Time to Retire the Low-Carb Diet Fad

A 25-year Swedish study suggests we refocus our dieting concerns on good, old-fashioned animal fat. 


"Steak, cream pies, hot fudge -- those were thought to be unhealthy -- precisely the opposite of what we now know to be true."

--Doctors in the year 2173 in Woody Allen's Sleeper

A version of Woody Allen's fantasy has in recent years been making the talk show circuit. Marbled steaks, bacon, greasy burgers dripping with cheese, we're told, are not to blame for obesity and cardiovascular disease. Nope, it's bananas, whole wheat toast, acorn squash, peas, pasta, rice and boiled potatoes that's making us fat and sick. So feel free to double up on those pork chops and sausage patties!

Unfortunately, today's long anticipated announcement of the results of a 25-year Swedish study pours rain on the porky parade. What apparently makes this report particularly potent is that it is the first nationally and regionally conducted long-term epidemiological study of low carbohydrate diets. And the results were categorical.

The study concludes that, over time, reducing animal fat intake decreased blood cholesterol levels, and that a high fat low carbohydrate diet increased blood cholesterol levels. On average, Swedes who switched from a lower fat diet to a higher fat/lower carbohydrate diet saw their blood cholesterol creep up -- despite an increased use of cholesterol lowering medication.

Yes, many people have lost weight on a low carbohydrate diet, and an entire industry has sprouted up around that claim. But while complex carbohydrate consumption in the U.S. has declined significantly since the late 1990s, American obesity rates remain the highest on the planet.

Low carbohydrate evangelists will almost certainly attack today's announcement--and perhaps this post -- with biblical fury. They'll make their usual claim: that this is yet another conspiracy of scientists who just don't get it, scientists who don't understand nutrition, scientists who somehow made it through their PhD's and MD's without knowing the first thing about how the human body works. But let's face it -- most of us know in our hearts that eschewing a breakfast of whole grains and fruit crowned with a dab of yogurt for a greasy pile of sausage, bacon, and eggs is not the road to health.

The study's head researcher, Ingegerd Johansson, put it this way:

The association between nutrition and health is complex. It involves specific food components, interactions among those food components, and interactions with genetic factors and individual needs. While low carbohydrate/high fat diets may help short term weight loss, these results of this Swedish study demonstrate that long term weight loss is not maintained and that this diet increases blood cholesterol which has a major impact on risk of cardiovascular disease.

Studies in Japan -- where consumption of saturated fat is normally quite low -- show that even a relatively small increase in dietary saturated fat can result in more cardiovascular disease: The Japanese, who enjoy the lowest obesity rates in the world, consume far more carbohydrates than do Americans. Those who insist the Japanese are somehow genetically different might consider Poland, where a dramatic decline in death from heart disease was linked to increased consumption of fruits and vegetables and decreased consumption of animal fat.

No one suggests that eating large amounts of isolated simple carbohydrates (aka simple sugar) is good for anyone; it's not. Soda pop should not play a starring role in America's diet, and sweeteners of all kinds should be consumed in moderation -- which is to say, most of us should eat less of them. But the popular folk lore that carbohydrates found naturally in fruits, vegetables and grains are responsible for the nation's epidemic of obesity and its co-morbidities of heart disease and diabetes is about as realistic as a Woody Allen fantasy.