Monday, June 06, 2005

Where's the Evidence?

This morning's headline in the Diabetes section of screamed for attention: Best of Low-Carb and Low-Fat Diets for Weight Control. It seems the experts on the European Congress on Obesity have come up with a new idea about losing weight - combine the ideas of low-carb diets with the ideas of low-fat diets and *poof* you'll have healthy weight-loss.

Just ignore the fact that there is no scientific evidence to support such ideas.

With no clear "one-size-fits-all" approach to weight-loss this new theory smacks of yet another attempt to create one out of thin air. For decades we have heard that a low-carb approach is unhealthy, potentially dangerous and restricting too many foods. We've been told again and again that the side-effects may be undesirable and that the approach is lacking nutrients.

Yet, in the last three years, reams of data has been published on low-carb diets. And the evidence is truly compelling - low-carb diets work. They help individuals lose more weight, more body fat and spare more lean body mass than low-fat diets. For the vast majority of those who follow a low-carb diet properly, the satiety factor is high and individual satisfaction with food choices is high. And, for the vast majority [70-90%], the major health risk factors we all recognize - blood pressure, cholesterol, triglycerides, and metabolic markers - all improve!

From the data available, we know that a low-fat diet may work for some individuals - and may even be a better option for some; we also know that a low-carb diet works for others; and we know various other approaches work too. What we don't have is any data to suggest that combining a low-carb diet with a low-fat diet is safe, effective or just wishful thinking.

But that's what happens when the experts simply cannot let go of dogma that is firmly rooted. To consider the idea of recommending a higher intake of fat than the current established limit of 25-35% of calories just isn't acceptable. It doesn't matter than the evidence to-date shows a higher level of fat intake is safe on a low-carb diet; it doesn't matter than those following a low-carb diet are satisfied with their food choices; and it doesn't matter than risk factors are greatly improved with a low-carb diet. The fat content is just too high regardless of the evidence.

And the very thing they found unacceptable about low-carb diets pre-2001 - cries about a lack of supporting evidence - is exactly what they are now doing by putting forward the idea of combining low-carb with low-fat.

Where is their evidence?

No comments:

Post a Comment