,although direct comparison does seem to favor more carbohydrate provided the sources are right.

Butter-slathered pork chops and walnuts are both high in fat, but they are very different foods with very different implications for your health. Everything from lentils to lollipops is high in carbohydrates, but not created equal. In the end, eating wholesome food and mostly plants, is what a staggering volume of evidence suggests will help you live long, and well.

Eating wholesome foods direct from nature is far better advice than cutting carbs or cutting fat ever was. Once you’re there — and let’s acknowledge that getting there from here is far from easy for most of us! — you are already in the dietary promised land and can stop looking around for directions from anyone with something to sell. And no, Atkins does not own this real estate.
Dr. David L. Katz