Carbs-vs.-Fats Debate? the last words

Some specific findings
The result of this methodology was a set of findings that are about as reliable as findings get in the area of diet and weight control. Here are some of the significant bits.

After one year, the low-carb subjects had shed an average of 8 more pounds than the low-fat folk. Members of the low-carb group also lost notably more body fat, and although the study did not include any exercise or physical activity requirements, they experienced a gain in lean muscle mass. In contrast, the low-fat dieters who lost weight lost more of it in the form of muscle than fat.

The low-carb group enjoyed these results even though saturated fats made up 13 percent of their daily calories (the American Heart Association has been recommending a limit of 6 percent), and even though fats of all kinds made up 40 percent, compared to the generally recommended limit of 30 percent.

The low-carb group also saw striking reductions in their triglycerides and inflammation indicators, and a greater increase in good HDL cholesterol than the low-fat group.

And finally, there is the Framingham Risk Score, which is too detailed to explain here but which is an algorithm that is used to estimate the risk that an individual will develop a cardiovascular disease within the next ten years. You can probably guess where we’re going with this:

The low-carb people actually lowered their FRS over the course of the year, while their low-fat counterpoints saw no similar improvement.



The verdict
So in the low-fat versus low-carb debate, here are your high points. A low-carb diet:

Yields a greater reduction in weight and in body fat
Increases rather than sheds lean muscle mass
Works even if you don’t slash your calorie intake
Leaves you with a healthier heart
I think we have a winner.

This could be the definitive study on carbs vs. fat
For openers, the who and how of the study’s methodology lends it more than the usual amount of scientific street cred. Start with the fact that it was conducted by the National Institutes of Health. Whatever your opinion of government agencies, they at least have the virtue of not being on the payroll of some vested interest. With most privately produced research, and even a lot of university-produced research, there is the possibility that it was funded in part or in whole by somebody with skin in the game. When the NIH tells you that fat is okay for you, you have the assurance that their study was not underwritten, or its conclusions influenced, by the American Pork Producers Council or National Dairy Association or Interstate Corn Syrup Commission.

In addition, while the study only involved 150 men and women, they were selected specifically to ensure a racially diverse population. You might be surprised at how many research projects don’t adequately do this. There is a tendency for research conducted by academics to draw volunteers from the university community, whose demographics may bear little resemblance to the population in general. Since whites, blacks, Asians, Hispanics, and other ethnic groupings differ in their genetic predispositions to overweight and high cholesterol and cardiovascular issues, research based mostly on Caucasians under the age of 35 with college degrees may be of little application to the rest of the population.

The study followed the individuals in the low-carb versus low-fat diet groups for a year, which should be the minimum for dietary and nutritional research, but often isn’t. One reason for this is that the longer you require people to hew to a set of restrictions on what foods, and how many calories, they can consume, the more likely it is that they will stray here and there from those restrictions. And that’s where this study got very clever. Unlike virtually every other long-term diet study, this one did not place any limits on the subjects’ calorie intake. As long as you stuck to the fat or carb limits assigned to you, you could pack away as many groceries as you wanted. That overall freedom to slake your hunger makes it much easier for the volunteer to remain faithful to the relatively narrow range of prohibited items.