The Never-Ending Diet Wars

Using state-of-the-art measures, in a series of randomized controlled trials, we found that this low-fat diet (plus moderate exercise and stress management techniques) caused reversal of coronary heart disease after only one month, even more reversal after one year, and still more improvement after five years. We also found that it could stop or even reverse the progression of early prostate cancer. Our latest study, published in the Proceedings of the National Academy of Sciences, showed that these diet and lifestyle changes caused beneficial changes in gene expression in over 500 genes in just three months-"turning on" disease-preventing genes and "turning off" genes that promote heart disease, cancer, and other illnesses. This is why Medicare is now covering intensive lifestyle programs such as the one I recommend.

However, studies of people who go on an Atkins diet showed that their heart disease actually worsens when heart disease was actually measured rather than just risk factors.

In other words, improved health, not just weight, is important.

The current NEJM study statement that the low-carbohydrate Atkins diet has more favorable effects on HDL-cholesterol levels is based on the observation that HDL-cholesterol levels are higher on an Atkins diet than on a low-fat diet.  Remember, HDL is just a risk factor for heart disease. We measured the effects of a healthy low-fat diet on actual disease states, not just on risk factors.

As I have written about before, there is tremendous confusion about what HDL does among both health professionals, as well as in the general public. There is often a simplistic view that HDL is good, so that anything that raises HDL is good for you, and anything that lowers it is bad for you. Nothing could be farther from the truth.

Your body makes HDL to remove excessive cholesterol from your blood and tissues, a process known as "reverse cholesterol transport." Think of HDL as the garbage trucks of your body.  HDL transports cholesterol back to your liver where it is metabolized and removed from your body. Your body's ability to make more garbage trucks (i.e., raise your HDL) is, in part, genetically determined. Some people can make more garbage trucks than others.

Most Americans eat a diet that's relatively high in saturated fat and cholesterol—i.e., a lot of "garbage." Those people who have a lot of garbage trucks—in other words, who have high HDL levels—are more efficient at getting rid of extra fat and cholesterol in their diet. As a result, they have a lower risk of a heart attack or stroke than those who eat a high-fat, high-cholesterol diet who have lower HDL levels. However, the relationship of HDL to risk of heart disease and stroke assumes that people are not changing their diet.

Not everything that raises HDL is good for you. For example, if you increase the amount of fat and cholesterol in your diet (e.g., an Atkins diet), you may increase your HDL because your body is trying to get rid of the extra "garbage" (fat and cholesterol) by increasing the number of available garbage trucks (HDL) if you are genetically able to do so. Eating a stick of butter will raise HDL in those who are able to do so, but that does not mean that butter is good for your heart. It isn't.

Not everything that lowers HDL is bad for you.  If you change from a high-fat, high-cholesterol diet to a healthy low-fat, low-cholesterol diet, your HDL levels may stay the same or even decrease because there is less need for it. When you have less garbage, you need fewer garbage trucks to remove it, so your body may make less HDL. Thus, a reduction in HDL on a low-fat diet is not harmful.