The CHD-cholesterol story took another fascinating turn that further twisted the knife in the conventional theory. It's been known for some time that it's not the total cholesterol that's important, but the ratio of HDL (high-density lipoprotein) to LDL (low-density lipoprotein) cholesterol. The higher the relative levels of HDL, the lower the risk of CHD.

A further discovery is that there are two types of LDL, one of which is more CHD-related than the other. The key may not be so much density as size: the smaller the LDL particle, the deadlier it is. Researchers divided LDL into phenotypes A (big and relatively harmless) and B (small and 'bad').

And once again, a high-fat diet is the winner. In a study by the prestigious Lawrence Berkeley National Laboratory in California, researchers found that a 20-per-cent-fat diet given to healthy men produced around 50 per cent LDL(B)s in the blood, but this fell to 20 per cent when the diet was 45-per-cent fat. So, there's a clear inverse relationship between dietary fat and 'bad' LDL(B)s. They also found that the lower-fat diets converted many of the men's harmless As into deadly Bs (Am J Clin Nutr, 1999; 69: 411-8).

It's evident that cholesterol is not the simple story we've been led to believe it is-nor is the idea that 'fat leads to heart disease'. The most crushing blow so far was delivered by Swedish doctors, on announcing the results of a five-year study of nearly 30,000 middle-aged people in Malmo. Looking at fat intake and deaths-particularly from cancer and heart disease-the only correlation they found was with female cancers, where a high-fat diet appeared to be harmful.

But with heart disease or deaths in general, no links were found. High fat intakes were not associated with higher death rates-in fact, quite the reverse. The highest fat intakes resulted in the fewest deaths-and vice versa. "Current dietary guidelines concerning fat intake are generally not supported by our results," they concluded-in other words, the official advice to keep total dietary fat below 30 per cent and saturated fats below 10 per cent is simply wrong (J Intern Med, 2005; 258: 153-65).

The Swedish experience is mirrored in many other countries and populations, with high-fat diets showing either beneficial health effects or, at least, no adverse ones. Clearly, a total rethink is needed regarding fats, cholesterol and health.

High Fat and Healthy
A few enlightened doctors are already speaking out in defense of fats, recognizing that the conventional anti-fat health message is topsy-turvy. "We need a lot of fat," says neurologist Dr Russell Blaylock. "Fats form many of our hormones, allow our cells to communicate, make up cell membranes, comprise 60 per cent of the brain and enhance immunity, just to name a few of their benefits."

In fact, the kind of fat the body itself makes is saturated; it's used as a vital store of energy, and some recent research has shown that the body needs an intake of saturated fats to help utilize its own fat stores (FASEB J, 1988; 2: A852).

There's also new evidence that high-fat diets can help neurodegenerative disorders such as Alzheimer's and Parkinson's-in fact, in a "broad range of disorders involved with the death of brain cells" (Behav Pharmacol, 2006; 17: 431-9). Conversely, low saturated-fat levels can cause fatigue, poor concentration and depression. The reason is thought to be a lack of cholesterol, as the serotonin receptors in the brain need cholesterol to function properly (Br J Psychiatry, 2000; 176: 398-400).