Food Science Cynicism

David Mendosa Living With It Medical Journalist Living with Diabetes and Author of Fitness and Photography for Fun, www.mendosa.com/fitnessblog After earning a B.A. with honors from the University of California,... Send Message Subscribe: David Mendosa

Thursday, January 24, 2008
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The "bombshell" in this review, Pollan writes, is the statement that, "It is now increasingly recognized that the low-fat campaign has been based on little scientific evidence and may have caused unintended health consequences." Only trans fat "can contribute to increased risk of CHD [coronary heart disease]."

The total levels of fat in our diet apparently has little bearing on the risk of heart disease, Pollan summarizes. But the ratio between types of fat does, specifically between the omega-3 fatty acids, of which we get too little, and omega-6, of which we get too much.

The other inescapable conclusion that the Harvard experts draw is that, contrary to all the advertising, we generally just don't lose weight on a low-fat diet. "A major purported benefit of a low-fat diet is weight loss. But long-term clinical trials have not provided convincing evidence that reducing dietary fat can lead to substantial weight loss. On the contrary, there is some evidence that a diet containing a high amount of refined carbohydrates may increase hunger and promote overeating, which can lead to weight gain and obesity."

True, Pollan prefers plants to animal protein. He likes his meat as a side dish to veggies and not vice versa and encourages us to avoid "industrial meat" in favor of meat fed a natural diet.

I do share his ethical and environmental concerns with our heavy reliance on livestock. One article that he cites, "Livestock’s long shadow: Environmental issues and options," is well worth reading.

Still, I differ with his statement that, "Unlike plants, which we can't live without, we don't need to eat meat -- with the exception of Vitamin B12, every nutrient found in meat can be obtained somewhere else." Every other nutrient? Here Pollan himself seems to fall into the nutritionism trap that he lambasts the food industry and scientists for promoting, where they act as if they know what all the nutrients are. We don't. We are still learning.

In fact, we have long had excellent evidence that we don't need to eat any plants or any carbohydrate. Arctic explorer Vilhjalmur Stefansson proved this by eating nothing but protein and fat during many years of living with Eskimos (Inuit) before any of us were born and later in a controlled hospital setting. I reprint his three excellent articles on my website, beginning here.

But low-carb vegetables do provide a raft of nutrients, most of which we understand very poorly. In fact, that is one of Pollan's best arguments against the reductionist paradigm of nutritionism, analyzing individual micronutrients in isolation from the food that we eat. I won't fall into that trap, and neither do the leading exponents of low-carb diets.

"There is no such thing an an essential carbohydrate for normal development, despite what the popular press might have you believe," writes Richard K. Bernstein in his book, Dr. Bernstein's Diabetes Solution (third edition, Little, Brown, 2007), page 169. "The main reason I don't suggest that you avoid all carbohydrate is that there are many constituents of vegetables -- such as vitamins and minerals, but also many other nonvitamin chemicals (phytochemicals) -- that are only recently becoming understood but that are nonetheless crucial to diet and cannot be obtained through conventional vitamin supplements."